Properties of Engineering Materials Lab Manual-1

ENGINEERING MATERIALS
LABORATORY MANUAL
DIABLO VALLEY COLLEGE
Mohammad Panahandeh
Ken Green
2016
Dablo Valley College
TABLE OF CONTENTS
SECTION
TOPIC
I.
Table of Contents
II.
Introduction
III.
Lab Report General Guidelines
IV.
Safety
1.
Sieve Testing (Screen Analysis) Page 1
2.
Soil Compaction Test (Proctor Test) Page 11
3.
Concrete Test Page 22
4.
Hardness Testing Page 31
5.
Tensile Test Page 42
6.
Toughness (Charpy Impact Test) Page 47
7.
Metallurgy Techniques Page 54
a.
Bakalite Mounting Procedure
b.
Specimen Preparation
c.
Etching Reagents
d.
Metallurgical Microscopes
8.
Heat Treatment of Steel Page 63
9.
Precipitation Hardening – 2024 Aluminum Page 68
10.
Hardenability of Steel (Jominy End Quench) Page 73
INTRODUCTION
Laboratory Objective
-
to better understand some of the common engineering materials and their
properties
-
to learn and practice engineering data gathering techniques and equipment and
some of the standard test procedures
-
to learn and practice organization and communication of the related testing
activities and results
-
to prepare oneself as an Engineering professional
Laboratory Policies & Procedures
1.
Class is divided into groups of 3 to 4 students
2.
Lab Preparation
a. Study the lab manual and other available material; such as: text book, AASHTO Standards
and reference internet sites.
b. Prepare the blank tables/data sheets needed for the lab.
c. Ask questions to get clear understanding before starting the experiment
d. Wear proper work cloth in the lab; no jewelry or loose clothing.
3.
Each lab session begins with a brief discussion on:
a. Instructions of the lab equipment and experiment
b. Safety precautions
c. Answer any questions related to the lab session
4.
Follow directions and keep safety in mind in all times.
5.
Practice (dry run) before execution for time-sensitive operations.
6.
Complete all calculations, graphs & tables before leaving the lab whenever possible, as more data
or information may be needed for the report.
7.
Ask the instructor to verify and initial on your data sheet, when appropriate.
8.
Clean up and put away equipment & supplies when done.
9.
Turn in lab report one week after the experiment is completed.
Note: Although data gathering is intended to be a group effort; to get
full credit for the lab report you must engage in conducting the experiment.
Additionally, unless instructed differently, each student must turn in an
individual lab report, including all computations, graphs and charts by
INDIVIDUAL efforts.
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LAB REPORT GENERAL GUIDELINES
Reports should be in printed format or neatly written. A folder is preferred for submitting each report.
Number each page except the Title page.
Title Page
-
Experiment number and title
-
Student's name and names of lab partners
-
Date (/dates) of experiment
Objective Section
Describe the purpose of the experiment in your own words.
Procedure Section
Describe how data were gathered in the laboratory.
Data Section
Include all measurements, such as: time, weight, length, size, temperature, Hardness & etc, with
equipment type and calibration readings relevant to the experiment.
Results Section
A formulation of the data and information gathered. Use graphs, photographs and diagrams to
help illustrate the data/information.
Graphing guidelines:

Use computer plots or graph paper at suitable scales.

Label coordinates/Axes and their tick marks at regular, even intervals and with units.

Mark all experiment points and draw lines or curves to help discussions.

Assign a figure number and an appropriate title to each graph, photo or diagram.
Discussions Section
Discuss in depth of what occurred, why it happened, what it means and how it may be used in
practice. Answer all lab manual questions.
Conclusion Section
Summarize the experiment results and lessons learned. Focus on the experiment objectives and
not complaints, mistakes or excuses.
References
List all articles, books & citations used for the experiment.
Appendix
Show all calculations, with accuracy analysis, handouts & etc, if possible.
SAFETY
SAFETY IS NO ACCIDENT!
Basic Safety Rules

No horseplay in the lab.

Use the equipment properly - learn the equipment before using
it.

Do not attempt to fix the equipment or operate with brute
force. Ask the instructor for assistance if you are stuck.

Goggles must be worn when using:
CUT OFF MACHINES,
GRINDERS and
BELT SANDERS

Heat treating equipment and specimens can be hazardous. Work
carefully & plan ahead.

Small quantities of acids will be used in the lab, which
should be used under the fume hood.

Be aware of the First Aid/Emergency Kit location.

Be familiar with the emergency shower and eyewash facility.
In case of injury or an accident or safety hazard,
notify the instructor immediately.
Dablo Valley College
#1 SIEVE TESTING (screen analysis)
Objective
1.
Learn sieve testing method for particle analysis.
2.
Study the relevant standards and practice soil/aggregate classification.
General Information
Screen analysis involves the use of a set of standard test screens (called sieves) to sort mixed solid particles by
size. It is useful for:
1.
Controlling the reduction or concentration processes and controlling the size of products to meet
specifications.
2.
Monitoring the condition of equipment.
3.
Predicting engineering properties (from the measured size distribution of existing particles.)
Almost all testing methods for Engineering Material tests have been standardized. Some common
standards are developed, maintained and published by:








