1、Designation: B557 14B557 15Standard Test Methods forTension Testing Wrought and Cast Aluminum- andMagnesium-Alloy Products1This standard is issued under the fixed designation B557; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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 test methods co
3、ver 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 E8, which cover the tension testing of allmetallic materials.1.2 The values stated in inch-pound units are to be regarded
4、 as standard. No other units of measurement are included in thisstandard.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 appropriate safety and health practices and determine
5、the applicability of regulatorylimitations prior to use.NOTE 1Foil is sheet metal less than 0.0079 in. thick. There is an overlap in the thickness range 0.006 to 0.0079 in. defined for foil and sheet. Sheetproducts in this thickness range are supplied to sheet product specifications and foil product
6、s 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.NOTE 2A complete metric companion to Test Methods B557 has been developedTest Methods B5
7、57M; therefore, no metric equivalents arepresented in these test methods.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 Methods of Mechanical TestingE8 Test
8、 Methods for Tension Testing of Metallic MaterialsE29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE83 Practice for Verification and Classification of Extensometer SystemsE345 Test Methods of Tension Testing of Metallic FoilE691 Practice for Conducti
9、ng 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 relating to tension testing appearing in Terminology E6 shall
10、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 comparisons of materials, alloy development, quality control, and
11、 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, 2015. Published July 2014October 2015. Originally approv
12、ed in 1971. Last previous edition approved in 2010 asB557 10.B557 14. DOI: 10.1520/B0557-14.10.1520/B0557-15.2 For test methods of tension testing of aluminum foil, see Test Methods E345.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceas
13、tm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an 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. Becau
14、seit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appear
15、s at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 The results of tension tests of specimens machined to standardized dimensions from selected portions of a part or materialmay not totally represent the s
16、trength and ductility properties of the entire end product or its in-service behavior in differentenvironments.4.3 These test methods are considered satisfactory for acceptance testing of commercial shipments and have been usedextensively in the trade for this purpose.5. Apparatus5.1 Testing Machine
17、sMachines used for tension testing shall conform to the requirements of Practices E4. The forces usedin determining tensile strength and yield strength shall be within the verified force application range of the testing machine asdefined in Practices E4.5.2 Gripping Devices:5.2.1 GeneralVarious type
18、s of gripping devices may be used to transmit the measured load applied by the testing machineto the test specimens. To ensure axial tensile stress within the gage length, the axis of the test specimen must coincide with thecenterline of the heads of the testing machine. Any departure from this requ
19、irement may introduce bending stresses that are notincluded in the usual stress computation (load divided by cross-sectional area).NOTE 3The effect of this eccentric loading may be illustrated by calculating the bending moment and stress thus added. For a standard 0.500-in.diameter specimen, the str
20、ess increase is 1.5 percentage points for each 0.001 in. of eccentricity. This error increases to 2.24 percentage points/0.001 in.for a 0.350-in. diameter specimen and to 3.17 percentage points/0.001 in. for a 0.250-in. diameter specimen.NOTE 4Alignment methods are given in Practice E1012.5.2.2 Wedg
21、e GripsTesting machines usually are equipped with wedge grips. These wedge grips generally furnish asatisfactory means of gripping long specimens of ductile metal. If, however, for any reason, one grip of a pair advances fartherthan the other as the grips tighten, an undesirable bending stress may b
22、e introduced. When liners are used behind the wedges, theymust be of the same thickness and their faces must be flat and parallel. For best results, the wedges should be supported over theirentire length by the heads of the testing machine. This requires that liners of several thicknesses be availab
23、le to cover the rangeof specimen thickness. For proper gripping, it is desirable that the entire length of the serrated face of each wedge be in contactwith the specimen. Proper alignment of wedge grips and liners is illustrated in Fig. 1. For short specimens it is generally necessaryto use machined
24、 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 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
25、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 shouldbe attached to the heads of the testing machine through properly lubricated spherical-seated bearings. The distance betweenspherical bear
26、ings should be as great as feasible.5.2.4 Grips for Sheet MaterialsThe self-adjusting grips shown in Fig. 4 have proved satisfactory for testing sheet materialsthat 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 sho
27、wn 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 dimensions shall be accurate andprecise to at least one half the smallest unit to which the individual dimension is required to be measured.5.4 Ex
