1、Designation: B557M 14Standard 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 revision
2、, 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 test method
3、s cover the tension testing of wroughtand cast aluminum- and magnesium-alloy products, exceptingaluminum foil2, and are derived from Test Methods E8M,which cover the tension testing of all metallic materials.NOTE 1These metric test methods are the equivalents of those in TestMethods B557, and are co
4、mpatible in technical content except for therequirement of longer gage lengths for round specimens.NOTE 2Exceptions to the provisions of these test methods may needto be made in individual specifications or test methods for a particularmaterial.1.2 The values stated in SI units are to be regarded as
5、standard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the
6、applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3B209 Specification for Aluminum and Aluminum-AlloySheet and PlateE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE8M Test Methods for Tensio
7、n Testing of Metallic MaterialsMetric (Withdrawn 2008)4E29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE83 Practice for Verification and Classification of Exten-someter SystemsE345 Test Methods of Tension Testing of Metallic FoilE691 Practice for Con
8、ducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1012 Practice for Verification of Testing Frame and Speci-men Alignment Under Tensile and Compressive AxialForce Application3. Terminology3.1 The definitions of terms relating to tension testingappearing in Terminology E6 sh
9、all be considered as applyingto the terms used in these test methods.4. Significance and Use4.1 Tension tests provide information on the strength andductility of materials under uniaxial tensile stresses. Thisinformation may be useful in comparisons of materials, alloydevelopment, quality control, a
10、nd design under certain circum-stances.4.2 The results of tension tests of specimens machined tostandardized dimensions from selected portions of a part ormaterial may not totally represent the strength and ductilityproperties of the entire end product or its in-service behavior indifferent environm
11、ents.4.3 These test methods are considered satisfactory for ac-ceptance testing of commercial shipments and have been usedextensively in the trade for this purpose.5. Apparatus5.1 Testing MachinesMachines used for tension testingshall conform to the requirements of Practices E4. The forcesused in de
12、termining tensile strength and yield strength shall bewithin the verified force application range of the testingmachine as defined in Practices E4.5.2 Gripping Devices:5.2.1 GeneralVarious types of gripping devices may beused to transmit the measured load applied by the testingmachine to the test sp
13、ecimens. To ensure axial tensile stress1These test methods are under the jurisdiction of ASTM Committee B07 onLight Metals and Alloys and are the direct responsibility of Subcommittee B07.05on Testing.Current edition approved May 15, 2014. Published July 2014. Originallyapproved in 1976. Last previo
14、us edition approved in 2010 as B557M 10. DOI:10.1520/B0557M-14.2For test methods of tension testing of aluminum foil, see Test Methods E345.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volum
15、e information, refer to the standards Document Summary page onthe ASTM website.4The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
16、onshohocken, PA 19428-2959. United States1within the gage length, the axis of the test specimen mustcoincide with the centerline of the heads of the testingmachine. Any departure from this requirement may introducebending stresses that are not included in the usual stresscomputation (load divided by
17、 cross-sectional area).NOTE 3The effect of this eccentric loading may be illustrated bycalculating the bending moment and stress thus added. For a standard12.50-mm diameter specimen, the stress increase is 1.5 percentage pointsfor each 0.025 mm of eccentricity. This error increases to about 2.3perce
18、ntage points/0.025 mm for a 9-mm diameter specimen and to 3.25percentage 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 equippedwith wedge grips. These wedge grips generally furnish asatisfactory means o
19、f gripping long bars of ductile metal. If,however, for any reason, one grip of a pair advances fartherthan the other as the grips tighten, an undesirable bendingstress may be introduced. When liners are used behind thewedges, they must be of the same thickness and their facesmust be flat and paralle
20、l. For best results, the wedges should besupported over their entire length by the heads of the testingmachine. This requires that liners of several thicknesses beavailable to cover the range of specimen thickness. For propergripping, it is desirable that the entire length of the serratedface of eac
21、h wedge be in contact with the specimen. Properalignment of wedge grips and liners is illustrated in Fig. 1. Forshort specimens it is generally necessary to use machined testspecimens and to use a special means of gripping to ensure thatthe specimens, when under load, shall be as nearly as possiblei
22、n uniformly distributed pure axial tension (see 5.2.3, 5.2.4, and5.2.5).5.2.3 Grips for Threaded and Shouldered SpecimensAschematic diagram of a gripping device for threaded-endspecimens is shown in Fig. 2, while Fig. 3 shows a device forgripping specimens with shouldered ends. Both of thesegripping