The American Society for Testing Materials (ASTM)
The American National Standards Institute (ANSI)
The American Association of State of State Highway and
Transportation Officials (AASHTO)
The Federal Aviation Administration (FAA)
The United States Department of Agriculture (USDA)
The American Concrete Institute (ACI)
International Organization for Standardization (ISO)
Military Standards
Most of these organizations adopt similar, sometimes identical, standards. Occasionally there are significant
differences in test standards. The AASHTO standard is used for this sieve testing lab.
There are two standard sieve series, the U.S.A. Sieve Series and the Tyler Standard Screen Scale Sieve Series.
Every screen has both the U.S. and the Tyler size designations; these two numbers may or may not be the
same. (Ref. P 1-5) This lab uses the metric series similar to the British with a basic size of 1 mm rather than
the current American system with a basic size of .001 inch. When every screen in the series is used the result
is a "square root of 2" series, in which the ratio of any two successive screen sizes is √2 = 1.414. A
factor-of-two series can also be easily achieved by using every other screen.
Equipment & Supply
1.
Sieves, pans (2), lid (Fig. 1.1)
2.
Soft brass brush and Nylon drafting brush
3.
Sieve Shaker (Fig. 1.2)
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4.
Balance & Straightedge
5.
Sample of aggregate to be analyzed
Procedure
1.
Study the AASHTO standard test methods on pages 1-7 to 1-9.
2.
Determine the quantity of the sample material needed based on Step 1.
3.
Obtain the material to be tested. If necessary dry the material first.
4.
Weigh the sample (in gm), record weight.
5.
Obtain the appropriate screens, a cover and a pan.
6.
Clean the sieves by manually shaking them to remove loose particles first, and then gently tap the
rim of the frame with the wooden handle of a drafting brush. A few particles left on the screen is OK.
Never poke or push the particles out of the screen by force, as the screen would be ruined if just one
opening in the screen is deformed.
7.
Stack the screens in order; put the pan on the bottom and stack the screens from finest to coarsest
in the bottom-up fashion. (Big holes on top and small holes on bottom)
Note: The shaker accepts the most 7 screens plus a pan and a cover; divide
the screens into multiple sets of 7 screens or less. (Fig. 1.2)
8.
Put the stack in a large mixing pan. Pour the sample carefully into the top screen and then put cover
on top.
Lockdown
Coarser
Screen
Finer
Screen
Fig. 1.1
Fig. 1.2
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9.
Place the stack of screens in the shaker. Adjust and tighten the "Lockdown" to hold the stack firmly.
(Fig. 1.2)
10. Turn the hand crank at a moderate speed to sift the sample. Unless otherwise directed, sieve the
sample for 5 to 10 minutes. Remove the stack from the shaker and take it to the weigh station.
Note: If the shaker shakes too slow there will be little mixing and little
sieving; if it is too fast the particles will levitate and not fall
through the screens.
11. Separate the coarsest sieve from the top of the stack first. Then use a clean spare bottom pan to
collect the material retained in the coarsest sieve by covering it over the sieve and then turning both
over together quickly. Use a soft brass or nylon brush to gently brush the underside of the sieve with
a circular motion to collect the stuck material, being careful not to exert too much pressure against
the wire cloth. All of the particles imbedded in the screen can be removed by this process. Separate
the screen from the pan and tap the side of the frame with the brush handle to collect the remaining
material from the screen. Weigh contents of the pan to the nearest 0.1 gm and record the weight.
12. Repeat Step 11 for each sieve and the bottom pan.
13. Clean and return all equipments.
14. Ask instructor to initial the data sheet.
Calculations (required content)
1.
Calculate the Percent Retained on each sieve by dividing the Weight Retained over the original
sample weight. Record result to the nearest 0.1%.
2.
The Cumulative Percent is the sum of the percents of that line and all lines above it.
3.
Find the sum of the Weight Retained, Percent Retained and Cumulative Percent. The Weight
Retained should be very close to the original weight of the sample.
4.
Calculate the fineness modulus by dividing the sum of the Cumulative Percent column by 100.
Note: the fineness modulus of concrete aggregate is obtained in the same
manner, using the sieve series consisting of Tyler screens #100,
#48, #28, #14, #8, #4, 3/8”, 3/4”,1.5”, & 3”. The fineness modulus
is an estimate of the "average" particle size as measured by the
number of sieves from the series.
Graphs (required content)
Make a logarithmic plot of Percent Retained and Cumulative Percent Retained on the graph sheet provided (P
1-6).
Report (required content)
1.
Describe the procedure briefly.
2.
Graphs
3.
Data
4.
Present the results; refer the data and the graphs.
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5.
Discuss the results
a. Classify the material the best you can from the sieve analysis. Indicate how you arrived at
the classification for:
i.
U.S.D.A.
ii.
Highway Subgrade Materials
iii.
At least one other appropriate classification
b. What might this material be good for?
6.
Appendix
a. Directions and background information supplied
b. Various standards
c. Any other pertinent reference material
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SIEVE ANALYSIS
SCREEN SCALE RATIO 1.414
DATA AND COMPUTATION SHEET
SAMPLE _________________________________
WEIGHT OF SAMPLE _______________ gm
NAME
_________________________________
PARTY MEMBERS ______________________
DATE __________________________________
_______________________________
Sieve Openings
Sieve Mesh ID Wt. of pan Tare of Weight
& aggregate
Pan
Retained
retained
Tyler
U.S.
(gm)
(gm)
(gm)
1-1/4"
in
mm
1.250
31.5
0.875
22.4
7/8"
0.625
16.0
5/8"
0.438
11.2
7/16"
0.312
8.0
2-1/2
5/16"
0.223
5.6
3-1/2
3-1/2"
0.157
4.00
5
5
0.111
* 0.0787
2.80
7
7
2.00
9
10
0.0555
* 0.0394
1.40
12
14
1.000
16
18
0.0278
* 0.0197
0.710
24
25
0.500
32
35
0.0139
* 0.0098
0.355
42
45
0.250
60
60
0.0070
* 0.0049
0.180
80
80
0.125
115
120
0.0035
* 0.0025
0.090
170
170
0.063
250
230
0.0000
0.000
Pan
Pan
*
*
*
*
Percent Cumulative
Retained Retained
(gm)
(gm)
TOTAL
* Used for screen scale ratio 2.0 series
REMARKS: ___________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
_______________________________________________________________________________
Instructor's Initial
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Tyler Standard Screen Scale
Date
Sample Description
Name
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METHOD OF SAMPLING AND TESTING
STANDARD METHOD OF TEST FOR
SIEVE ANALYSIS OF FINE AND COARSE AGGREGATES
AASHO DESIGNATION: T 27-70
SCOPE
1.1
This method of test covers a procedure for the determination of the particle
size distribution of fine and coarse aggregates, using sieves with square
openings. The method is also applicable to the use of laboratory screens
with round openings. It is not intended for use in the sieve analysis of
aggregates recovered from bituminous mixtures or for the sieve analysis
of mineral fillers.
APPARATUS
2.1
The apparatus shall consist of the following:
2.1.1
Balance - The balance or scale shall be sensitive to within 0.2
percent of the weight of the sample to be tested.
2.1.2
Sieves - The sieves with square opening shall be mounted on
substantial frames constructed in a manner that will prevent loss
of material during sieving. Suitable sieve sizes shall be selected
to furnish the information required by the specifications covering
the material to be tested. The woven wire cloth sieves shall conform
to the Standard Specifications for Sieves for Testing Purposes
(AASHO M 92).
2.1.3
Oven - the oven shall be capable of maintaining a uniform
temperature of 110±5ºC (230±9ºF).
NOTE: Perforated plate sieves with either round or square apertures shall
conform to the requirements of ASTM: E 323, Perforated Plate sieves
for Testing Purposes
SAMPLES
3.1
Samples for sieve analysis shall be obtained from the materials to be tested
by the use of sample splitter or by the method of quartering. Fine aggregate
sampled by the quartering method shall be thoroughly mixed and in a moist
condition. The sample for test shall be approximately of the weight desired
and shall be the end result of the sampling method. The selection of samples
of an exact predetermined weight shall not be attempted.
3.2
Samples of fine aggregate for sieve analysis shall weigh, after drying,
approximately the amount indicated in the following table:
Material with at least 95 per cent finer than a 2.36 mm
(No. 8 sieve)
Material with at least 90 per cent finer than a 4.75 mm
(No. 4) sieve and more than 5 percent coarser than a 2.36
mm (No. 8 sieve)
100 g
500g
In no case shall the fraction retained on any sieve at the completion of
the sieving operation weigh more than 4 g. per sq. in. of sieving surface.
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NOTE: This amounts to 200 g. for the usual 8-in. diameter sieve. The amount
of material retained on the critical sieve may be regulated by:
(1) the introduction of a sieve having larger openings than in the
critical sieve or (2) by the proper selection of the size of the
sample.
3.3
Samples of coarse aggregate for sieve analysis shall weigh, after drying,
no less than an amount indicated in the following table:
Nominal Max. Size of
Particle
mm
In.
9.5
3/8
12.5
1/2
19.0
3/4
25.0
1
37.5
1 1/2
50
2
63
2 1/2
75
3
90
3 1/2
Minimum Weight
of Sample (kg1)
1
2
5
10
15
20
25
30
35
1
For samples weighing 5 kg or more it is recommended that sieves mounted
in frames 16 in. (410 mm) in diameter or larger be used.
3.4
In the case of samples containing substantial portions of material retained
on and passing the 4.75mm (No. 4) sieve, the composite sample weight shall
be determined in accordance with paragraph 3.3. The material shall be
separated into two sizes by the 4.75 mm sieve and the portion passing the
4.75 mm sieve shall be prepared in accordance with paragraph 3.1 and 3.2.
3.5
In the case of fine aggregate, the material finer than the 0.075mm (No.
200) sieve shall be determined in accordance with the Standard Method of
Test for Amount of Material Finer than 0.075mm. Sieve in Aggregates (AASHO
T 11) and the sieve analysis made on the material coarser than the 0.075
mm (No. 200) sieve.
PREPARATION OF SAMPLE
4.1. Samples shall first be subjected to AASHO T 11, for Amount of Material
Finer than No. 200 Sieve in Aggregate. This procedure may be omitted
provided the total amount of material finer than the 0.075 mm (No. 200)
sieve is not required and provided the accuracy requirements for the sieve
analysis do not require washing of the particles. All samples of fine and
coarse aggregate, where the percent of absorbed moisture changes for
different particle sizes shall be dried to substantially constant weight
at 110 ± 5ºC (230 ± 9ºF). Samples of coarse aggregate, where the percent
of absorbed moisture is essentially constant for the different particle
sizes, may be sieved surface dry.
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PROCEDURE
5.1
Separate the sample into a series of sizes using such sieves are necessary
to determine compliance with the specifications for the material under test.
The sieving operation shall be conducted by means of a lateral and vertical
motion of the sieve, accompanied by jarring action so as to keep the sample
moving continuously over the surface of the sieve. Fragments in the sample
shall never be turned or manipulated through the sieve by hand. Sieving
shall be continued until not more than 1 per cent by weight of the residue
passes any sieve during 1 min. On that portion of the sample retained on
the 4.75 mm (No. 4) sieve, the above described procedure for determining
thoroughness of sieving shall be carried out with a single layer of material.
When mechanical sieving it used the thoroughness of sieving shall be tested
by using the hand method of sieving as described above.
5.2
The weight of each size shall be determined on a scale or balance conforming
to the requirements specified in 2.1. If the total amount of material finer
than the 0.075 mm (No. 200) sieve is desired it shall be determined by adding
the weight of material passing the 0.075 mm sieve by dry sieving to that
lost by washing as determined with the use of AASHO T 11.
REPORT
6.1
The results of the sieve analysis shall be reported as follows: (a) total
percentages passing each sieve, or (b) total percentages retained on each
sieve, or (c) percentages retained between consecutive sieves, depending
upon the form of the specifications for the use of the material under test.
Percentages shall be reported to the nearest whole number. Percentages shall
be calculated on the basis of the total weight of the sample including any
material finer than the 0.075 mm sieve.
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#2 COMPACTION TEST
Objective
1.
Learn the significance of soil compact and how to determine the maximum density of a soil.
2.
Study and practice the relevant standards and methods.
Introduction
Compacting soil to a denser state is important for constructions because: (a) it reduces future settlement,
(b) it increases shear strength, and (c) it reduces the permeability. Although the fundamentals of
compaction are not completely understood, it is known that water plays an important part, especially in
finer-grained soils. Soil particles absorb a film of water when the water is added to a dry soil. Upon the
