1 These test methods are under the jurisdiction of ASTM Committee E28 on 2 For referenced ASTM standards, visit the ASTM website, ronaldweinland.info, or. Key words: ISO , ASTM E8, tensile testing, metallic materials, international and ASTM E international standards to those who use. ASTM, "E8 Standard Test Methods of Tension Testing of Metallic Materials," Annual. Book or ASTM Standards, American Society for Testing and Materials, Vol.
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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. An American National Standard Designation: E 8 – 04 American Association State Highway and Transportation Officials Standard AASHTO No.: T68 Standard . E8 / E8Ma Standard Test Methods for Tension Testing of Metallic Materials. 30, $ Standard + Redline PDF Bundle ASTM License Agreement.
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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. The shape is usually elliptical. Strength see 7. When these materials are 8. Coefficient of Variation. Precision and Bias poor machining practice. E8 or E8M. Keywords increase. Request RR: The values are provided to 8. Report laboratories 8.
Tables tional specimen of Fig. This is the reasonable definition of the precision of tension test results can case for example. In general. Depending on which six specimens each. This shows that the ductility measurements cannot tolerate punch or scribe marks as gauge length indica. In each table. Elongation values generally decrease as the X1. The overall ranking from the least to the most Reductions of materials tested. Wire specimens that one is present. One other laboratory had consis- the repeatability within-laboratory precision as would be tently lower than average tensile strength results for all expected.
Note that the these specimens. The user is therefore advised to be very careful in selecting devices. The analysis X2. The relative error in using this device to X2. Repeatability is the ability of any operator to obtain X2. This has been the experience of a produc- X2. A GR and R study involves having multiple products. Measuring devices and procedures total variation due to repeatability and reproducibility is around should be selected carefully.
Reproducibility is the statistical process control SPC charts used to monitor tension ability of multiple operators to obtain similar measurements. The paint should be prevent overstating the thickness.
Before use of the the coating does not contribute significantly to the strength of device. These may include. Since GR and R is a significant concern. Documentation showing the verification force conditions. Guide E addresses this reduced sections.
For proper the strain hardening portion of the stress-strain curve at the gripping, it is desirable that the entire length of the serrated point of inflection. If there is no point at or near the onset of face of each wedge be in contact with the specimen.
For YPE. Significance and Use for threaded-end specimens is shown in Fig. This Both of these gripping devices should be attached to the heads information may be useful in comparisons of materials, alloy of the testing machine through properly lubricated spherical- development, quality control, and design under certain circum- seated bearings.
The distance between spherical bearings stances. The test methods used. Apparatus devices used for measuring linear dimensions shall be accurate and precise to at least one half the smallest unit to which the 5. The forces 5. Extensometers shall be used and verified to include 5. For specimens without machine. Any departure from this requirement may introduce a reduced section for example, full cross sectional area bending stresses that are not included in the usual stress specimens of wire, rod, or bar , the extensometer gage length computation force divided by cross-sectional area.
For measuring elongation at trated by calculating the bending moment and stress thus added. This error increases to 2.
Test Specimens 5. These wedge grips generally furnish a 6. If, specifications for the material being tested.
When liners are used behind the follows: For best results, the wedges should be diameter, or distance between flats. Wide 14 in. G—Gage length Note 1 and Note 2 8. Either a set of nine or more punch marks 1 in. NOTE 3—For the three sizes of specimens, the ends of the reduced section shall not differ in width by more than 0. Also, there may be a gradual decrease in width from the ends to the center, but the width at each end shall not be more than 0. In such cases the width of the reduced section should be as large as the width of the material being tested permits; however, unless stated specifically, the requirements for elongation in a product specification shall not apply when these narrower specimens are used.
NOTE 5—The dimension T is the thickness of the test specimen as provided for in the applicable material specifications. NOTE 7—The dimension shown is suggested as a minimum. In determining the minimum length, the grips must not extend in to the transition section between Dimensions A and B, see Note 9.
NOTE 9—It is desirable, if possible, to make the length of the grip section large enough to allow the specimen to extend into the grips a distance equal to two thirds or more of the length of the grips. NOTE 10—For the three sizes of specimens, the ends of the specimen shall be symmetrical in width with the center line of the reduced section within 0. NOTE 11—For each specimen type, the radii of all fillets shall be equal to each other within a tolerance of 0.
NOTE 12—Specimens with sides parallel throughout their length are permitted, except for referee testing, provided: If the fracture occurs at a distance of less than 2W from the edge of the gripping device, the tensile properties determined may not be representative of the material.
In acceptance testing, if the properties meet the minimum requirements specified, no further testing is required, but if they are less than the minimum requirements, discard the test and retest. It is important, therefore, that care be exercised in measured.
