Hola

Designation: E 8 – 00

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 year of last revision. A number inparentheses 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 methods of determination of yieldstrength, 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 than combining standards asrecommended 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 test methods may need to be madein 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.

E 4 Practices for Force Verification of Testing Machines5 E 6 Terminology Relating to Methods of Mechanical Testing5 E 8M Test Methods for Tension Testing ofMetallic Materials [Metric]5 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications6 E 83 Practice for Verification and Classification of Extensometers5 E 345 Test Methods of Tension Testing of Metallic Foil5 E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method6 E 1012 Practice for Verification of SpecimenAlignment Under Tensile Loading5 3. Terminology 3.1 Definitions—The definitions of terms relating to tension 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—a hesitation or fluctuation of force observed at the onset of plastic deformation, due tolocalized yielding. (The stress-strain curve need not appear to be discontinuous.) 3.1.2 lower yield strength, LYS [FL−2]—the minimum stress recorded during discontinuous yielding, ignoring transient effects. 3.1.3 upper yield strength, UYS [FL−2]— the first stress maximum (stress at first zero slope) associated with discontinuous yielding. 3.1.4 yield point elongation, YPE—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 transition occurs over a range of strain, the YPE end point is the intersection between (a) a horizontal line drawn tangent to the curve at the last zero slope and ( b) a line drawn tangent to the strain hardening portion of the stress-straincurve at the point of inflection. If there is no point at or near the onset of yielding at which the slope reaches zero, the material has 0 % YPE.
5 6

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 practices and determine the applicability...