addition of more water these films get thicker and permit soil particles to slide over each other more easily;
this is called the lubrication process. Since the thickness of the water film on a coarse particle is negligible in
comparison with the particle diameter, lubrication effects are limited to finer-grained soils.
Because of lubrication, the addition of a small amount of water to dry soil aids the compaction process. Up to
a certain point, additional water replaces air in the soil voids; but, after a relatively high degree of saturation
is reached, the water occupies space which could be filled by soil particles and the amount of entrapped air
remains essentially constant. Therefore, there is an optimum amount of mixing water for a given soil and
compaction process to produce a maximum weight of soil per volume (i.e., density).
The purpose of laboratory compaction test is to determine the optimum amount of mixing water in soil
compacting so that the information can be used in the field to achieve maximum soil density. As the
maximum density and the corresponding optimum water content are affected by the compacting energy
used in the procedure, compacting energy must be controlled both in the laboratory and the field.
In the early days, because the construction equipments were small and could only produce relatively low
compacting energy, the laboratory method was based on low compacting energy. As the construction
equipment and procedures have been updated to produce higher energy in the field, high compacting energy
laboratory test became necessary.
In 1933, Proctor published a series of four articles on soil compaction. In the second of that series, a
laboratory compaction test which is now called the "standard Proctor" compaction test was described. Later,
a modified Proctor type test using over 4-1/2 times the energy of the standard was developed.
With the knowledge of the moisture-density relationship determined by a laboratory test, better control of
field compaction of the fill is possible. The engineer can also conduct control tests, which are field
determinations of water content and density, to insure proper compaction. The usual specification for field
compaction is for the attainment of a certain percentage of the optimum density by a certain test; for
example, a common one calls for "95% of the Modified AASHTO optimum density."
Equipment & Supply
1.
Compaction Device
a. A 4.0 inch diameter mold of capacity 1/30 cu. ft. with a height of 4.584" (Fig. 2.1,)
b. A 5.5 lb metal rammer with a 2 inch diameter circular face and a 12 in drop. (Fig. 2.2)
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2.
Sample Extruder (Hydraulic press)
3.
Scale:
4.
Balance: 1500 g capacity, 0.1 gm sensitivity
5.
Drying oven, set at 110 ± 5oC
6.
Straight edge
7.
No. 4 sieve (4.75 mm)
8.
Large mixing pan or mortar box
9.
Mixing tools and spoon, trowel, spatula, etc.
25 lb. capacity, 0.01 lb. sensitivity
10. Metal cans for water content determination
Recommended Procedure
1.
Record the weight of the empty mold with the base plate but without the collar.
2.
Obtain a representative specimen (minimum 10 lb.) of the soil to be tested. Break up all lumps in the
mortar box with a trowel or a spoon so it passes through the No. 4 sieve.
3.
Attach the collar to the mold.
4.
Put the soil into the mold to a depth of about 3 inches.
5.
Gently press the soil to a smooth top and then compact it with 25 evenly distributed blows of the
hammer, using the full drop.
Fig. 2.1
Fig. 2.2
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6.
Repeat Step 4 and 5 with a second and a third layer of about the same amount. After the third layer
compaction the top of the soil should be above the rim of the mold. If not, add another layer.
7.
Gently rotating the collar to break it loose from the soil first and then lifting it from the mold; try not
to remove any compacted soil when taking off the collar.
8.
Trim off excess soil to be even with the top of the mold. The trimming should be done with small
scraping operations using a straight edge beginning at the center and working toward the edge of
the mold.
9.
Clean the outside of the mold (including bottom) in the mixing pan to remove all loose soil.
10. Record the weight of the cylinder, the base, and soil sample.
11. Remove the base plate. Extrude the soil from the mold.
12. Obtain a representative sample of a minimum of 100 gm for water content determination. The water
content sample should be made with chunks extracted from the top, middle and the bottom of the
compacted soil. Weigh and record tare of empty can and the weight of can and wet soil.
13. Break up by hand and shovel the soil removed from the mold, remix with the remainder of the
original sample, and raise the water content by about 2 percent. (For 5Kg (11 lb.) 2 percent is 100 gm
or 100 cc of water). Try to distribute the water uniformly throughout the soil, and mix thoroughly.
Spread the dampened soil evenly in the large mixing pan, and tap the entire surface lightly with the
shovel.
14. Mix thoroughly a second time and repeat the compaction process.
15. Repeat the compaction process until there is a drop in weight of the remaining soil.
16. Clean equipment (wash off dirt and dry) and put them away.
17. Clean up the work area.
18. Ask the instructor to initial data sheet before leaving.
19. Dry the water content samples from step 12 for a minimum of 12 hours in an oven at 110 ± 5oC.
20. Record the weight of can and dry soil.
Calculations
ω = water content of wet compacted soil, based on oven dry weight of the soil, decimal
𝜔=
(𝐴 − 𝐵 )
(𝐵 − 𝐶 )
W = Total weight of wet compacted soil in the mold = Z - T
V = Volume of mold = 1/30 cubic feet in our case
The wet density, ω (weight of soil grains per unit volume of soil) can be computed from the following and
using V = 1/30 cu.-ft. to simplify:
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ω = W / V = 30 W
and the dry density, d (weight of soil grains per unit of volume of soil mass) can be computed from
δd =
δω
30 𝑊
=
(𝜔+1)
(𝜔+1)
where W is in pounds ω and d are in pounds-per-cubic-foot.
Report (required content)
1.
Complete the calculations which are required on the data sheet. Plot the results of the tests as wet
density (PCF) vs. water content (percent), and dry density vs. water content in the same graph. Plot
also the curve for dry density at 100 percent saturation, if the specific gravity of the soil is known or
can be assumed or established.
2.
Determine the optimum moisture content at the maximum density, from the plot, and the dry unit
weight in PCF at the optimum moisture content.
Reference:
1.
AASHTO T-99 MOISTURE DENSITY RELATIONS OF SOILS USING a 5.5 lb Rammer and a 12-inch drop.
a. SOILS IN CONSTRUCTION, W. L. Schroeder
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MOISTURE-DENSITY RELATIONS OF SOIL
(PROCTOR TEST)
Test No.
Weight of Mold & Wet Soil
Z
Tare of Mold
T
Weight of W et Soil
W=Z-T
W
Volume of Mold
V
Wet Density pcf
δω
Water Content (see below)
ω
Dry Density pcf
δd
WATER CONTENT DETERMINATION
Date & time
in oven
Out of oven
Container No.
Wet Weight plus Tare
A
Dry Weight plus Tare
B
Water Loss
A-B
Tare Weight
C
Dry Weight of Soil
B-C
Water Content
(% of Dry Weight)
ω
Soil Identification ___________________________________________________
_______________________________________________________________________
_______________________________________________________________________
Tested By _____________________________________________________________
Date _________________
Instructor’s Initial ________
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Appendix A. Selected Soil Information
Table 1. Soil texture classifications are defined by the USDA
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Table 2.
AASHTO classification of soils and soil-aggregate mixtures (from AASHTO M
145-91).
CLASSIFICATION OF SOILS AND SOIL-AGGREGATE MIXTURES
General
Classific
ation
Silt-Clay Materials (More
than 35% passing 75µm) [No.
200]
A-4
A-5
A-6
A-7
Granular Materials (35% or less passing 75µm) [No. 200]
A-1
A-3*
A-2
Group
Classific
ation
AAA11A-2-4
A-2-5
A-2-6
2a
b
7
Sieve Analysis:
Percent
passing:
2mm (No.
50
10)
max
--------.
425µm
30
50
(No. 40)
max
max
51 min.
------.
.
75µm (No.
15
25
200)
max
max
10 max.
35 max.
35 max.
35 max.
.
.
Characteristics of fraction passing No. 425µm (No. 40):
Liquid
Limit
----40 max.
41 min.
40 max.
Plasticit
y Index
Usual
Types of
Significa
nt
Constitue
nt
Materials
General
Rating as
Subgrade
6 max.
N.P
.
10 max.
Stone
Fragments
Gravel
and Sand
Fin
e
San
d
Silty or Clayey Gravel and Sand
10 max.
Excellent to Good
11 min.
A-7-5
A-7-6
---
---
---
---
---
---
---
---
---
---
35
max
.
36 min.
36
min
.
36 min.
36
min
.
41
min
.
11
min
.
40 max.
10 max.
41
min
.
10
max
.
Silty Soils
40 max.
11 min.
41
min
.
11
min
**
Clayey Soils
Fair to Poor
* The placing of A-3 before A-2 is necessary in the “left to right elimination process” and does
not indicate the superiority of A-3 over A-2.
**The plasticity index of A-7-5 is equal to or less than the liquid limit minus 30. The plasticity
index of the A-7-6 subgroup is greater than the liquid limit minus 30.
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Figure 1.
Relationship between liquid limit and plasticity index for silt-clay groups
(from AASHTO M 145-91).
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AASHTO T 90 – DETERMINING THE PLASTIC LIMIT
AND PLASTICITY INDEX OF SOILS
SCOPE
The plastic limit of a soil is the lowest water content at which the soil
remains plastic.
The plasticity index of a soil is the numerical difference between the liquid
limit and the plastic limit. It is the moisture content at which the soil
is in a plastic state.
REFERENCED DOCUMENTS
AASHTO T 87, Dry Preparation of Disturbed Soil and Soil Aggregate
Samples for Test
AASHTO T 89, Determining the Liquid Limit of Soils
AASHTO T 265, Laboratory Determination of Moisture Content of Soils
APPARATUS
Mixing dish
Spatula
Ground glass plate or unglazed paper
Plastic Limit Rolling device with unglazed paper (optional)
Moisture proof sample cans (3 oz. capacity)
Balance
Oven
Distilled water
PROCEDURE
Record information on SFN 9987 or 10086.
Material passing the No. 40 (0.425 mm) sieve prepared according to T 87 is
needed for this test.
If both the liquid and the plastic limits are required, take a test sample
of approximately 8 g from the thoroughly wet and mixed portion of the soil
prepared for T 89, the liquid limit. Take the sample at any stage the sample
is plastic enough to be shaped into a ball without sticking to the fingers.
Set aside and allow to air dry until completion of the liquid limit test. If
the sample is too dry, add more water and re-mix.
If only the plastic limit is required, take a quantity of air-dried soil
weighing about 20 g and mix with distilled or tap water in the mixing dish
until the sample becomes plastic enough to be easily shaped into a ball. Use
a portion of this ball that weighs approximately 8 g for the test sample.
Squeeze and form the 8-g test sample into an ellipsoidal-shaped mass.
Sub-sample to 1.5 to 2 g portions and roll between the palm or fingers and
the ground glass plate or piece of paper with sufficient pressure to roll the
sample into a uniform thread about 1/8" in diameter throughout its length.
Roll at a rate of 80 to 90 strokes per minute. A stroke is a complete forward
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and back motion, returning to the starting place. A plastic limit rolling device
may also be used. The rolling procedure should be completed in two minutes.
When the diameter of the thread reaches 1/8", break the thread into six or
eight pieces and squeeze the pieces together between the thumbs and fingers
of both hands into a roughly uniform ellipsoidal shape and re-roll. Continue
this procedure until the thread crumbles under the pressure required for
rolling and the soil can no longer be rolled into a thread. The crumbling may
occur when the thread has a diameter greater than 1/8". This is considered
a satisfactory end point provided that the soil has been previously rolled
into a thread 1/8" in diameter.
Do not attempt to produce failure at exactly 1/8" in diameter by allowing the
thread to reach 1/8", then reducing the rate of rolling or the hand pressure,
or both, and continuing the rolling without further deformation until the
thread falls apart. It is permissible to reduce the total amount of
deformation for feeble plastic soils by making the initial diameter of the
ellipsoidal shaped mass near the required 1/8" final diameter.
Gather the portion of the crumbled soil together and place in a container and
cover.
Repeat this procedure until the entire 8-g specimen is completely tested. Weigh
to the nearest 0.01 g and record. Determine the moisture content according
to T 265.
CALCULATIONS
Calculate the percent moisture as follows:
A = [(B – C)/C] x 100
A = Percent moisture
B = Mass of original sample
C = Mass of dry sample
Calculate moisture to the nearest 0.1%. The percent moisture is the plastic
limit.
REPORT
Report the plastic limit to the nearest whole number.
PLASTICITY INDEX CALCULATION
The plasticity index of soil is the difference between its liquid limit and
its plastic limit.
Plasticity Index = Liquid Limit - Plastic Limit
REPORT
Report the plasticity index to the nearest whole number.
NOTES
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Report the plastic limit as non plastic (NP) when the plastic limit is equal
to or greater than the liquid limit, or when the liquid limit or plastic
limit cannot be determined.
CALIBRATION
