Determination of the Tensile Strength of Steel
From the video you watch about ASTM A370/ASTM E8, write a laboratory report.
It should include:
a.) Significance and use of the procedure.
4.1 The primary use of these test methods is testing to determine the specified mechanical
properties of steel, stainless steel, and related alloy products for the evaluation of
conformance of such products to a material specification under the jurisdiction of ASTM
Committee A01 and its subcommittees as designated by a purchaser in a purchase order
or contract.
4.1.1 These test methods may be and are used by other ASTM Committees and other
standards writing bodies for the purpose of conformance testing.
4.1.2 The material condition at the time of testing, sampling frequency, specimen location
and orientation, reporting requirements, and other test parameters are contained in the
pertinent material specification or in a general requirement specification for the particular
product form.
4.1.3 Some material specifications require the use of additional test methods not described
herein; in such cases, the required test method is described in that material specification or
by reference to another appropriate test method standard.
4.2 These test methods are also suitable to be used for testing of steel, stainless steel and
related alloy materials for other purposes, such as incoming material acceptance testing by
the purchaser or evaluation of components after service exposure.
4.2.1 As with any mechanical testing, deviations from either specification limits or expected
as-manufactured properties can occur for valid reasons besides deficiency of the original
as-fabricated product. These reasons include, but are not limited to: subsequent service
degradation from environmental exposure (for example, temperature, corrosion); static or
cyclic service stress effects, mechanically-induced damage, material inhomogeneity,
anisotropic structure, natural aging of select alloys, further processing not included in the
specification, sampling limitations, and measuring equipment calibration uncertainty. There
is statistical variation in all aspects of mechanical testing and variations in test results from
prior tests are expected. An understanding of possible reasons for deviation from specified
or expected test values should be applied in interpretation of test results
b.) Apparatus needed
ASTM E8 / E8M allows for many different specimen types and defines suitable
geometries and dimensions for each one. Bars, tubes, sheets, pin-loaded specimens,
round specimens, and powdered metallurgy products are some of the many options for
testing to this standard. However, the most common specimen is a dogbone-shaped
rectangle with a width of 12.5 mm (0.5 in) and gauge length of 50 mm (2 in).
c.) Methodology
Note that in general, the testing equipment and methods are given in ASTM E8.
However, there are certain exceptions to ASTM E8 practices in the testing of steel, and
these are covered in the methods below.
Procedure A: Tension Test
Measure and record the specimen dimensions necessary to determine the cross
sectional area at its smallest point. The original cross sectional area is used for all
engineering stress calculations.
Mark the gauge length with a center punch, scribe marks or draw with ink. The distance
between the gauge marks after the specimen is broken is used to determine the percent
elongation at break.
Zero the testing machine without the specimen inserted in the grips. Install the specimen in
the grips and attach a Class B1 axial extensometer to the specimen. Please note that the
extensometer needs to be removed prior to specimen failure. ADMET software stops test
and prompts the removal of the extensometer once the total strain data has been
satisfactorily obtained.
Start loading the sample. The speed of testing is generally specified in one of three
manners: a) rate of movement of the crosshead of the testing machine when not under
load; b) the rate of stressing of the specimen; or c) the rate of separation of the crossheads
under load. Any convenient speed of testing may be used up to one half the specified yield
point and down to 1/10 the specified maximum rates for determining yield strength and
tensile strength.
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 0.05 millimeters.
Calculations:
Ultimate Tensile Strength or Peak Stress
Yield Strength by Offset or Extension Under Load Method
Percent Elongation at Break (includes plastic deformations only)
Reduction of Area
Yield Point Elongation (YPE)
Elongation at Fracture (includes elastic and plastic deformations)
Procedure B: Bend Test
Test methods E190 and E290 should be consulted to perform bend testing per ASTM
A370. Bend tests should be performed to test ductility but it cannot be considered as a
quantitative means of predicting service performance in bending operations.
Calculations:
Bend Strength
d.) Analysis and
ASTM A370 is a testing standard that covers the mechanical testing definitions and
procedures of steel products such as wrought and cast steels, stainless steels, and related
alloys. This standard covers tension, bend, hardness, and impact tests.
g.) Recommendation and Conclusion
The various mechanical tests described in this specification can be used to determine
the properties required in the product specifications. ADMET universal testing machines
conform to the requirements of Practices E4 and can be used for A370 tension and bend
testing. Hardness and impact tests will not be covered in detail in this post, as we do not
offer machines for these tests. Prior to conducting ASTM A370, it is important to read the
entire specification in the relevant ASTM publication.
h.) EVALUATION QUESTIONS: Answer this questions in your own opinion and
understanding
1. Why do we need to determine the tensile strength of the steel?
The reason why we need to determined the tensile strength of the steel is that to find the
safest material that can be used in building construction. Despite of this, you can also be
assured that your used materials can handle the different situations such as
hazardousness and suddenly faultiness.