28、tensometersExtensometers used in tensile testing shall conform to the requirements of Practice E83 for theclassifications specified by the procedure section of these test methods. Extensometers shall be used and verified to include thestrains corresponding to the yield strength and elongation at fra
29、cture (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 the accompanying figures) may be used to determine the yield behavior. For measuring elongation at fracturewith an appropriate extensomet
30、er, 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 SpecimensB557 152FIG. 2 Gripping Device for Threaded-End SpecimensFIG. 3 Gripping Device for Shouldered-End SpecimensB557 1536. Test Specime
31、n6.1 General:6.1.1 Test specimens shall be of the full section of the material whenever practical. Otherwise, machined specimens ofrectangular or round cross section shall be used.6.1.2 Improperly prepared test specimens often are the reason for unsatisfactory and incorrect test results. It is impor
32、tant,therefore, that care be exercised in the preparation of specimens, particularly in the machining, to ensure the desired precision andbias in test results.6.1.3 The cross-sectional area of the specimen should be smallest at the center of the reduced section to ensure fracture withinthe gage leng
33、th. 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 Sheet and Wire SpecimensFIG. 5 Snubbing Device for Testing WireB557 1546.1.4 Rectangular specimens shall be 0.500 in. wide in accordance with
34、 Fig. 6 or Fig. 7 (for tubular products), and shall be ofthe full thickness of the material when practical. When necessary, 0.250-in. wide subsize specimens as shown in Fig. 6 may beused, but elongation values from such specimens are not applicable to specification requirements.6.1.4.1 Pin ends as s
35、hown 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.6.1.5 Round specimens shall be the standard 0.500-in. diameter specimen in Fig. 9, except when the dimensions of the productmake this impo
36、ssible. In such cases, small-size specimens proportional to the standard specimen shown in Fig. 9 may be used.Unless otherwise specified in the product specification, the selection of round tension specimens shall be as specified in Table 1.Unless permitted by the product specification, the dimensio
37、ns of the smallest specimen used shall not be less than the following:Wrought CastDiameter of reduced section, in. 0.160 0.250Length of reduced section, in. 34 114Radius of fillet, in. 18 316Diameter of end section, in. 1564 38Overall length, in.With shouldered ends 112 238With threaded ends 2 3With
38、 plain cylindrical ends 3 46.1.5.1 The shape of the ends of the specimens 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 g
39、iven satisfactory results.6.1.6 Special care is required in the 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 up
40、on them than upon larger specimens. Therefore, the largest practical specimen shall always beused. With some types of materials, notably castings, the result of tests of small specimens may be more variable due to theDimensions, in.Standard Specimen Sheet-Type, 12-in. WideSubsize Specimen14-in. Wide
41、GGage length 2.000 0.005 1.000 0.003WWidth (Note 1 and Note 2) 0.500 0.010 0.250 0.002TThickness (Note 3) thickness of material thickness of materialRRadius of fillet, minLOverall length, min (Note 4)128144ALength of reduced section, min 214 114BLength of grip section, min (Note 5) 2 114CWidth of gr
42、ip section, approximate(Note 2 and Note 6)34 38NOTE 1The ends of the reduced section shall not differ in width by more than 0.002 in. for the 2.00-in. gage length specimen or 0.001 in. for the1.00-in. gage length specimen. There may be a gradual taper in width from the ends of the reduced section to
43、 the center, but the width at each end shallnot be more than 1 % greater 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 perm
44、its; however, unless stated specifically, the requirements for elongation 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 thickne
45、ss of the test specimen as stated in the applicable material specifications. Maximum nominal thicknesses of12-in. and 14-in. wide specimens shall be 12 in. and 14 in., respectively.NOTE 4To aid in obtaining axial loading during testing of 14-in. wide specimens, the overall length should be as large
46、as the material will permit,up to 8 in.NOTE 5It 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 equalto two thirds or more of the length of the grips. If the thickness of 12-in. wide specimens is over 38 in., lo
47、nger grips and correspondingly longer gripsections of the specimen may be necessary to prevent failure in the grip section.NOTE 6The grip-end centerline of the 12 in. wide and 14 in. wide specimens shall coincide with the centerline of the reduced section within 0.01and 0.005 in., respectively.FIG.
48、6 Rectangular Tension Test SpecimensB557 155increasing significance of variations in metallic structure or the character of the surfaces. Low values derived from small specimensshould be carefully evaluated in accordance with 8.1 to be certain that the results are valid.6.1.7 While tensile strengths
49、 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 values should be obtained withspecimens of the type from which the published tensile properties were established.Dimensions, in.GGage length 2.000 0.005WWidth (Note 1) 0.500 0.010TMeasured thickness of specimen Note 2RRadius of fillet, min 12ALength of reduced section, min 214BLength of grip section, min (Note 3) 3