A calibration check of the equipment should be performed annually as a minimum,
or whenever damage or repair occurs.
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#3 CONCRETE TEST
Objective
1.
Learn how to work with concrete and its related testing.
2.
Determine the effect of curing time on the compression strength of concrete.
3.
Observe the variation and non-uniformity in the strength of a brittle material.
4.
Observe the effect of water-to-cement ratio by comparing results of other lab groups using different
water-to-cement ratios.
5.
Observe the difficulty in controlling the mixing, molding, and curing of concrete.
Introduction
Flexure strength is one measurement of the tensile strength of concrete. It measures the level an
unreinforced concrete beam or slab resists failure in bending. It is measured by loading 6 x 6 inch (150 x 150
mm) concrete beams with a span at least 3 times the depth. The flexure strength is expressed as Modulus of
Rupture (MR) in PSI (or MPa) and is determined by standard test methods ASTM C 78 (third-point loading, Fig
5.1) or ASTM C 293 (center-point loading, Fig. 5.2.)
Flexure MR is about 10 to 20 percent of the compression strength, depending on the type, size and volume of
the coarse aggregate used in the concrete. However, the best correlation for specific materials is obtained by
laboratory tests for given materials and mix. The MR determined by the third-point loading method is lower
than that by the center-point loading, sometimes up to 15%.
Concrete pavement design usually replies on a flexural strength based theory. Therefore a test to verify the
flexure strength is needed. Some also use MR for field control and acceptance of pavements. Very few use
flexural testing for structural concrete. Agencies not using flexure strength for field control generally use of
compressive strength test for judging the quality of the concrete.
Fig. 5.1
Fig. 5.2
Equipment & Supply
1.
Concrete mix material
a. Type II Portland Cement
b. Aggregate
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2.
Tap water.
3.
Scale, balance and ruler for measurement.
4.
Wheelbarrow, shovel, trowel and other mixing tools.
5.
Moisture sample can.
6.
Slump apparatus:
7.
Fifteen (15) 3" Dia. x 6" high cardboard/PVC cylindrical molds.
8.
Concrete beam mold assembly, Screw driver & 6" crescent wrench for assembling.
9.
Capping mold and pot of capping compound.
Cone, Base & Rod.
10. Wabash Compression Tester, 15 ton capacity.
11. Oven, 110 ± 5oC rating.
12. Concrete curing tank.
Concrete Mix Proportions
saturate surface dry (SSD) conditions.(3/4" aggregate, 1/25 cubic yard, 3" to 4" slump)
W/C #
Cement #
Aggregate #
Water #
.50
.55
.60
.65
.70
.80
.90
1.00
27.2
24.8
22.6
21.
19.4
17.
15.1
13.6
116
118
120
121.2
122.8
125.6
128.4
131.2
13.6
13.6
13.6
13.6
13.6
13.6
13.6
13.6
Normal
Strength
(PSI)
4500
3950
3500
3100
2800
2200
1800
1500
Procedure:
1.
Prepare the data sheet for data recording. (Ref PP 1-4 & 3-5)
2.
Determine the concrete mix to be used.
3.
Assemble the beam mold.
4.
Dampen sides and bottom of wheelbarrow.
5.
Measure out and put the proper amounts of cement, aggregate and water into the wheelbarrow.
Mix the dry material thoroughly.
6.
Put a representative sample of aggregate into a moisture can. Weigh the can, record the weight.
Place the can in the oven to dry so as to determine the moisture of the aggregate.
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7.
Measure out the prescribed amount of water for concrete mixing. Add approximately 2/3 of it to the
wheelbarrow. Mix thoroughly and gradually adding more water until the mix is "right". (Follow
instructor’s advice.) Measure any remaining water.
8.
Make a slump test. See accompanying procedure on Pg 5-8. (Fig. 5.3)
Fig. 5.3
9.
Fig. 5.4
Fig. 5.5
Quickly return the concrete used in the slump test and remix them.
Note: This is inconsistent with the slump test directions. However, for
cost and disposal considerations, we use the same material for
casting cylinders and the beam.
10. Spray inside of the cylinders with WD40 and cast 15 3"-diameter cylinders; rod them to remove
voids (air pockets.) (Fig. 5.4)
11. Cast a concrete beam; thoroughly rod the material to reduce void. (Fig. 5.5)
12. Thoroughly wash and return all equipment.
13. Clean up the work area.
14. After one day (to solidify) the cylinder and beam are to be kept moist by storing them in a moist
condition or covering up to prevent loss of moisture. Follow the procedure below:
a. Carefully remove the concrete cylinders from the molds; clean and return molds to the
storage.
b. Mark each cylinder by a waterproof marker.
c. Immerse cylinders in concrete curing tank.
15. Seven days after the casting:
a. Take 5 concrete cylinders from the mold. Cap both ends of each cylinder with bakelite and test
each cylinder for compressive breaking strength.
b. Clean up; dispose of broken concrete in dumpster.
c. Remove the aggregate sample from the oven after 24 hours; weigh it and calculate the true
moisture content of the aggregate.
16. Fourteen days after casting -
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Repeat Step 15 for another 5 cylinders.
17. Twenty-eight days after casting
a. Remove beam from mold
b. Use the Aminco portable concrete beam tester to test the beam.
Note: when possible use the longer broken piece for a second test.
c. Clean the mold and return it to its proper location. Dump broken concrete in dumpster.
d. Repeat Step 15 for the remaining cylinders.
Calculations
1.
Water content - The concrete mix proportions are given on the basis of saturated surface dry (SSD)
condition of the aggregate. In practice the actual moisture condition is different from SSD
conditions. For example, assume we are mixing a batch of 0.6 water-to-cement ratio concrete.
The assumed mix would consist of
Cement
Aggregate
Water
22.6 Kg
120 Kg
13.6 Kg
Further assume under SSD conditions, the aggregate contains 2.5% water, which means 120 Kg of
aggregate is 117 Kg dry aggregate and 3 Kg water. Suppose that when we use the aggregate it has
been sitting outside in the rain and contains 3.5% water, which means the water content is +1.0%
(1.0% more than SSD). In this case 120 Kg of aggregate consists of 1% extra water and 1% less dry
aggregate. Hence, to maintain the desired water-to-cement ration, if we know the aggregate
moisture level before we mix the concrete, we must modify our proportions.
1% of Amount of aggregate: 120 Kg x 0.01 = 1.2 Kg. Therefore
Material
Cement
Aggregate
Water
Total
2.
SSD (Kg)
22.6
120.
13.6
156.2
Correction (Kg)
0.0
-1.2
1.2
0.0
Corrected (Kg)
22.6
118.8
14.8
156.2
Breaking strength of cylinders
 =
𝐿𝑜𝑎𝑑
𝐴𝑟𝑒𝑎
, in pounds-per-square-inch
Load = load in pounds (converted from tons from the Wabash press)
Area = Cross sectional area of the cylinder, in square inches
3.
Average Breaking Strength of the 5 cylinders an any one curing time, AVE
𝛿𝐴𝑉𝐸 =
1 + 2 + 3 + 4 + 5
5
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Discard any defective cylinders and adjust the formula accordingly
Report (required content)
1.
Give mix proportions. Using the measured water content of the aggregate, indicate the actual
water-cement ratio. Assuming the mix makes 1/25 of a cubic yard, give specifications in terms of
amounts per cubic yard of concrete - specify water in gallons and cement in sacks (94# sack). What is
the water-cement ration in gallons per sack?
2.
Give the slump which was obtained. The slump can be altered by changing the amount of
water-cement paste, compared to the amount of aggregate. The more paste, the more slump; the
less paste, the less the slump.
3.
Make a plot of breaking strength (PSI) vs. time (days) for the cylinders. Plot a point for every cylinder
broken, and plot the calculated average values. Draw a "curve" through the average points.
4.
Specify the measured flexure strength.
5.
Discussions
a. Discuss the observed scatter in the data.
b. Discuss the effect of curing time on compression strength.
c. Discuss the effect that neglecting the variation in the water content of the aggregate
(compared to SSD) might have on the properties of the concrete.
d. Discuss the advantages/disadvantages of a low slump mix compared to a high slump mix.
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AMINCO COLLAPSIBLE STEEL MOLD
For Casting Standard 6 x 6 x 3 6 inch Concrete Test Beams
CORRECTION FACTORS FOR 6" x 6" OFF-SECTION CONCRETE BEAMS
Multiply breaking reading by factor for true Modulus of Rupture
Based on standard test span of 18 inches.
DEPTH OF BEAM
WIDTH OF BEAM
5.75"
5.80"
5.85"
5.90"
5.95"
6.00"
6.05"
6.10"
6.15"
6.20"
6.25"
5.75"
1.136
1.126
1.117
1.107
1.098
1.089
1.080
1.071
1.062
1.054
1.045
5.80"
1.117
1.107
1.098
1.088
1.079
1.070
1:061
1.053
1.044
1.036
1.027
5.85"
1.098 •
1.088
1.079
1.070
1.061
1.052
1.043
1.035
1.026
1.018
1.010
5.90"
1.079
1.070
1.061
1.052
1.043
1.034
1.026
1.017
1.009
1.001
.993
5.95" 1.061
1.052
1.043
1.034
1.025
1.017
1.008
1.000
.992
.984
.976
6.00"
1.043
1.034
1.026
1.017
1.008
1.000
.992
.984
.976
.968
.960
6.05"
1.026
1.017
1.009
1.000
.992
.984
.975
.967
.960
.952
.944
6.10"
1.010
1.001
.992
.984
.976
.967
.959
.952
.944
.936
.929
6.15"
.993
.985
.976
.968
.960
.952
.944
.936
.929
.921
.914
6.20"
.977
.969
.961
.952
.944
.937
.929
.921
.914
.906
.899
6.25"
.962
.953
.945
.937
.929
.922
.914
.906
.899
.892
.885
6.30"
.946
.938
.930
.922
.915
.907
.900
.892
.885
.878
.871
6.35"
.932
.924
.916
.908
.900
.893
.885
.878
.871
.864
.857
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FLEXURE TEST OF CONCRETE BEAM
SMAPLE REPORT FORM
(Aminco Tester)
Project ___________________________
Beam Series ___________________
Location of Job _____________________
Total No. of Beams ______________
Source of Materials: ______________________________________________________
Fine Aggregate ________ Coarse Aggregate ______ Cement _____ Water _____
Slump __________ Air Temperature _______ Mix _________________________
Date Poured __________ Tested By _________________________________________
Limits of Day’s Pour __________________________ Total Yards Poured ____________
Climate Conditions _______________________________________________________
Remarks _______________________________________________________________
Beam No.
Date
Tested
Age in
Days
Average
Width
Average
Depth
Gage
Reading
Correction
Factor
Flexural
Strength*
Average
Strength*
* in lb/square inch.
Field Engineer __________________________________ Date ____________________
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#4 HARDNESS TESTING
Objective
1.
Learn how to determine the hardness of a metal.
2.
Study and practice the relevant standards and equipment operation.
Introduction
Definitions:
There is no such thing as Absolute Hardness or a precise definition of Hardness. The Hardness of a material is
generally defined to be the resistance to plastic surface deformation. Hardness is not a simple property; it
depends on a complex combination of other properties of the material. Furthermore, different kinds of
Hardness tests measure different criteria. Thus, there is only an approximate correlation of Hardness values
between different kinds of Hardness tests. All Hardness measurements must indicate the test used.
Application:
One of the most important properties of materials, especially structural materials, is tensile strength. There is
a correlation between Hardness and tensile strength, as they both are measures of resistance to plastic
deformation. Tests to determine tensile strength are relatively time consuming, costly, and destructive,
whereas Hardness tests are quick, simple, inexpensive, and generally considered non-destructive. Therefore,
Hardness tests are used extensively as a guide to tensile strength. The amount of heat treatment is often
specified in terms of Hardness values. Hardness measurements are widely used for material quality control.
Commonly used Hardness Tests:
Mohs Test:
In general, a relatively hard material will scratch a softer material. The Mohs scale of Hardness is a
semi-quantitative scale designed on this basis. The following series of minerals is used with Hardness values
from 1 to 10 in order of increasing Hardness:
1. Talc
2. Gypsum
3. Calcite
4. Flourite
5. Apatite
6. Orthoclase
7. Quartz
8. Topaz
9. Corundum
10. Diamond
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Dablo Valley College
The units of scale are not equally spaced by any criteria. A substance that will scratch quartz but not topaz,
for example, has a Mohs Hardness of 7-8. When specimens of this series are not available, it is convenient to
know that the steel blade of a pocket knife is 5-6, a copper penny 3-4, and the thumbnail 2-3, in this scale.
The Mohs Test was developed and is used mostly by geologists. While it is good for its purposes, it is not
nearly precise enough for modern commercial applications.
File Test:
An "experienced person" can make a reasonable estimate of the Hardness by the way a piece of metal "feels"
when it is filed. This is of very little commercial value because it is not that precise, cannot be standardized,
and is completely depends on the ability, experience, and the judgment of the "operator".
Spencer-Biergaum Micro-character Test
In this test, the width of the scratch produced by the corner of a diamond cube acting under a 3-gm load is
measured. Because a small indentation is produced, this test can be used to determine the Hardness of
individual grains, or crystals, of the material tested.
Shore Schleroscope Test:
A diamond-tipped "dart" is dropped from a standard height onto the specimen: some energy will be
absorbed in plastic deforming the surface, and the rebound height is a measure of the remaining energy.
