This standard is issued under the fixed designation E8/E8M; the number 1 These test methods are under the jurisdiction of ASTM Committee E28 on. E8 / E8Ma Standard Test Methods for Tension Testing of Metallic Materials. ADD TO CART. 30, $ Standard + Redline PDF Bundle. E8/E8M - 13 Standard Test Methods for Tension Testing of Metallic Materials, accuracy, bending stress, discontinuous PDF, 28, $, ADD TO CART.
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For Test Specimens with Gauge Length Four times the Diameter (E8]. Standard. Small-Size Specimens Proportional to Standard. Specimen. Specimen 1. An American National Standard Designation: E 8 – 04 American Association State Highway and Transportation Officials Standard AASHTO No.: T68 Standard . ASTM E8/E8M: Standard Test Methods for Tension Testing of Metallic PDF + Print for most round specimens are required to be 4D for E8 and 5D for E8M.
Gauge marks shall be stamped lightly min with a punch. In such cases.
Artificial methods of removing the preload on dimensions B and C given above. NOTE 13—Preloads generated by gripping of specimens may be either tensile or compressive in nature and may be the result of such things as: R—Radius of fillet. D—Diameter Any force or preload imparted by the gripping of NOTE 1—The reduced parallel section dimensions A and D and the specimen see Note 13 must be indicated by the force shoulders dimensions E.
Commonly the ends are threaded and have the prior to testing. For material that is sensitive to the effect of slight B—Length of end 25  25  45 [1. C—Diameter of end 20 [0. In general-purpose tensile testing.
The elapsed time can be determined with ment and control of the rate of stressing. Leg Design. If a bend bar is required. Use of and size is at the option of the foundry. Radius at bottom 13 mm [0. In such instances.
Width at top 32 mm [1. T riser taper foundry for the following reasons: Many testing machines are equipped with and the use for which the test results are intended. Location of test bars The tensile. End taper 2. Many testing machines are force. Width the foundry. The length of foundry to accommodate additional test bars see the riser at the top therefore depends on the Note 1. Use of and size of end taper is at the option of — 0. Rx Radius from 0 to approximately 2 mm [0.
L length The length of the riser at the base will be the This length may be increased at the option of the same as the top length of the leg. Number of legs the option of the foundry providing they are Height are cast open. Spacing between legs A 13 mm [0. The maximum height is at the option of the The number of legs attached to the coupon is at 3. In cases where different length committees. The width of the riser at the base of a multiple-leg coupon shall be n 57 mm — 16 mm [n 2.
Height 32 mm [1. Suitable limits for speed of testing should be specimens may be used. The test coupons in Fig. The minimum height of the riser shall be 51 mm [2 in. NOTE 18—For machines not having crossheads or having stationary but in the absence of such a device the average rate of straining crossheads. The width of the riser at the top is therefore dependent on the amount of taper added to the riser.
L length A mm [5-in. In the absence of any using suitable length-measuring and timing devices. If different speed limitations are tion in the linear elastic region is between 1. NOTE 20—In the previous and following paragraphs. The limits for product properties against a specification value should be run the crosshead speed may be further qualified by specifying using the same control method and rate used to determine the different limits for various types and sizes of specimens.
The speed above this point shall machine shall be operated such that the rate of stress applica- be within the specified limits.
In all cases. The speed of the testing machine In this method. Appendix X4 provides additional guidance on NOTE 19—For machines not having crossheads or having stationary crossheads.
The specification value unless it can be shown that another method average crosshead speed can be experimentally determined by yields equivalent or conservative results. Polish with 00 emery cloth section 4. Methods proper safety limits are not set. While both of these methods will provide similar rates of stressing and straining prior to the onset of yielding. Rough machine reduced parallel section to 6.
In practice. The ends as shown are designed to provide a practical minimum pressing area. When a specimen being split collet and supported under the shoulders. As an example. R—Radius of gauge fillet 6. Rate of Straining Control in Fig.
Other end designs are acceptable. Lap with crocus cloth B—Grip length It is not recommended that the F—Diameter of shoulder 7. Finish turn 4. The radius of the collet tested begins to yield. The rate of straining shall be set and NOTE 25—It is recommended that crosshead speed be used for control maintained at 0. To machine in closed-loop strain control because unexpected crosshead achieve the best reproducibility in cases where the material may be movement may occur if the control parameters are not set properly.
To specimen. NOTE 26—Using different Control Methods may produce different yield NOTE 23—Proper precautions must be observed when operating a results especially if the material being tested is strain-rate sensitive. For steels with nominal yield strengths of less than MPa [80 psi]. Determine the upper or lower yield strength as follows: For higher strength steels. Extensometers and other devices used in determination of NOTE 31—Yield properties of materials exhibiting yield point elonga.
Strain 7. If Class C curve. When determining only the tensile strength. Report the stress at the specified extension as follows: In reporting values of yield strength ob- should be avoided for strain rate sensitive materials if it is desirable to tained by this method.
The control method described in 7. For these cases. Offset and extension-under-load EUL yield strengths may be significantly affected by stress fluctuations occur- low-magnification Class C devices is helpful. For most machined specimens. Appendix X5 shows examples of test at the speed used to determine yield properties. See Fig. Determination of upper or lower yield strengths or both may devices are used. The stress corresponding to the load at the instant of detectable elongation may be recorded as the approximate extension-under-load yield strength.
