An American National Standard American Association State Highway and Transportation Officials Standard AASHTO No.: T68
Standard Test Methods for
Tension Testing of Metallic Materials1
This standard is issued under the ﬁxed designation E 8; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the yearof last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense.
1. Scope* 1.1 These test methods cover the tension testing of metallic materials in any form at room temperature, speciﬁcally, the methodsof determination of yield strength, yield point elongation, tensile strength, elongation, and reduction of area.
NOTE 1—A complete metric companion to Test Methods E 8 has been developed, therefore, no metric equivalents are shown in these test methods. Committee E28 was granted an exception in 1997 by the Committee on Standards to maintain E8 and E8M as separate companion standards rather thancombining standards as recommended by the Form and Style Manual. NOTE 2—Gage lengths in these test methods are required to be 4D for most round 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. NOTE 3—Exceptions to the provisions of these testmethods may need to be made in individual speciﬁcations or test methods for a particular material. For examples, see Test Methods and Deﬁnitions A 370 and Test Methods B 557. NOTE 4—Room temperature shall be considered to be 50 to 100°F unless otherwise speciﬁed.
A 370 Test Methods and Deﬁnitions for Mechanical Testing of Steel Products B 557 Test Methods of Tension Testing Wrought and CastAluminum- and Magnesium-Alloy Products E 4 Practices for Force Veriﬁcation of Testing Machines E 6 Terminology Relating to Methods of Mechanical Testing E 8M Test Methods for Tension Testing of Metallic Materials [Metric] E 29 Practice for Using Signiﬁcant Digits in Test Data to Determine Conformance with Speciﬁcations E 83 Practice for Veriﬁcation and Classiﬁcation of Extensometers E 208 TestMethod for Conducting Drop-Weight Test to Determine Nil-Ductility Transition Temperature of Ferritic Steels E 345 Test Methods of Tension Testing of Metallic Foil E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method E 1012 Practice for Veriﬁcation of Specimen Alignment Under Tensile Loading 3. Terminology 3.1 Deﬁnitions—The deﬁnitions of terms relating totension testing appearing in Terminology E 6 shall be considered as applying to the terms used in these test methods of tension testing. Additional terms being deﬁned are as follows: 3.1.1 discontinuous yielding—in a uniaxial test, a hesitation or ﬂuctuation of force observed at the onset of plastic deformation, due to localized yielding. (The stress-strain curve need not appear to bediscontinuous.) 3.1.2 lower yield strength, LYS [FL−2]—in a uniaxial test, the minimum stress recorded during discontinuous yielding, ignoring transient effects. 3.1.3 upper yield strength, UYS [FL−2]— in a uniaxial test, the ﬁrst stress maximum (stress at ﬁrst zero slope) associated with discontinuous yielding at or near the onset of plastic deformation. 3.1.4 yield point elongation, YPE— in a uniaxial test,the strain (expressed in percent) separating the stress-strain curve’s ﬁrst point of zero slope from the point of transition from discontinuous yielding to uniform strain hardening. If the
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health...