The scale is linear with the rebound height - a rebound of 90% of its original height corresponds to a Hardness
of 100 on the arbitrary scale.
This method is fast, the equipment is portable, and the test hardly mars the surface of the specimen.
However, the result correlates more closely with modulus of elasticity than with tensile strength.
Brinell Hardness Test:
In this test the smooth flat specimen surface is indented with a 10 mm diameter steel ball under a load of 500
kg for soft metals and 3000 kg for the rest. The load is maintained for a standard time period, usually 10
seconds. The indentor is then removed and the diameter of the permanent impression is measured by a
low-power microscope. The Hardness values are computed from the mean of two diameter measurements at
right angles. The Brinell Hardness number is obtained by dividing the load (F) by the surface area of the
indentation.
Brinell Hardness Number
=
𝐹
√(𝐷2 − 𝑑2 ) )
𝜋 (𝐷
2 ) (𝐷 −
Where
F = applied load in kg
D = diameter of ball in mm
d = diameter of indentation in mm
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Dablo Valley College
In Brinell Hardness measurement the indentation mark is quite large so the finished products may get
damaged.
For the Brinell test a specimen should be flat and securely supported. The specimen must be thick enough
so that no bulge appears on the opposite face during penetration by the ball and should preferably be ten
times as great in thickness as the depth of the impression. Impressions should not be made within
two-and-one-half diameters of the specimen edge and should be at least five diameters from other test
impressions. The 500 kg load should be applied for a period of at least 30 seconds and the 3000 kg load for at
least 15 seconds.
The Rockwell Test (A, B, C1*)
The Rockwell test is more rapid and leaves a smaller and less conspicuous indentation on the specimen than
does the Brinell test. In the Rockwell test the Hardness value is an arbitrary number that is inversely related
to the depth of the indentation which results from plastic deformation of the material being tested.
The test surface should be flat and free from scale, oxide films, pits and foreign material that may affect the
results. A pitted surface may give erratic readings, owing to some indentations being near the edge of a
depression. This permits a free flow of metal around the indenting tool and results in a low reading. Oiled
surfaces generally give slightly lower readings than dry ones because of the reduced friction under the
indenter. The bottom surface should be free from scale, dirt, and other foreign material that might crush or
flow under the test pressure and so affect results.
To minimize the effects of surface irregularities, the initial setting (Set) of the scale is made after a minor load
(10 kg) is applied to preset the indentor into the specimen. The scale reads from 0 to 100 in units of 0.002mm
and is graduated in a direction such that the greater the penetration the lower the reading.
AB = Depth of hole made by minor load.
AC = Depth of hole made by minor and major load.
CD = Elastic recovery when major load is removed, does not enter in Hardness reading.
BD = Plastic deformation due to major load, which is related to the Rockwell Hardness number.
The load and the design of the penetrator used depend on the kind of material under study. For hard
materials a diamond (Brale) indentor and a 150 kg major load are commonly used (Rockwell C scale). For
softer material a 1/16" steel ball penetrator and 100 kg load are commonly used (Rockwell B scale). A
number of other scales are used for special purposes. For testing surface hardened materials or thin samples
a superficial Hardness tester uses units of 0.001 mm.
The initial setting (Labelect SET) of the dial is at "0" on the black scale, for the Brale indentor, and at "30" on
the red scale, for the ball indentor.
If the 1/16" ball indentors are used with samples harder than Rockwell B 100 they become flattened and give
incorrect readings; if the samples of Hardness lower than RB = 0 are tested with the 1/16" ball and 100 kg
load, the chuck may contact the sample. The specimen must be carefully supported in the Rockwell test
By weight difference; B = 100 Kg, C = 150 Kg
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because any unrecovered vertical motion will change the apparent Rockwell Hardness by one unit for every
0.002mm displacement.
Digital Hardness Tester Instructions
1. Select the appropriate penetrator.
2. Select appropriate load by turning the knob on the right side of the tester away from yourself.
a. 60 for HRA
b. 100 for HRB
c. 150 for HRC
3. Select appropriate Hardness Test using the digital display.
a. Push the Scale button.
b. Scroll to your choice.
c. Press OK.
d. Continue to press OK to navigate through the settings, scroll up or down to select desired
settings.
4. Place the specimen on the support.
5. Turn the support upwards until contact is initiated
6. Apply pressure until the display meter enters the OK region and turns green. If you overshoot the mark,
the meter will turn red. To correct, simply lower the support and reinitiate contact.
7. Once the display meter has entered the OK region and turns green, release and let the machine take
over. It will perform the test without any additional input from you.
8. Once the test has been completed, lower the specimen, alter its position, and repeat the process to
perform another test.
9. To clear previous readings press the Back button.
a. To delete a single reading select “LAST READING” and press OK.
b. To delete all readings select “ALL READINGS” and press OK.
Diamond Pyramid Indentor Hardness Tests (Vickers and Knoop)
The Vickers Hardness tester is similar to the Brinell tester except that it employs a diamond pyramid indentor
of square base. The shape of the cross section of the impression made by this indentor is independent of the
depth of penetration. The Vickers tester can be used to test a much wider range of Hardness than the Brinell
or Rockwell testers, but it is slower than the Rockwell tester and is primarily for research rather than the
production control or commercial testing.
The Knoop tester is a superficial Hardness tester that is similar in principle to the Vickers tester.
Vickers Knoop
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Dablo Valley College
Equipment and supply
1.
Rockwell Hardness Tester
2.
Shore Schleroscope Hardness Tester
3.
Test Specimens - Selected from:
a. C.R. Steel
b. 2024 Aluminum
c. Glass
d. Rubber
e. Wood, a long grain, cross grain
f.
Other available materials
Procedure
1.
Study the instruction for the Rockwell tester.
2.
Make Rockwell and Schleroscope Hardness Tests of each assigned specimen as follows:
a. Make 3 readings spaced at least 1/8" apart
b. Make 5 readings at the same location
c. Measure the Hardness as close as possible to one of the previous test sites on the steel
specimen
d. Check the Hardness close to the edge of the steel specimen
Report (required content)
1.
How do conversion between Rockwell and Schleroscope Hardness value compare? Explain.
2.
What happens when successive Hardness tests are made at the same location? Why?
3.
What factors might cause erroneous readings? What precision or repeatability might be expected?
4.
How would the Hardness values be affected for very thin specimens?
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CLARK ROCKWELL HARDNESS TESTER
1.
Estimate the characteristics and probable Hardness of the test sample.
2.
Select the penetrator, load, and scale to be used. When in doubt use the Rockwell C scale.
3.
Install the proper penetrator on the machine.
4.
Install the proper weight on the machine.
5.
Install the appropriate anvil on the machine.
6.
Insert the test sample.
7.
Apply the minor load. Turn the elevating screw so that the dial gage turns three full revolutions.
UNDER NO CIRCUMSTANCES SHOULD THE CAPSTAN BE TURNED IN REVERSE TO BACK UP A DIAL
HAND THAT HAS TRAVELLED TOO FAR PAST THE VERTICAL RED LINE.
8.
Adjust the dial gage to zero.
9.
Apply the major load. Push the loading handle away from you with an easy twist of the fingers.
10. Remove the major load after the dial gage stops moving.
11. Read the dial gage and record the Hardness-letter and number.
12. Release the minor load, and remove the test sample.
13. Return the parts and cover the tester.
SCALE
A
B
C
D
E
F
G
H
K
L
M
P
R
S
V
DIAL FIGURES
Black
Red
Black
Black
Red
Red
Red
Red
Red
Red
Red
Red
Red
Red
Red
PENETRATOR
"C" Diamond
1/16" Ball
"C" Diamond
"C" Diamond
1/8" Ball
1/16" Ball
1/16" Ball
1/8" Ball
1/8" Ball
1/4" Ball
1/4" Ball
1/4" Ball
1/2" Ball
1/2" Ball
1/2" Ball
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LOAD (Kg)
60
100
150
100
100
60
150
60
150
60
100
150
60
100
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Common Rockwell Hardness testing scales and configurations
Scale
A (HRA)
B (HRB)
C (HRC)
N (HRxxN)
L (HRL)
Condition
Brale Indenter
60kgf load
1/16” Steel Ball
100kgf load
Brale Indenter
150kgf load
Superficial Brale Indenter
15, 30, 45kgf load
1/4” Steel Ball
60kgf load
Application
Cemented Carbides, Thin hard sheet
materials
Medium/low Hardness materials (Al, Cu,
Fe, Annealed Carbon Steels)
Materials harder than HRB 100
Materials with surface Hardness
gradients, very thin sections
Soft polymeric samples
Rockwell Hardness testing minimum thickness requirements
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Brinell
(10 mm Ball, 3000 kg load)
Vickers
(120 kg)
Rockwell C
(120 degree cone 150 kg)
Rockwell B
(1/16" ball 100 kg)
800
-
72
-
780
1220
71
-
760
1170
70
-
745
1114
68
-
725
1060
67
-
712
1021
66
-
682
940
65
-
668
905
64
-
652
867
63
-
626
803
62
-
614
775
61
-
601
746
60
-
590
727
59
-
576
694
57
-
552
649
56
-
545
639
55
-
529
606
54
-
514
587
53
120
502
565
52
119
495
551
51
119
477
534
49
118
461
502
48
117
451
489
47
117
444
474
46
116
427
460
45
115
415
435
44
115
401
423
43
114
388
401
42
114
375
390
41
113
370
385
40
112
362
380
39
111
351
361
38
111
346
352
37
110
341
344
37
110
331
335
36
109
323
320
35
109
311
312
34
108
301
305
33
107
293
291
32
106
285
285
31
105
276
278
30
105
269
272
29
104
261
261
28
103
258
258
27
102
249
250
25
101
245
246
24
100
240
240
23
99
237
235
23
99
229
226
22
98
224
221
21
97
217
217
20
96
211
213
19
95
206
209
18
94
203
201
17
94
200
199
16
93
196
197
15
92
191
190
14
92
187
186
13
91
185
184
12
91
183
183
11
90
180
177
10
89
175
174
9
88
170
191
7
87
167
168
6
87
165
165
5
86
163
162
4
85
160
159
3
84
156
154
2
83
154
152
1
82
152
150
-
82
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#5 TENSILE TEST
Objectives:
To learn and practice the standard method of tensile test.
Introduction:
Tensile test determines the strength of the material when subjected to a simple stretching operation.
Typically, standard dimension test samples are pulled slowly at a uniform rate in a testing machine while the
strain is defined as:
Engineering Strain = Change in Length / Original Length
The engineering stress is defined as:
Engineering Stress = Applied Force / Original Area
Modulus of Elasticity: The initial slope of the curve, related directly to the strength of the atomic bonds. This
modulus indicates the stiffness of the material. (Modulus Elasticity is also known as Young's Modulus)
Modulus of Elasticity = E = Change in Stress/ Change in Strain
Yield Strength: The stress at which plastic deformation begins.
Tensile Strength: The maximum stress applied to the specimen. Tensile strength is also known as Ultimate
Strength. (The highest point on the stress-strain diagram)
Percent Elongation: The maximum elongation of the gage length divided by the original gage length.
𝑙𝑓 − 𝑙0
%𝐸𝐿 = (
) × 100 = (strain at yield − strain at fracture) × 100
𝑙0
During this experiment you will be given a piece of metal that will act as your sample. You will place your
sample in the tensile test machine, measure the distance between the grips (jaws), and then use the
machine to stretch your sample until it breaks in two. Following this, the machine will provide you with a
data set that will allow you to create a stress vs. strain graph. From this graph you will be able to determine
values for Modulus of Elasticity (Young’s Modulus), Yield Strength, Ultimate Tensile Strength, and Percent
Elongation.
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Presented below is a sample graph:
Equipment & Supply
1. A metal specimen for testing (provided by your instructor).
2. A flash drive.
3. A ruler.
Safety Precautions
The operation of this machine is not intuitive. These instructions contained in this manual are intended
as a supplement to verbal instruction, not as a substitute for it. Before proceeding with a test make sure that
someone who knows how to use the tester has explained its operation to you.
Procedure for Performing a Tensile Test:
1. Obtain your sample.
2. Use a pair of calipers to measure the cross-sectional area of your sample. Be sure to take your
measurement at the middle of your specimen. This is the part of the sample that we are testing. The
wider upper grips are simply being used to hold the specimen in place.
3. Undo the red Emergency Stopper by turning it clockwise and pulling it towards you.
 At any point the test can be stopped by turning the emergency stopper inward.
Make sure you understand how this works before proceeding.
4. Turn the machine power on. (One switch in back and one switch on bottom right of front)
5. Calibrate the tester. (This must be done every time the machine is turned on. If the machine is
already up and running you may skip this step, no calibration between tryons.)
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



