1、Designation: B557M 14B557M 15Standard Test Methods forTension Testing Wrought and Cast Aluminum- andMagnesium-Alloy Products (Metric)1This standard is issued under the fixed designation B557M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 These tes
3、t methods cover the tension testing of wrought and cast aluminum- and magnesium-alloy products, exceptingaluminum foilwith the exception of aluminum foil,2, and are derived from Test Methods E8M, which cover the tension testing ofall metallic materials.NOTE 1These metric test methods are the equival
4、ents of those in Test Methods B557, and are compatible in technical content except for therequirement of longer gage lengths for round specimens.NOTE 2Foil is sheet metal less than 0.20 mm thick. There is an overlap in the thickness range 0.15 to 0.20 mm defined for foil and sheet. Sheetproducts in
5、this thickness range are supplied to sheet product specifications and foil products in this thickness range are supplied to foil productspecifications. Exceptions to the provisions of these test methods may need to be made in individual specifications or test methods for a particular material.1.2 Th
6、e values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropr
7、iate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3B209 Specification for Aluminum and Aluminum-Alloy Sheet and PlateE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Method
8、s of Mechanical TestingE8M Test Methods for Tension Testing of Metallic Materials Metric (Withdrawn 2008)4E29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE83 Practice for Verification and Classification of Extensometer SystemsE345 Test Methods of Te
9、nsion Testing of Metallic FoilE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE1012 Practice for Verification of Testing Frame and Specimen Alignment Under Tensile and Compressive Axial ForceApplication3. Terminology3.1 The definitions of terms relati
10、ng to tension testing appearing in Terminology E6 shall be considered as applying to the termsused in these test methods.4. Significance and Use4.1 Tension tests provide information on the strength and ductility of materials under uniaxial tensile stresses. This informationmay be useful in compariso
11、ns of materials, alloy development, quality control, and design under certain circumstances.1 These test methods are under the jurisdiction ofASTM Committee B07 on Light Metals andAlloys and are the direct responsibility of Subcommittee B07.05 on Testing.Current edition approved May 15, 2014Oct. 1,
12、2015. Published July 2014October 2015. Originally approved in 1976. Last previous edition approved in 20102014 asB557M 10.B557M 14. DOI: 10.1520/B0557M-14. 10.1520/B0557M-15.2 For test methods of tension testing of aluminum foil, see Test Methods E345.3 For referencedASTM standards, visit theASTM we
13、bsite, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4 The last approved version of this historical standard is referenced on www.astm.org.This document is not an
14、 ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. I
15、n all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 Th
16、e results of tension tests of specimens machined to standardized dimensions from selected portions of a part or materialmay not totally represent the strength and ductility properties of the entire end product or its in-service behavior in differentenvironments.4.3 These test methods are considered
17、satisfactory for acceptance testing of commercial shipments and have been usedextensively in the trade for this purpose.5. Apparatus5.1 Testing MachinesMachines used for tension testing shall conform to the requirements of Practices E4. The forces usedin determining tensile strength and yield streng
18、th shall be within the verified force application range of the testing machine asdefined in Practices E4.5.2 Gripping Devices:5.2.1 GeneralVarious types of gripping devices may be used to transmit the measured load applied by the testing machineto the test specimens. To ensure axial tensile stress w
19、ithin the gage length, the axis of the test specimen must coincide with thecenterline of the heads of the testing machine. Any departure from this requirement may introduce bending stresses that are notincluded in the usual stress computation (load divided by cross-sectional area).NOTE 3The effect o
20、f this eccentric loading may be illustrated by calculating the bending moment and stress thus added. For a standard 12.50-mmdiameter specimen, the stress increase is 1.5 percentage points for each 0.025 mm of eccentricity. This error increases to about 2.3 percentage points/0.025mm for a 9-mm diamet
