Standard Test
Methods for
Tension Testing
of Metallic
Materials
SCOPE
1. These test methods cover the tension testing
of metallic materials in any form at room
temperature. (10-38 C or 50 to 100 F)
determine
yield strength
yield point elongation
tensile strength
elongation
reduction of area
2. The gauge lengths for most round specimens
are required to be 4D for E8 and 5D for
E8M
3. The values stated in metric units are to be
regarded as separate from meter/gram unit.
Significance and Use
Tension test provide information on strength and
ductility of materials under tensile stresses. This
information may be useful in comparisons of
materials, alloy development, quality control, and
design under certain circumstances.
Testing Machine
Apparatus
Gripping Device
Dimension-Measur Devices
Extensometer
Testing Machine
Universal Testing Machine
is capable of applying tensile
load at a controlled rate of
deformation or load
Gripping Device
A gripping device, used to transmit
the load from the testing machine
to the test.
Dimension-Measure Devices
vernier caliper & Micrometer
Used to measure th edimensions of the
sppecmen
Extensometer
Extensometer used to measure
the deformation of the
specimens
TEST SPECIMENS
When preparing the specimen, that should
be free of cold work, notches, chatter
marks, grooves, gouges, burrs, rough
surface or edges, overheating or other
condition which can deleteriously affect
the properties to be measured
Specimens Dimension
FIG. 1 Rectangular Tension Test Specimens Sheet and Plate types
Procedure
1.Measure and record thee specimen dimension necessary to determine
the cross-sectional area at the smallest point. the original cross sectional area is used for all engineer.
2 . Use ink and a scribe or punch to place gauge marks on the test
specimen at the appropriate gauge length. The distance between the gauge
mark after the specimen is broken is used to determine the percent
elongation at break.
(To accurately compare elongation value between tests ,the gauge length
must be same)
3. Zero the testing machine without the specimen inserted in the grips. The install the
specimen in the specimen in the grips and start loading the sample. The speed of
testing is generally specified in one of three manner
a) the rate of straining of the specimen is 0.015±o.006 mm/mm/min
(0.5 in/in of the gauge length per minute )
b) the rate of stressing of the specimen is 1.15-11.5 MaP
c) the rate of separation of the crossheads is 0.015±0.003 mm/mm/min
In addition, the test rate is to remain constant through yield ultimate tensile
strength and elongation at break.
4. Run the test until specimen failure or fracture. Remove the broken sample from
the machine and fit the fractured ends together.
(Measure the distance between the gauge marks to the nearest o.05 millimeter)
Analysis and Results
Plot the stress versus strain curve.
Determining the yield strength using offset method
Determining the modulus of elasticity using Hooke's law
σ=E
where:
E =Modulus of elasticity
σ =stress in proportional limit
ε= corresponding strain, mm/mm(in./in.)
FIG. 2 Stress-Straincurve
Calculate the tensile strength
σ max = P max /Ao
FIG. 3 Stress-Strain curve for Determination of Yield
Strength
where:
σ max =tensile strength/ ultimate strength ,in MPa(psi)
P max=maximum load carried by the specimen during tension test, N(Ib)
Ao= original cross- sectional area of the specimen, mm^2(in)^2
Calculate the elongation
FIG. 4 Stress-Strain Diagram Showing Yield Point Elongation.
Percent elongation = [(Ls-Lo)/Lo) x 100]
where:
Ls = gauge length after rupture, mm(in.)
Lo = original gauge length, mm(in.)
For elongation > 3.0 percent, fit the ends of the fractured
specimen together and measure Ls as the distance between two
gauge marks. For elongation < or equal 3.0 percent, fit the
fractured ends together and apply an end load along the axis of
the specimen sufficient to close the fractured ends together, then
measure Ls as the distance between gauge marks.
Calculate the reduction of
cross-sectional area
percent reduction in cross-sectional area =[ (Ao-As)/Ao ) x 100 ]
where:
Ao = original cross - sectional area of the specimen, mm^2(in.)^2
As = cross- sectional area after rupture, mm^2(in.)^2
Report
1 Test information on materials not covered by a product specification should be reported in
accordance with 8.2 or both 8.2 and 8.3.
2 Test information to be reported shall include the follow- ing when applicable:
Reference to the standard used, i.e. E8 or E8M. 8.2.2 Material and sample identification
3 Specimen type.
Yield strength and the method used to determine yield.
Yield point elongation .
Tensile Strength (also known as Ultimate Tensile Strength) .
Elongation (report original gauge length, percentage
increase, and method used to determine elongation; i.e. at fracture or after fracture)
3 Test information to be available on request shall include. Specimen test section dimension(s).
Equation used to calculate cross-sectional area of
rectangular specimens taken from large-diameter tubular prod- ucts.
Speed and method used to determine speed of testing .
Method used for rounding of test results.
Reasons for replacement specimens
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MEMBER
Mr.Napat Potisan
ID 6331112002
Mr.Arthiwat Yatyuklai ID 6331112019
Mr.Si Thu Wai