Press the system button.
Press start when “Calibration” appears, press start again to select force, press start
again to select execution.
Allow the calibration to reach completion and press Test when done.
Log into the Trapezium software(User:admin Password:admin) using the computer to
the right of the machine.
Pre-Test
1) Upon opening the homepage of Trapezium, you should see several preloaded methods that
have been prepared in advance.(Each test is performed within a method.) Go to
File>New>Method (and set up as new method.)If you are performing a second test and the
appropriate method has already been selected jump down to 2. Otherwise, continue reading.
a. Select “Tensile Test.xmas”
b. Double click on the method to open it.
2) Once the test screen opens select the “Specimen Sizes” option on the lower left side of the
screen.
a. From here you will be able to enter the dimensions of your specimen.
b. Measure the thickness, depth and the gage length of the specimen and enter the
relevant information.
c. Upon entering the information you should be returned to the previous screen.
Post-Test
1) Once the test has reached completion you will want to save your data.
a. Select File, Export, Raw Data.
b. This will create an Excel file containing your data. Name the file and save it.
2) Minimize the program and open the “Exports” folder on the home screen.
a. Look for your file and open it to verify that all of your data has been correctly
transferred.
b. Close the file and save it to a flash drive.
3) Return to the program to ready it for another test.
a. Select File, New, Test.
The program is now ready to perform an additional test.
6. Place the specimen in the upper grip.
 Insert the specimen up to the etched line and tighten the upper grip lever so that it is
firmly in place.
7. Lower the specimen.
 Turn Jog on.
 Press High Speed.
 Push the down arrow (to the right of Jog) to lower.
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 Lower the specimen until the bottom of it reaches the etched line.
 Press High Speed again (switches it off).
 Press Jog again (to turn it off).
 Tighten the lower grip lever so that the specimen is firmly in place.
8. Measure the distance between the upper and lower grip (you want to measure how much of
the sample is exposed). As we are only interested in the portion of the sample being stretched,
this will be considered the original length of your specimen.
9. See software instructions for further information.
10. Zero Hold
 Press the Test button (nothing will happen if selected properly.).
 Press Force Zero Hold. This will set the force reading to zero.
 Once the reading is sufficiently close to zero, press Stop.
11. Begin the test.
 Press the Start button.
 The tester will ask you to confirm that you wish to begin. To do so, press the Start
button again.
12. Allow the test to reach completion.
13. Remove the specimen.
 Raise the specimen using the process described in step 6.
 Loosen the grips to remove the specimen.
14. You can now use the software to evaluate your data and save your results.
 Once again, refer to the software instructions.
15. To ready the program for another test select Test, then select Next Test.
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Tensile Machine Software Instructions (Trapezuim)
Pre-Test
3) Upon opening the homepage of Trapezium, you should see several preloaded methods that
have been prepared in advance.(Each test is performed within a method.) Go to
File>New>Method (and set up as new method.)If you are performing a second test and the
appropriate method has already been selected jump down to 2. Otherwise, continue reading.
a. Select “Tensile Test.xmas”
b. Double click on the method to open it.
4) Once the test screen opens select the “Specimen Sizes” option on the lower left side of the
screen.
a. From here you will be able to enter the dimensions of your specimen.
b. Measure the thickness, depth and the gage length of the specimen and enter the
relevant information.
c. Upon entering the information you should be returned to the previous screen.
Post-Test
4) Once the test has reached completion you will want to save your data.
a. Select File, Export, Raw Data.
b. This will create an Excel file containing your data. Name the file and save it.
5) Minimize the program and open the “Exports” folder on the home screen.
a. Look for your file and open it to verify that all of your data has been correctly
transferred.
b. Close the file and save it to a flash drive.
6) Return to the program to ready it for another test.
a. Select File, New, Test.
b. The program is now ready to perform an additional test.
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#6 TOUGHNESS
Objectives:
1.
To learn the standard method of the Charpy V-notch impact test.
2.
To observe the influence of temperature and heat treatment on the toughness of steel.
3.
To experiment the stress concentration caused by a sharp notch.
Introduction:
The mechanical properties of materials can be divided into three groups: elastic properties, plastic
properties and fracture properties. Each group has a different set of structural dependencies. Elastic
properties (Moduli of Elasticity & Shear) depend on atom to atom bonding forces. Plastic properties
(Strength, Hardness & Ductility) depend on the defect (i.e. dislocation) structure. Fracture properties
(Toughness) depend on the gross microstructure, including chemical composition. Likewise, temperature
influences each group differently. The Modulus of Elasticity drops less than 10% for steel going from -200oC to
100oC, while its Yield Strength drops about 50% over that same range of temperature. This experiment
examines the effect of temperature on the toughness (fracture properties) of steel.
Material brittleness is characterized by fracturing under low-energy impact and is proportional to the area
under the stress-strain curve which is called Toughness. The tough steel is generally ductile and requires a lot
of energy to cause failure. The brittle steel does not deform very much during a failure and does not require
much energy to initiate.
The most common method of characterizing the Roughness of a material is the notched bar impact test. By
subjecting a specimen to an impact load, it will fail if the load exceeds the breaking strength of that material.
By using a swinging pendulum to impart the load, the energy required to fracture the specimen can be
determined by measuring the height the pendulum swings after the fracture.
This test has been used extensively with body-centered-cubic (BCC) crystalline materials. Only BCC materials
show a markedly abrupt transition from ductile to brittle with decreasing temperature. This means that at
low temperatures the fracture energy is low. Very often BCC materials are ductile at normal temperatures,
until they are heat treated.
The ductile/brittle transition temperature corresponds to a fracture appearance consisting of 50% shear and
50% cleavage. A cleavage fracture is characteristic of brittle failures. The cleavage surface has a shiny granular
appearance and is usually perpendicular to the specimen. A shear fracture is characteristic of ductile failures.
The shear surface is dull, deformed, fibrous, and contains shear lips which are not perpendicular to the
fracture surface.
The nil-ductility temperature, NDT, is the minimum temperature displaying shear fracture; corresponds to the
junction of the lower "shelf" with the upward sloping "transition" curve.
Fracture testing is complex because of the three factors:
1. strain rate (slowly applied or at high velocity)
2. stress state (notched or un-notched)
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3. temperature (sub-zero or elevated)
The ductile/brittle transition temperature may vary as much as 200 oF in such as stress system. Many factors
such as grain size, alloy content, Carbon content, root radius of the notch, heat treatment, and fabrication
methods (cast or forged) affect this transition temperature.
Heat Treatment of Steels
Steels which are really solid solutions of Iron and Carbon are BCC material. However, the Carbon has a low
solubility in Iron as BCC and precipitates as Iron Carbide (cementite) when the steel is cooled from 1600oF.
The process of precipitation can be altered by adjusting the cooling rate. This changes the distribution and
size of the carbide which forms the lamallar structure pearlite during the slow cooling process.
If a steel is quenched into water or oil from 1600 oF, the meta-stable phase martensite forms, which is
body-centered-tetragonal. This phase sets up large internal stresses and prevents pearlite from forming. The
internal stresses produce high Hardness and, unfortunately, low toughness.
After cooling, to restore toughness, steels are tempered by reheating them to a lower temperature around
800oF (depending upon the steel composition) and cooling. The tempering relieves the internal stresses and
also allows some Iron Carbide and Ferrite to form.
Notched-bar Impact Tests
Although the notched bar often provides tri-axial stress components high enough to induce brittle failure in
steels, no satisfactory method has ever been devised for measuring or computing the stress components in
notched bars. There are convincing indications that a given geometry of notch does not impose the same
stress system when used with different materials.
For this reason, it is evident that the data from the notched-bar test are subject to limited interpretation.
The test can be expected to indicate only that a steel is or is not brittle when tested at a given temperature
with a notch of given form and severity. When interpreted within these limitations the comparison of results
from one material with those from other materials can lead to a useful estimate of quality or to a correlation
with the properties of other materials of supposedly similar composition. However, the limitations should
be kept clearly in mind, and the test should not be misused. It should be further noted, that while this is an
impact method for determining energy absorption, it is NOT a test of shock behavior.
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Types of Specimens
In this country, two types of test specimens were developed: the Standard Charpy Specimens and the
Standard Izod Specimen. However, the most common specimen is a combination of a Charpy type with the
Izod notch. This is known as the "V-notch Charpy specimen" (Fig. 12.1)
This lab is for finding the toughness vs. temperature curve for a given structural steel. The transition zone
should be determined and the ductile/brittle transition temperature and the nil-ductility temperature should
be derived.
We will also compare these results with some specimens that have been hardened (quenched) or tempered
(quenched and tempered).
Due to the number of specimens required and their cost, this will be a class project. Each lab group will test
one or two specimens and the results will be shared with the other groups. Each specimen will be treated for
different conditions.
Fig. 12.1
Equipment & Supply
1. Temperature bath supplies
a. Liquid Nitrogen
b. Dry Ice
c. Alcohol
d. Hot Oil
e. Boiling Water (Bunsen Burner)
2.
Potentiometer
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3.
Charpy Impact Machine
4.
Tongs & gloves
5.
Charpy specimens
6.
Furnace
7.
Stereo Microscope
Safety Precautions
The Charpy Impact Machine can cause serious injury. Nobody is ever to be in the path of the pendulum.
Safety Latch (Fig 12.2) should be activated until ready to release the pendulum. Have a team mate hold the
pendulum until releasing. Use tong to insert specimens and to remove broken specimens. The person loading
the specimen should be the "trigger-man" who pushed the knob to release the pendulum.
Liquid Nitrogen, dry ice, hot oil, and boiling water can cause
serious burns.
Learn the proper way to operate it before using the impact machine.
Always take great caution to avoid accidents.
Fig. 12.2
Procedure
1.
Determine which conditions your group is to test.
2.
Reread the safety precautions.
3.
If required, perform heat treatment by heating specimens for 30 minutes at 1650 oF and quenching
into a bucket of water.
4.
If required, temper quenched specimens by heating for 30 minutes at 800 oF and quenching again.
5.
Conduct the impact tests under the following conditions, recording data on data sheet:
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a. liquid Nitrogen or dry ice in alcohol
-50oC
b. ice–water
0oC
c. hot water
50oC
d. boiling water
100oC
e. oven
200oC
f.
Quenched specimen - room temp.
25oC
g. Tempered specimen - room temp.
25oC
Use additional specimens to get intermediate data to more fully define the toughness curve and the
transition temperature.
Soak specimens 8-10 minutes in temperature bath to reach bath temperature.
same temperature.
Keep tongs at the
Specimens should be tested within 5 seconds after removal from bath. Set the temperature bath on
the floor to facilitate quick transfer. Position the specimen accurately, quickly, and SAFELY with the
tongs furnished. A few dry runs is recommended to practice inserting the specimen into position
before actual execution.
Measure the bath temperatures. A few degrees deviation in temperature will not alter the results if
actual temperatures are recorded.
6.
Examine the fractured surfaces for the fracture appearance graph - use binocular microscope.
7.
Save, tape together, and mark the temperature and energy on the broken specimens for future
reference.
8.
Recycle the used alcohol - pour it back in the bottle, unless otherwise instructed.
Graphs (required content)
1.
Prepare energy vs. temperature curve.
2.
Prepare fracture-appearance (shear %) vs. temperature curve. Label transition temperatures on
each graph.
Discussion (required content)
1.
Specify:
a. Transition temperatures based on energy and also based on fracture appearance.
b. Nil-ductility temperature.
c. Charpy 15 ft. - # Temperature (Arbitrary minimum for ship's steel)
2.
What effects does heat treatment have on impact properties?
3.
What are possible reasons for statistical variations in the results.
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CHARPY TOUGHNESS DATA SHEET
TESTER
DATE
MATERIAL
HEAT
TREATMENT
52
TEST TEMP.
FRACTURE
ENERGY
FRACTURE
SURFACE
% SHEAR
Dablo Valley College
#7 METALLURGY TECHNIQUES
CUT OFF MACHINE
Operation Instructions
1.
Select the proper wheel for the material.
2.
Lock wheel firmly on arbor using wrench and pin provided. Pin fits hole in flange fixed to arbor.
3.
Lock the sample in place by twisting the vise handle. Lock sample in such a way that there will be no
movement during or on completion of the cut.
4.
PUT ON FACE SHIELD.
5.
Turn on motor.
6.
Adjust coolant flow. Use as much coolant as possible without excessive spray.
7.
Push up on vise handle to cut. Do not press hard enough to slow motor. This cutter is intended for
samples of 1/2-inch diameter or less.
8.
Turn off motor when cut is finished.
9.
Turn off water.
10. Remove specimen.
Selection of Wheels
Cut-Off wheels consist of an abrasive, bonded with rubber or plastic. As the wheel cuts, the abrasive is dulled.
The bonding material must then break down to free the dulled abrasive and allow new sharp particles to cut
the specimen. In choosing a wheel for any cutting job, it is most economical to choose the hardest bonded
wheel which will cut the material satisfactorily. The softer the bonding material in the wheel, the less time it
will take to break down and to wear out.