21、er specimen and to 3.25 percentage points /0.025-mm for a 6-mm diameter specimen.NOTE 4Alignment methods are given in Practice E1012.5.2.2 Wedge GripsTesting machines usually are equipped with wedge grips. These wedge grips generally furnish asatisfactory means of gripping long bars of ductile metal
22、. If, however, for any reason, one grip of a pair advances farther than theother as the grips tighten, an undesirable bending stress may be introduced. When liners are used behind the wedges, they mustbe of the same thickness and their faces must be flat and parallel. For best results, the wedges sh
23、ould be supported over their entirelength by the heads of the testing machine. This requires that liners of several thicknesses be available to cover the range ofspecimen thickness. For proper gripping, it is desirable that the entire length of the serrated face of each wedge be in contact withthe s
24、pecimen. Proper alignment of wedge grips and liners is illustrated in Fig. 1. For short specimens it is generally necessary touse machined test specimens and to use a special means of gripping to ensure that the specimens, when under load, shall be asnearly as possible in uniformly distributed pure
25、axial tension (see 5.2.35.2.3 5.2.5, 5.2.4, and 5.2.5).5.2.3 Grips for Threaded and Shouldered SpecimensA schematic diagram of a gripping device for threaded-end specimensis shown in Fig. 2, while Fig. 3 shows a device for gripping specimens with shouldered ends. Both of these gripping devices shoul
26、dbe attached to the heads of the testing machine through properly lubricated spherical-seated bearings. The distance betweenspherical bearings should be as large as feasible.5.2.4 Grips for Sheet MaterialsThe self-adjusting grips shown in Fig. 4 have proved satisfactory for testing sheet materialsth
27、at cannot be tested satisfactorily in the usual type of wedge grips.5.2.5 Grips for WireGrips of either the wedge or snubbing types as shown in Fig. 4Figs. 4 and 5 and Fig. 5or flat wedge gripsmay be used.5.3 Dimension-Measuring DevicesMicrometers and other devices used for measuring linear dimensio
28、ns shall be accurate andprecise to at least one half the smallest unit to which the individual dimension is required to be measured.5.4 ExtensometersExtensometers used in tensile testing shall conform to the requirements of Practice E83 for theclassifications specified by the procedure section of th
29、ese test methods. Extensometers shall be used and verified to include thestrains corresponding to the yield strength and elongation at fracture (if determined).5.4.1 Extensometers with gage lengths equal to or shorter than the nominal gage length of the specimen (dimension shown as“G-gage Length” in
30、 the accompanying figures) may be used to determine the yield behavior. For measuring elongation at fracturewith an appropriate extensometer, the gage length of the extensometer shall be equal to the nominal gage length required for thespecimen being tested.FIG. 1 Wedge Grips with Liners for Flat Sp
31、ecimensB557M 152FIG. 2 Gripping Device for Threaded-End SpecimensFIG. 3 Gripping Device for Shouldered-End SpecimensB557M 1536. Test Specimen6.1 General:6.1.1 Test specimens shall be of the full section of the material whenever practical. Otherwise, machined specimens ofrectangular or round cross se
32、ction shall be used.6.1.2 Improperly prepared test specimens often are the reason for unsatisfactory and incorrect test results. It is important,therefore, that care be exercised in the preparation of specimens, particularly in the machining, to ensure the desired precision andbias in test results.6
33、.1.3 The cross-sectional area of the specimen should be smallest at the center of the reduced section to ensure fracture withinthe gage length. For this reason, a small taper is permitted in the reduced section of each of the specimens described in thefollowing sections.FIG. 4 Gripping Devices for S
34、heet and Wire SpecimensFIG. 5 Snubbing Device for Testing WireB557M 1546.1.4 Rectangular specimens shall be 12.50 mm wide in accordance with Fig. 6 or Fig. 7 (for tubular products), and shall beof the full thickness of the material when practical. When necessary, 6.00-mm wide subsize specimens as sh
35、own in Fig. 6 may beused, but elongation values from such specimens are not applicable to specification requirements.6.1.4.1 Pin ends as shown in Fig. 8 may be used. In order to avoid buckling in tests of thin and high-strength materials, it maybe necessary to use stiffening plates at the grip ends.
