ASTM E8/E8M-21 pdf free download.Standard Test Methods for Tension Testing of Metallic Materials.
1 .1 These test methods cover the tension testing of metallic materials in any form at room temperature, specifically, the methods of determination of yield strength. yield point elongation, tensile strength. elongation, and reduction of area.
1.2 The gauge lengths for most round specimens are required to be 4D for E8 and 5D for E8M. The gauge length is the most significant difference between E8 and E8M test specimens. Test specimens made from powder metallurgy (P/M) materials are exempt from this requirement by industry- wide agreement to keep the pressing of the material to a specific projected area and density.
1.3 Exceptions to the provisions of these test methods may need to be made in individual specifications or test methods for a particular material. For examples, see Test Methods and Definitions A370 and Test Methods B557, and B557M.
1.4 Room temperature shall he considered to he 10 to 38°C (50 to 100°F] unless otherwise specified.
1 .5 The values stated in SI units are to he regarded as separate from inch/pound units. The values stated in each system are not exact equivalents; therefore each system must he used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1 .6 This standard does not purport to address all of the saferv concerns, if an associated with its use. It is the responsibility of (lie user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardiza -tion established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. 1.1 The definitions of mechanical testing terms that appear in the Terminology E6 apply to this test method.
3. 1.1.1 These terms include bending strain, constraint, elongation, extensometer, force, gauge length, necking. reduced section. stress-strain diagram. testing machine, and modulus of elasticity.
3.1.2 In addition, the following common terms from Terminology E6 are defined:
3. 1 .3 discontinuous yielding, n—in a uniaxial test, a hesitation or fluctuation of force observed at the onset of plastic deformation, due to localized yielding.
3.1.3.1 Discussion—The stress-strain curve need not appear to be discontinuous.
3. 1 .4 elongation after fracture, n—the elongation measured by fitting the two halves of the broken specimen together.
3.1.5 elongation at fracture, n—the elongation measured just prior to the sudden decrease in force associated with fracture.ASTM E8/E8M pdf download.