No. 1121 Abrasive Wheels
#416 Hard Bonded Wheels for cutting soft to medium hard ferrous materials
#296 Medium Wheels for general use where most cuts are on hardened materials.
#481 for cutting extremely hard materials.
#KA46 for dry cutting of small parts.

No. 119 Diamond Wheel
For brittle materials such as glass.
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Dablo Valley College
Lubrication
Grease motor every 6 months. Remove motor cover, remove grease plugs at each end of motor and insert
grease fitting and gun. Use ball bearing grease. Put a few drops of oil on axis of carriage, movable jaw and vise
nut.
No. 1305-2 AB Centermet Press
Operation Instructions
1.
Clean mold and check to see that male members fit into mold cylinder freely.
2.
Place the bottom male mold member in the bottom of the mold cylinder. DO NOT FORCE
3.
Place the specimen, flat surface down on the bottom male mold member.
4.
Pour one measure of Bakelite molding powder into mold.
5.
Insert the top male member into the cylinder.
6.
Place the automatic heater in lowered position over the ram.
7.
Turn on heater.
8.
Place the mold assembly on the mold carrier.
9.
Rotate the cam so that it blocks the ejection aperture.
10. Raise the ram using the pump handle until the top of the mold assembly touches the cam.
11. Raise the heater and hold it in place with heater support pin.
12. Set heating timer for 9 to 12 minutes.
13. Increase pressure to 4200 PSI. (red dot marked 1 1/4")
14. Hold pressure on red dot until timer rings, (pressure will tend to drop in 4 minutes after heating
started).
15. Release pressure, turn off and remove heater. Put cooler on for 5 to 10 minutes.
16. Remove cooler and rotate cam away from ejection aperture.
17. Close pressure valve and pump top male mold member, mounted specimen, and bottom mold
member from the mold cylinder.
18. Lower ram.
19. Remove mold cylinder.
20. Clean mold.
21. Clean press and bench.
22. Return supplier and equipment to their proper locations.
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20-1320 SimpliMet II Mounting Press
Operation Instructions
1.
Raise the handles and remove the cylinder closure as needed (set zero pressure.)
2.
Raise the ram to the top edge of the mold cylinder wall by turning the knob clockwise to full closure
and operating pump handle
3.
Place the specimen in the center of the ram face
4.
Lower the ram by turning the knob counter-clockwise to release the pressure
5.
If Bakelite molding compound is not used, using a funnel to add ~ 30 ml mold powder.
6.
Replace the cylinder closure by hand; finger-tighten it in clockwise direction until threads are fully
engaged. DO NOT APPLYING EXCESSIVE FORCE.
7.
Apply half pressure.
8.
Release the pressure.
9.
Reapply 2 ram force units more than the recommended pressure.
10. Maintain pressure for ~ 10 minutes. No monitoring required.
11. Grasp the two handles firmly and jerk gently while turning in counter-clockwise direction to remove
the closure. Continue turning until the closure is off; actuating the bottom ram upward as needed.
12. Remove the mounted specimen.
NOTE: Keeping the press clean is very important. A buildup of mounting
compound residue can seriously affect the performance of the press,
generally either causing the ram to stick in the cylinder, with
your specimen, or making it difficult to open and close the cylinder.
Cylinder Closure
Cooling Collar
Pressure Pump Handle
Pressure Valve Control Knob
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PREPARATION OF METALLURGICAL SPECIMENS
Sample Preparation
1.
File cross-section with fine file to get smooth surface.
2.
Peel away adhering filings.
Mount Sample
1.
Mount sample in Bakelite by using 1305-2 AB Centermet Press.
2.
Label sample with engraver.
3.
Record sample identification in record book.
Polish Sample
1.
Sand the sample surface with fine sandpaper.
2.
Clean the sample by washing or by blowing with air hose.
3.
Rotate sample 90o and sand with #1 sandpaper until scratches from the first sanding are no longer
visible.
4.
Clean the sample with water.
5.
Rotate sample 90o and sand with #0 sandpaper until all prior scratches are no longer visible.
6.
Clean the sample.
7.
Rotate 90o - Sand with #2/0 sandpaper.........
8.
Clean the sample.
9.
Rotate 90o - Sand with #3/0 sandpaper........
Do not overheat.
10. Clean the sample.
11. Rotate 90o - Sand with #4/0 sandpaper .......
12. Clean the sample with alcohol.
13. Polish with coarse (#1) alumina. (5.0 microns)
14. Wash with water, soap and alcohol; dry with blower to prevent staining.
15.
Polish with fine (#3) alumina (.05 microns).
16. Wash sample with water, soap, and alcohol.
17. Etch.
18. Wash sample with water and alcohol; dry with blower.........
19. Examine sample with microscope.
20. If scratches are still present, go back to step 14.
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Etching Reagents
Etchant Composition Conc. Conditions Comments
Material
Iron & Steel
General
Low Carbon
Welds
Wrought Iron
Malleable Iron
Martensite
Stainless
Austenitic Stainless
Reagent
Composition
Remarks
5% Nital
2% Nital
2% Nital
2% Nital
2% Nital
2% Nital
Aqua Regla
Aqueous Ferric
Chloride
5% HN03 in ethyl alcohol
2% HN03 in ethyl alcohol
2% HN03 in ethyl alcohol
2% HN03 in ethyl alcohol
2% HN03 in ethyl alcohol
2% HN03 in ethyl alcohol
75% HCL, 25% HNO3
Dip 10-30 sec.
Dip 10-30 sec.
Dip 10-30 sec.
Dip 10-30 sec.
Dip 10-30 sec.
Dip 10-30 sec.
Swab 10-30 sec.
5g FeCl3, 50cc HCl, 100cc H2O
Swab 10-30 sec.
4% HN03, 96% amyl alcohol
Dip 5 min.; Colors
austenite Yellow, Martensite
White, Tempered structure
Brown
Stainless
Heat Treated Steels
Copper, Brass,
Bronze
Nickel 8. Nickel Alloy
Marble's Reagent
4g CuSD4, 20cc HCl, 20cc H20
Ferric chloride
5g FeCl3, 10cc HCl, 100cc H2O
10g FeCl, 5cc HCl, 200cc Ethyl
alcohol
25% H3PO4, 25% ethyl alcohol,
60% H2
Alcoholic Ferric
Chloride
Merica’s Reagent
Keller's reagent
Aluminum
Sodium hydroxide
Hydrofloric acid
Zinc & Zinc alloys
Antimony & Bismuth
for electropolish/ etch
Swab 10-15 sec.
Swab 10-15 sec.
1% HF, 1.5% HCl, 2.5% HN03, 95%
H20
1% in water
0.5% in water
50%. HCl, 50% H20
Swab 5-15 sec.
Swab 5-15 sec.
Can also be used more dilute
5% HN03, 95% H20
for electropolish/etch
90% Glycerol, 5% Acetic and 5%
HN03
Lead & Lead alloys
Tin & Tin alloys
Swab 5-15 sec.
2% Nital
2% HN03, 98% ethyl alcohol
5% AgN02, 95% H20
Also suitable for alloys of Lead
& Tin
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UNITRON - METALLURGICAL MICROSCOPE
Set Up (as needed)
1.
Remove microscope from box.
2.
Place Binocular Body on microscope Part #Bi - 6613 - along with desired eyepiece.
3.
Place Illuminator Condenser unit on microscope body and plug in bulb.
4.
Place circular stage plate Specimen Holder and specimen on top of mechanical stage.
5.
Plug in turn on low.
Operational Procedures
1.
Lower the stage as far as it will go using the Coarse focus control. Center the mechanical stage.
2.
Adjust fine focus so as to position the movable index approximately midway between the fixed scale
lines.
3.
Rotate the nosepiece to place the desired objective in the optical path, making certain the click stays
engages.
4.
Make sure the path selector slideway is all the way to right (for observation only) PSS is below
objectives.
5.
Observe the lamp alignment mirror (to right of objectives).
6.
Adjust light bulb for maximum brightness on mirror (adjusting screws are provided on light bulb
unit).
7.
Image should be visible. Adjust fine focus for clarity.
Carbolyte Oven Instructions
1) Power on the oven.
2) If you want the oven to go to the preset temperature, leave it alone and it will do just that. The oven
will automatically display its current temperature and you will be able to see when it has reached the
desired setting. Be advised that the oven will often go past the desired temperature before coming
back down and settling on it.
3) Checking the temperature setting.
a. Press the Home Button (bottom left button).
b. SP°C will appear.
c. Press either the up or down arrow (one time) to view the temperature setting.
d. When done press the Home Button until the current temperature appears on the screen.
4) Changing the temperature setting.
a. Press the Home Button (bottom left button).
b. SP°C will appear.
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c. Press either the up or down arrow (one time) to view the temperature setting.
d. Use the up or down arrow to change the setting.
e. Once the desired setting has been reached you do not need to push anything else, that
temperature will automatically be set.
f. When done press the Home Button until the current temperature appears on the screen.
5) Setting Ramp Time.
a. Press the Home Button (bottom left button) until SPrr appears.
b. Use the up or down arrow to change the setting.
c. Once the desired setting has been reached you do not need to push anything else, that ramp
time will automatically be set.
d. When done press the Home Button until the current temperature appears on the screen.
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PHOTOGRAPHING METALLURGICAL SPECIMENS
WITH THE UNITRON POLAROID CAMERA
You may use your own phone/camera to take a photo through the lens of the microscope.
General Information
The Unitron camera utilizes the Polaroid land film pack (B & W) 3000 speed type 107. See directions with film
for cleaning and loading. The camera lens has divisions of 0.1 mm and a magnification of 10X.
Operation Instruction
Turn light source on (located bottom right) and focus specimen. Adjust the field diaphragm (F.D.) to the
area to be photographed and the AP for a normal light setting. With the shutter speed set to 30 and the
shutter clutch engaged push sideways selector left and press extended-shutter button. Remove film by
pulling white tab forward to expose black tap then pull black tab to remove exposed picture. Wait at least
15 seconds before removing developing paper and coat immediately with coating apparatus provided with
film pack.
As an aid in determining the size of any object on the picture, the following data is provided.
Objective Lens Selection
Magnification
100 X
(oil immersion)
40 X
10 X
5 X
Division
Scale
.0010 mm
0.05 mm
.0025 mm
.01 mm
.02 mm
0.125 mm
0.5 mm
1.0 mm
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#8 HEAT TREATMENT OF STEEL
Objective
1.
Learn how to apply heat-treatment to steel material.
2.
Study the properties of a heat-treated steel.
Procedure
1.
Obtain circular sample from the instructor.
2.
Record sample number on data sheet.
3.
Use cut-off machine to divide sample into 4 quarters.
Note:
take care to insure each quarter has a number on it.
4.
Heat all 4 samples to 900 C for 1 of 30 minutes. Record time in and furnace temperature.
5.
The 4 samples are to be treated in the following 4 different ways
a. Quench in agitated water (record furnace temp, time in & out)
b. Quench in agitated water, as above, followed by tempering at 400 C for one hour. Quench.
c. Air cool. Remove specimen from furnace and place on a brick until safe to hand (5 to 10
minutes)
d. Furnace anneal; leave in furnace and allow to cool along with the furnace (3 to 5 hours)
6.
Make Rockwell C Hardness Tests of each specimen.
Note: if the values are too low, it may be necessary to use a different
Hardness scale. For comparison purposes, it is best to use the same
scale for all 4 specimens. The Hardness readings should be done
BEFORE the specimens are mounted, as the mounts may distort the
Hardness readings.
7.
Mount specimens in Bakalite mounts
8.
Polish and etch the specimens.
9.
Examine the specimens under the microscope to determine the structure. Try to determine the
phases present, the amount of each phase, and possibly the relative size of the grains.
Carbolyte Oven Instructions
1) Power on the oven.
2) If you want the oven to go to the preset temperature, leave it alone and it will do just that. The oven
will automatically display its current temperature and you will be able to see when it has reached the
desired setting. Be advised that the oven will often go past the desired temperature before coming
back down and settling on it.
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3) Checking the temperature setting.
a. Press the Home Button (bottom left button).
b. SP°C will appear.
c. Press either the up or down arrow (one time) to view the temperature setting.
d. When done press the Home Button until the current temperature appears on the screen.
4) Changing the temperature setting.
a. Press the Home Button (bottom left button).
b. SP°C will appear.
c. Press either the up or down arrow (one time) to view the temperature setting.
d. Use the up or down arrow to change the setting.
e. Once the desired setting has been reached you do not need to push anything else, that
temperature will automatically be set.
f. When done press the Home Button until the current temperature appears on the screen.
5) Setting Ramp Time.
a. Press the Home Button (bottom left button) until SPrr appears.
b. Use the up or down arrow to change the setting.
c. Once the desired setting has been reached you do not need to push anything else, that ramp
time will automatically be set.
d. When done press the Home Button until the current temperature appears on the screen.
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Specimen Identification
Ladle Analysis
No.
Grade
Deox
Type
C
Mn
P
S
Si
1
1010
Semi-Kil
BOF
.12
.45
.007
.032
.03
2
1020
Killed
OH
.20
.52
.009
.028
.21
3
4
5
6
7
8
9
1035
1045
1060
1080
1095
1340
4130
Killed
Killed
Killed
Killed
Killed
Killed
Killed
BOF
BOF
OH
BOF
OH
BOF
EF
.33
.48
.55
.80
.93
.39
.30
.72
.88
.80
.74
.50
1.65
.58
.018
.013
.012
.023
.009
.010
.007
.025
.025
.023
.014
.030
.025
.007
10
11
4140
4340
Killed
Killed
BOF
EF
.43
.43
.94
.76
.019
.015
12
13
14
15
16
17
4615
5140
8620
8630
8655
52100
Killed
Killed
Killed
Killed
Killed
Killed
EF
EF
EF
OH
OH
EF
.16
.40
.19
.30
.56
1.01
.44
.85
.75
.81
.88
.36
.008
.013
.008
.009
.012
.010
64
Ni
Cr
Mo
.17
.22
.19
.18
.22
.23
.23
.12
1.09
.22
.025
.010
.31
.28
.04
1.78
.99
.77
.20
.27
.029
.025
.012
.020
.019
.009
.30
.30
.29
.26
.23
.27
1.75
.10
.56
.52
.54
.03
.09
.84
.49
.48
.52
1.45
.24
.02
.20
.20
.20
.02
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Heat Treatment of Steel data sheet
Sample Number
Date
Name
Party Members
HEAT TREATMENT
Specimen
IN
OUT
Temp
Time