NOTE 34—In practice.
This is illustrated in Fig. When the force hesitates. Use a class C or better FIG. NOTE 37—The stress-strain curve of a material exhibiting only a hint of the behavior causing YPE may have an inflection at the onset of yielding Stress with no point where the slope reaches zero Fig.
Class C extensometers may be Stress employed. When this is done but the material exhibits no discontinuous yielding. For such materials. But No YPE Materials exhibiting inflections. Such a material has no YPE. To accommodate this. NOTE 38—When uniform elongation is being determined digitally. Results from the elongation-at- Maximum fracture method are generally more repeatable. Measure the final gauge length to the nearest selected arbitrarily. A percentage scale reading — Determine the maximum force recorded after discontinuous yield.
See Appendix X1 for additional information on the effects of these variables. Elongation at fracture and elongation after fracture are not interchangeable parameters.
Where this may occur. Values ranging from 0. Force Detail of plateau region force scale magnified 7. When disagreements arise over the elongation results. Parties involved in force comparison or conformance testing should standardize the above items.
Fmax requirements of 7. The use of ancillary devices. Elongation fit ends of the fractured specimen together carefully and FIG. The procedure given in 7. Elu 7. Force Fig. NOTE 39—If the upper yield strength is the maximum stress recorded. Fit the fractured ends together with peak force value. Either value may be reported. Pay particular attention to requirements for low-elongation materials. In actual practice. If any part of the fracture occurs outside specified procedure.
Sections—Fit the ends of the fractured specimen together and 7. When this assumption is made. In the absence of a specified procedure 7. The shapes of these ment points. NOTE 45—Because of the constraint to deformation that occurs at the correction for elastic strains requires knowledge of the variable strain corners of rectangular specimens.
In the absence of a defined gauge length. NOTE 43—Unless the specimen has not necked at the point of fracture. An effective width may be similarly calculated. NOTE 46—For steel products. If such an elongation measure is obtained in acceptance testing involving 7.
Current edition approved Aug. Published September Originally approved in DOI: Such interpretation is usually applicable to values for reduction of area reported in the literature when no further qualification is given. Significance and Use 4. This information may be useful in comparisons of materials, alloy development, quality control, and design under certain circumstances.
The test methods have been used extensively in the trade for this purpose. Apparatus 5. The forces used in determining tensile strength and yield strength shall be within the verified force application range of the testing machine as defined in Practices E4. Where verification of the testing machine speed is required, Practices E shall be used unless otherwise specified. To ensure axial tensile stress within the gauge length, the axis of the test specimen should coincide with the center line of the heads of the testing machine.
Any departure from this requirement may introduce bending stresses that are not included in the usual stress computation force divided by cross-sectional area.
For a standard This error increases to 2. For measuring elongation at fracture with an appropriate extensometer, the gauge length of the extensometer shall be equal to the nominal gauge length required for the specimen being tested. These wedge grips generally furnish a satisfactory means of gripping long specimens of ductile metal and flat plate test specimens such as those shown in Fig.
If, however, for any reason, one grip of a pair advances farther than the other as the grips tighten, an undesirable bending stress may be introduced. When liners are used behind the wedges, they must be of the same thickness and their faces must be flat and parallel. For best results, the wedges should be supported over their entire lengths by the heads of the testing machine. This requires that liners of several thicknesses be available to cover the range of specimen thickness.
For proper gripping, it is desirable that the entire length of the serrated face of each wedge be in contact with the specimen. Proper alignment of wedge grips and liners is illustrated in Fig. For short specimens and for specimens of many materials it is generally necessary to use machined test specimens and to use a special means of gripping to ensure that the specimens, when under load, shall be as nearly as possible in uniformly distributed pure axial tension see 5.
Both of these gripping devices should be attached to the heads of the testing machine through properly lubricated sphericalseated bearings. The distance between spherical bearings should be as great as feasible. It is important, therefore, that care be exercised in the preparation of specimens, particularly in the machining, to maximize precision and minimize bias in test results.
Test Specimens NOTE 3—Punching or blanking of the reduced section may produce significant cold work or shear burrs, or both, along the edges which should be removed by machining. For this reason, a small taper is permitted in the reduced parallel section of each of the specimens described in the following sections.
Extensometers shall be used and verified to include the strains corresponding to the yield strength and elongation at fracture if determined. T H Hill Associates, Inc. Technical Indexes, Ltd. Telecommunications Industry Association TP: Technology Perspectives TPI: Trans Tech Publications Inc. Tyrell Press, Ltd. International Union of Railways UL: UL ULC: United Nations UNI: The U.
Verband der Automobilindustrie VDE: Welding Consultants, Inc. World Scientific Publishing Co. Yakuji Nippo. Complete Document.
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Some rush fees may apply. Add to Cart. People Also Bought These: Related Products: 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. The gauge length is the most significant difference between E8 and E8M test specimens. Exceptions to the provisions of these test methods may need to be made in individual specifications or test methods for a particular material.
The values stated in each system are not exact equivalents; therefore each system must be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
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 of regulatory limitations prior to use.
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