36、6.1.5 Round specimens shall be the standard 12.50-mm diameter specimen in Fig. 9, except when the dimensions of the productmake this impossible. In such cases, small-size specimens proportional to the standard specimen shown in Fig. 9 may be used.Unless otherwise specified in the product specificati
37、on, the selection of round tensile specimens shall be as specified in Table 1.Unless permitted by the product specification, the diameter of the reduced section of the smallest specimen used shall not be lessthan 4 mm for wrought products and 6 mm for cast products.6.1.5.1 The shape of the ends of t
38、he specimen outside of the gage length shall be suitable to the material and of a shape to fitthe holders or grips of the testing machine so that the loads are applied axially. Fig. 10 shows specimens with various types of endsthat have given satisfactory results.6.1.6 Special care is required in th
39、e manufacture and testing of smaller specimens because the effects of machining (forexample, the amount of end load applied and the amount of heat generated) and testing (for example, eccentricity and gagemarking) variables are greater upon them than upon larger specimens. Therefore, the largest pra
40、ctical specimen shall always beused. With some types of materials, notably castings, the result of tests of small specimens may be more variable due to theincreasing significance of variations in metallic structure or the character of the surfaces. Low values derived from small specimensshould be ca
41、refully evaluated in accordance with 8.1 to be certain that the results are valid.6.1.7 While tensile strengths and yield strengths can properly be compared with results derived from test specimens of variousdimensions, elongation values may vary with specimen size and type. Therefore, elongation va
42、lues should be obtained withspecimens of the type from which the published tensile properties were established.6.2 Type, Direction, and Location in Wrought ProductsThis paragraph and subparagraphs provide the standard requirementsfor the testing of wrought products for the purpose of quality control
43、 and lot release testing. Additions or exceptions to theserequirements may need to be made in individual specifications for a particular material or product.Dimensions, mmStandard Specimen Sheet-Type12.5 mm Wide Subsize Specimen 6 mm WideGgage length 50.0 0.1 25.0 0.1WWidth (Note 1 and Note 2) 12.5
44、0.2 6.0 0.1TThickness (Note 3) thickness of material thickness of materialRRadius of fillet, min 12.5 6LOverall length, min (Note 4) 200 100ALength of reduced section, min 57 32BLength of grip section, min (Note 5) 50 30CWidth of grip section, approximate (Note 2 and Note 6) 20 10NOTE 1The ends of t
45、he reduced section shall not differ in width by more than 0.06 mm for the 50.00-mm gage length specimen or 0.025 mm forthe 25.00-mm gage length specimen. There may be a gradual taper in width from the ends of the reduced section to the center, but the width at each endshall not be more than 1 % grea
46、ter than the width at the center.NOTE 2For each of the specimens, narrower widths (W and C) may be used when necessary. In such cases the width of the reduced section shouldbe as large as the width of the material being tested permits: however, unless stated specifically, the requirements for elonga
47、tion in a product specificationshall not apply when these narrower specimens are used. If the width of the material is less than W, the sides may be parallel throughout the length ofthe specimen.NOTE 3The dimension T is the thickness of the test specimen as stated in the applicable material specific
48、ations. Maximum nominal thicknesses of12.5-mm and 6-mm wide specimens shall be 12.5 mm and 6 mm, respectively.NOTE 4To aid in obtaining axial loading during testing of 6-mm wide specimens, the overall length should be as large as the material will permit,up to 200 mm.NOTE 5It is desirable, if possib
49、le, to make the length of the grip section large enough to allow the specimen to extend into the grips a distance equalto two thirds or more of the length of the grips. If the thickness of 12.5-mm wide specimens is over 9 mm, longer grips and correspondingly longer gripsections of the specimens may be necessary to prevent failure in the grip section.NOTE 6The grip-end centerline of the 12.5-mm wide and 6-mm wide specimens shall coincide with the centerline of the reduced section within 0.2mm and 0.1 mm, respectively.FIG. 6 Rectangular T