Temp
Time
TEMPER
IN
Temp
Time
A
B
C
D
Hardness Readings, Scale
Average
A
B
C
D
Microscopic Examination
Phases present
Percent
A
B
C
D
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Comments
OUT
Temp
Time
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#9 PRECIPITATION HARDENING IN ALUMINUM
ALLOY
Objectives
To study the variation in Hardness of an aluminum alloy on isothermal aging.
Introduction
The materials can be hardened by inhibiting the motion of dislocations. In pure metals, the presence of
defects (as vacancies, interstitials, dislocations, and grain boundaries) can enhance the strength. In single
phase alloys, additional resistance to deformation may arise from the presence of solute atoms. In
two-phase alloys, additional stress is needed to enable the dislocation to intersect the second-phase
particles. A finely dispersed precipitate may, therefore, strengthen the material. This phenomenon is
termed precipitation hardening.
In precipitation hardening treatment, the alloy is first solutionized by heating into the single phase region,
held there long enough to dissolve all existing soluble precipitate particles and is then rapidly quenched into
the two phase region. The rapidity of the quench prevents the formation of equilibrium precipitates and thus
produces a supersaturated solid solution. On aging at, or above, room temperature, fine precipitates will
form. If precipitation occurs at an elevated temperature, the process is called artificial aging.
In the present experiment, the precipitation hardening behavior of the aluminum alloy will be studied by
measuring changes in Hardness as function of aging time.
Equipment & Supply
1.
One specimen of Aluminum alloy (2024)
2.
Furnace for heat-treating specimens at 500oC
3.
Water bucket
4.
Hardness tester (Rockwell)
Procedure
1.
Obtain a 2024 aluminum specimen.
2.
Measure the Hardness of the "as received" specimen.
3.
Place the specimen in a furnace at 500oC for 60 minutes. (Solution treatment).
4.
Quench the specimen into water and measure its Hardness immediately.
5.
Age the specimen at room temperature. Measure the Hardness after 10 min., 30 min., 1 hour, 2
hours, 4 hours, 8 hours, 1 day, 2 days and 1 week.
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6.
Make a table of Hardness with respect to time.
7.
Plot Hardness vs. aging time in a semi-log graph.
Discussion
1.
Discuss the variation in Hardness as a function of aging time.
2.
How will the Hardness vs. aging time curve shift for an aluminum alloy with 0.5% more copper?
3.
How will the aging temperature affect the aging time of the specimen?
References
1.
E.C. Subbarao, "Experiments in Materials Science"
2.
H. W. Hayden, W. G. Moffagg, J. Wulff, "The Structure and Properties of Materials", Vol. 3
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BACKGROUND: 2024 ALUMINUM ALLOY
Alloying elements: 4.5% Cu, 1.5% Mg. 0.6% Mn.
Typical Uses: Aircraft structure, rivets, hardware, truck wheels.
A. Solution Treatment:
Solution treatment temperature range 910-930oF.
The exact solution treatment temperature has a significant effect on the properties of the solution
treated material as shown below.
Solution Treatment
(Temperature)
Tensile Strength
(PSI)
Yield Strength
(PSI)
910oF (488oC)
60,800
37,000
o
o
61,300
37,500
o
o
62,800
39,000
o
o
63,900
39,300
915 F (491 C)
920 F (493 C)
925 F (496 C)
Eutectic melting temperature
935oF (502oC)
NOTE:If the eutectic melting temperature of the alloy is exceeded, grain
boundary melting occurs and the material is rendered brittle and
non-salvageable by further heat treatment.
Quenching:
 Must be done without delay - no more than 10 seconds from opening furnace to immersion in
water.
 Must be done in agitated water which is at no more 100oF AFTER completion of quenching.
 If the quench rate is not high enough, corrosion resistance is severely affected.
B. After Quenching, before precipitation.
In some aluminum alloys, such as 2024, cold working of freshly quenched material greatly increases its
response to later precipitation heat treatment. Thus, a controlled amount of rolling or stretching is
often applied immediately after quenching.
C. Precipitation treatment at 370-380oF
Artificial Aging Time
16-18 hours
11-13 hours
7-9 hours
Non cold worked material
1% cold worked
6% cold worked
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D. Age Hardening
At "room temperature" age hardening occurs between 1 day and 1 week.
E. Hardness Tests are of less value for acceptance or rejection of heat treated aluminum alloys than for
steel. Nevertheless Hardness tests are of some utility for process control.
F. Modulus of Elasticity E = 10,600.000 psi.
Reference
1.
Metals Handbook, 8th Ed., Vol. 1, PP 938-940, Vol. 2, PP 271-277.
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#10 HARDENABILITY OF STEEL
(JOMINY END QUENCH TEST)
Objectives
1.
To study the effects of heat treatment on the hardness of a Jominy test sample along its axis for
different steel alloys.
2.
To quantitatively evaluate the hardenability, or depth of Hardness, of a steel rod through application
of the standard (ASTM A255) Jominy End-Quench Test.
Introduction
Carbon is soluble in Face Centered Cubic (gamma) Iron up to 2.0 percent depending on the temperature.
However, in body-centered-cubic (alpha) Iron, the maximum solubility is about 0.025 percent. Steel is
basically an alloy of Iron and Carbon containing between 0.1 and 2.0 percent Carbon. It exists therefore as a
single-phase solid solution in the temperature range in which the FCC phase is stable.
When this solid solution (austenite) is cooled below the critical temperature it becomes unstable. Most of the
Iron tends to precipitate as nearly pure Iron in the body-centered-cube form (ferrite), and most of the Carbon
tends to come out as the inter-metallic compound Fe3C (cementite). The transformation of austenite requires
redistribution of Carbon atoms from a random distribution in the solid solution to one in which nearly all of
the Carbon is contained in the Fe3C particles.
The mechanical properties of steel depend to a great extent upon the final dispersion of Carbon atoms or of
Fe3C particles in the Iron matrix. Since redistribution of Carbon atoms requires diffusion and since the rate of
diffusion decreases exponentially with decreasing temperature, the coarsest dispersions of Fe 3C (cementite)
and of ferrite result from transformation that is allowed to take place just below the critical temperature. If
the transformation is forced to take place at lower and lower temperatures by increasing the rate of cooling,
then finer and finer dispersions of the hard brittle Carbon-rich phase (cementite) and the relatively soft
ductile alpha Iron (ferrite) are produced. The Hardness of steel generally increases with the fineness of the
dispersion.
If the rate of cooling is still further increased, the precipitation of Carbon as Fe 3C can be suppressed
altogether. The face-centered cubic solid solution transforms into a distorted body-centered structure
(martensite, a body-centered tetragonal) in which the Carbon atoms are still distributed nearly at random.
This is the hardest structure for a given steel. In spite of its high strength, martensite is seldom desirable
because of low ductility. It is not an equilibrium structure, but persists at room temperature only because the
mobility of Carbon at this temperature is low.
Transformation of austenite to martensite is accompanied by a volume expansion. When a steel part is
cooled, heat must flow from the center of the part to the surface. If the rate of heat extraction is high, such as
during quenching in water, the temperature difference between surface and center can become considerable
even for moderate thickness. Thus, the surface can transform to martensite while the center is still hot
enough to plasticly deform at relatively low stress levels. When the center finally does transform it expands
further, causing tensile stresses in the surface layers. Such stresses can lead to cracking. Therefore, in the
hardening of steel it is important to avoid large differences in temperature between the surfaces and the
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center of a part during cooling. However, if a fully martensitic structure is to be produced in a plain Carbon
steel, it is necessary that all parts of the specimen to be produced in a plain Carbon steel, it is necessary that
all parts of the specimen be cooled from about 870 oC to about 320oC in about one second. This means that
only thin sections of plain Carbon steels can be fully hardened. In order to harden thick sections fully and to
avoid the danger of warping or cracking due to quenching stresses, it is necessary to have a steel in which the
transformation of austenite to ferrite and cementite is less rapid.
The Hardness of steel depends primarily on the Carbon content and the cooling rate when the material is
formed. Any alloying elements present in the steel do not affect the maximum attainable Hardness, as it is
monotonically increasing function of the amount of Carbon of up to 0.60%. On the other hand, the amount
and type of alloy do dramatically affect the hardenability of a steel. All elements, except those actually
combined as carbides of that tend to form fine grains, increase the hardenability. Thus, the addition of small
amounts of alloying elements such as chromium, molybdenum, nickel, and vanadium decreases the rate at
which austenite transforms to ferrite and cementite and therefore makes it possible to achieve a fully
hardened or martensitic structure with slower structure with slower rates of cooling. The cooling rate
depends upon the type of quench media used on its velocity. Water or Brine are severe quenching media,
whereas oil and air are much less severe. Agitated water is more severe than still water.
A steel is said to have high hardenability if it can be cooled slowly and still form the martensitic structure.
For a given rate of heat extraction, the higher the hardenability the greater the depth to which martensite
structure will form. The Jominy test is used as a quantitative measure of hardenability. A bar of steel one inch
in diameter and four inches long is heated into the austenite temperature range. It is cooled by directing a
stream of water against one end. This results in a gradient of cooling rate from one end to the other. The end
against which the water is directed receives a rapid water quench, whereas the opposite end cools very
slowly. The distance from the water-cooled end to which martensite forms can be used as a quantitative
measure of hardenability. The cooling rate at the center of a machine part to be hardened can be correlated
with the cooling rate at some position along a Jominy bar.
Equipment & Supply
1.
Jominy end-quench specimen
2.
Jominy end-quench apparatus
3.
Heat treating furnace
4.
Belt sander
5.
Rockwell Hardness Tester
6.
Tongs
7.
Bluing
8.
Scriber
9.
Polishing wheels, polish
10. Etchant, 2% Nital
11. Microscope
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Procedure
1.
Study:
a.
b.
ASTM, A255
Text reference to Jominy end-quench test
2.
Heat the furnace to recommended austenitizing temperature.
3.
Record identification and specifications of specimen.
4.
Place specimen in furnace and maintain austenitizing temperature at least 30 minutes, but not over
one hour.
5.
With a "quick valve" in full open position, use the faucet to adjust the water height to 2 1/2 inches.
After adjusting the height, turn the "quick valve" to allow about 1/16 inch trickle to flow from the
nozzle.
6.
Quench: When the specimen has been austenitized, remove the sample from the furnace and drop
it into place in the end quench fixture. Immediately turn on the water with the quick valve.
Note: While this should all take place within a 5-second time span, a
piece of steel at 1500oF is dangerous - be careful.
7.
After specimen has been end-quenched for at least 10 minutes, remove it from the fixture and finish
cooling it in water.
Note: Material is hot and should be handled with caution.
8.
Use belt sander to grind a flat surface about 1/4" wide and 1/32" deep along the entire length of the
bar in order to remove oxide scale and any decarburized material from the surface. Take care
specimen is not heated enough to temper it. EYE PROTECTION REQUIRED.
9.
Starting from the quenched end, make Hardness tests every 1/16" for the first inch, every 1/8" for
the second inch, and every 1/4" thereafter.
Note: To make Hardness readings, put the specimen in the magnetic vice.
Each full revolution of the crank is 1/16". Because of the somewhat
erratic nature of the readings, it is recommended that 2 or 3 sets
of readings be obtained.
10. Plot the average of these readings for any one point.
11. Carefully polish the flat section and etch for 15 se. in 2% nital.
specimen to air dry, do not dry with a towel.
Flush with alcohol to dry.
Allow
12. Examine the polished flat under the microscope and make sketches at selected spots in order to
correlate the Hardness with the microstructure.
Graph (required content)
1.
Make a plot of the Rc Hardness versus distance from the quenched end,
using the standard ASTM Hardenability Chart.
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Report (required content)
1.
Give a brief description of the procedure.
2.
Present the results, refer to the data, the graph, and the sketches.
3.
Discuss the results, procedure, accuracy, etc.
4.
Other:
a. Graph
b. Sketches
c. Data sheet
d. Directions and background information supplied.
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Jominy End-Quench Test Data Sheet
Student
Sample Identification
Date Tested
________________________________________
_________________
Hardness readings
Hardness scale
Weight
Indentor
Specimen Description:
Date & Time:
Rockwell Scale and Indentor:
Test Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Data Collected By:
Spacing from
Preceding
Measurement (in.)
Distance from
Quenched End (in.)
1/16
1/16
1/16
1/16
1/16
1/16
1/16
1/16
1/8
1/8
1/8
1/8
1/8
1/8
1/8
1/8
1/4
1/4
1/4
1/4
1/4
1/4
1/16
2/16
3/16
4/16
5/16
6/16
7/16
8/16
5/8
6/8
7/8
1
1-1/8
1-2/8
1-3/8
1-4/8
1-6/8
2
2-1/4
2-2/4
2-3/4
3
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Hardness (RC)
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