For this reason, a small taper is permitted in the reduced section of each of the specimens 6. When product specifications so permit, other types of specimens may be used, as provided in 6. In order to avoid buckling in tests of thin and high-strength materials, it may be neccessary to use stiffening plates at the grip ends. These may be used when it is necessary applicable product specifications.
Other sizes of small round quality of surface finish of specimens for high strength and very low specimens may be used. In any such small-size specimen it is ductility materials since this has been shown to be a factor in the important that the gage length for measurement of elongation variability of test results. When product may be applied axially.
This specimen is used for testing metallic materials in the described in the following: Dimensions in. G—Gage length 2. There may be a gradual taper in width from the ends to the center, but the width at each end shall be not more than 0. NOTE 2—The dimension T is the thickness of the test specimen as stated in the applicable product specifications.
NOTE 4—Holes must be on center line of reduced section, within Nominal Diameter 0. NOTE 2—If desired, the length of the reduced section may be increased to accommodate an extensometer of any convenient gage length.
Reference marks for the measurement of elongation should, nevertheless, be spaced at the indicated gage length. NOTE 3—The gage length and fillets may be as shown, but the ends may be of any form to fit the holders of the testing machine in such a way that the load shall be axial see Fig.
If the ends are to be held in wedge grips it is desirable, if possible, to make the length of the grip section great enough to allow the specimen to extend into the grips a distance equal to two thirds or more of the length of the grips. In some product specifications other specimens may be provided for, but unless the 4-to-1 ratio is maintained within dimensional tolerances, the elongation values may not be comparable with those obtained from the standard test specimen.
NOTE 5—The use of specimens smaller than 0. Smaller specimens require suitable equipment and greater skill in both machining and testing. NOTE 6—Five sizes of specimens often used have diameters of approximately 0. Thus, when the actual diameters agree with these values, the stresses or strengths may be computed using the simple multiplying factors 5, 10, 20, 50, and , respectively. The metric equivalents of these five diameters do not result in correspondingly convenient cross-sectional areas and multiplying factors.
Round Tension Test Specimen with 2-in. In testing wire, rod, or bar 0. For material not exceeding 0. The thickness of this modified specimen must distance between flats, the cross-sectional area may be reduced be machined to 0. In the event of shape of the cross section. For material over 0. Square, 6. NOTE 2—On Specimens 1 and 2, any standard thread is permissible that provides for proper alignment and aids in assuring that the specimen will break within the reduced section.
NOTE 3—On Specimen 5 it is desirable, if possible, to make the length of the grip section great enough to allow the specimen to extend into the grips a distance equal to two thirds or more of the length of the grips.
Square, hexagonal, or octagonal rod over 0. Unless otherwise specified in smaller than 0. NOTE 10—The ends of copper or copper alloy specimens may be 6. In flattening 6. The reduced width shall be not less than the original bar thickness. Also, one of the types of specimens described in 6. Test Specimens 6.
Snug-fitting metal plugs shall be inserted far enough into the ends of such tubular specimens to permit the testing machine jaws to grip the specimens properly. The plugs shall not extend into that part of the specimen on which the elongation is measured. Elongation is measured over a length of 4D unless otherwise stated in the product specification. Specimens from welded tube shall be form and dimensions shown for Specimen 2 in Fig. Specimens wall thickness, the standard specimen shown in Fig.
Specimens for transverse a surface contour corresponding to the curvature of the tube. If the tube-wall the welds at about the middle of their lengths. If round NOTE 12—In clamping of specimens from pipe and tube as may be specimens are not feasible, then the largest specimen described done during machining or in flattening specimen ends for gripping , care in 6.
Flattening of the specimen may be either after separating as separately forged coupons representative of the forging. When in A, or before separating as in B. Transverse tension test not otherwise specified, the axis of the specimen shall be parallel to the direction of grain flow. When making NOTE 1—The diameter of the plug shall have a slight taper from the line test specimens in accordance with Fig.
NOTE 2—It is desirable, if possible, to make the length of the grip section great enough to allow the specimen to extend into the grips a distance equal to two thirds or more of the length of the grips. NOTE 3—The ends of the specimen shall be symmetrical with the center line of the reduced section within 0.
NOTE 4—For each specimen type, the radii of all fillets shall be equal to each other within a tolerance of 0. In this case, the exact equation see section 7. NOTE 7—Specimens with sides parallel throughout their length are permitted, except for referee testing, provided: If the properties meet the minimum requirements specified, no further testing is required, but if they are less than the minimum requirements, discard the test and retest.
Measure and record the Cut from Tubular Products cross-sectional dimensions of tension test specimens 0. See Appendix X2 for additional information. Gage marks shall be stamped lightly with in. For material that is sensitive to the effect of slight D—Diameter 0. Energy Institute EIA: Elevator World Inc.
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