23、 devices should be attached to the heads of the testingmachine through properly lubricated spherical-seated bearings.The distance between spherical bearings should be as large asfeasible.5.2.4 Grips for Sheet MaterialsThe self-adjusting gripsshown in Fig. 4 have proved satisfactory for testing sheet
24、materials that cannot be tested satisfactorily in the usual type ofwedge grips.5.2.5 Grips for WireGrips of either the wedge or snubbingtypes as shown in Fig. 4 and Fig. 5 or flat wedge grips may beused.5.3 Dimension-Measuring DevicesMicrometers and otherdevices used for measuring linear dimensions
25、shall be accurateand precise to at least one half the smallest unit to which theindividual dimension is required to be measured.5.4 ExtensometersExtensometers used in tensile testingshall conform to the requirements of Practice E83 for theclassifications specified by the procedure section of these t
26、estmethods. Extensometers shall be used and verified to includethe strains corresponding to the yield strength and elongation atfracture (if determined).5.4.1 Extensometers with gage lengths equal to or shorterthan the nominal gage length of the specimen (dimensionshown as “G-gage Length” in the acc
27、ompanying figures) maybe used to determine the yield behavior. For measuringelongation at fracture with an appropriate extensometer, thegage length of the extensometer shall be equal to the nominalgage length required for the specimen being tested.6. Test Specimen6.1 General:6.1.1 Test specimens sha
28、ll be of the full section of thematerial whenever practical. Otherwise, machined specimensof rectangular or round cross section shall be used.FIG. 1 Wedge Grips with Liners for Flat SpecimensFIG. 2 Gripping Device for Threaded-End SpecimensB557M 1426.1.2 Improperly prepared test specimens often are
29、thereason for unsatisfactory and incorrect test results. It isimportant, therefore, that care be exercised in the preparationof specimens, particularly in the machining, to ensure thedesired precision and bias in test results.6.1.3 The cross-sectional area of the specimen should besmallest at the ce
30、nter of the reduced section to ensure fracturewithin the gage length. For this reason, a small taper ispermitted in the reduced section of each of the specimensdescribed in the following sections.6.1.4 Rectangular specimens shall be 12.50 mm wide inaccordance with Fig. 6 or Fig. 7 (for tubular produ
31、cts), andshall be of the full thickness of the material when practical.When necessary, 6.00-mm wide subsize specimens as shown inFig. 6 may be used, but elongation values from such specimensare not applicable to specification requirements.6.1.4.1 Pin ends as shown in Fig. 8 may be used. In order toa
32、void buckling in tests of thin and high-strength materials, itmay be necessary to use stiffening plates at the grip ends.6.1.5 Round specimens shall be the standard 12.50-mmdiameter specimen in Fig. 9, except when the dimensions of theproduct make this impossible. In such cases, small-size speci-men
33、s proportional to the standard specimen shown in Fig. 9may be used. Unless otherwise specified in the productspecification, the selection of round tensile specimens shall beas specified in Table 1. Unless permitted by the productspecification, the diameter of the reduced section of thesmallest speci
34、men used shall not be less than 4 mm for wroughtproducts and 6 mm for cast products.6.1.5.1 The shape of the ends of the specimen outside of thegage length shall be suitable to the material and of a shape tofit the holders or grips of the testing machine so that the loadsare applied axially. Fig. 10
35、 shows specimens with various typesof ends that have given satisfactory results.6.1.6 Special care is required in the manufacture and testingof smaller specimens because the effects of machining (forexample, the amount of end load applied and the amount ofheat generated) and testing (for example, ec
36、centricity and gagemarking) variables are greater upon them than upon largerspecimens. Therefore, the largest practical specimen shallalways be used. With some types of materials, notably castings,the result of tests of small specimens may be more variable dueto the increasing significance of variat
37、ions in metallic structureor the character of the surfaces. Low values derived from smallFIG. 3 Gripping Device for Shouldered-End SpecimensFIG. 4 Gripping Devices for Sheet and Wire SpecimensFIG. 5 Snubbing Device for Testing WireB557M 143Dimensions, mmStandard Specimen Sheet-Type12.5mmWideSubsize
38、Specimen 6 mm WideGgage length 50.0 0.1 25.0 0.1WWidth (Note 1 and Note 2) 12.5 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 30
39、CWidth of grip section, approximate (Note 2 and Note 6) 20 10NOTE 1The ends of the 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
40、 section to the center, but the width at each endshall not 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
41、tested permits: 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
42、the thickness of the test specimen as stated in the applicable material specifications. 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
43、 large as the material will permit,up to 200 mm.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 12.5-mm wide specimens is over
44、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, respectivel
45、y.FIG. 6 Rectangular Tension Test SpecimensDimensions, mmGgage length 50.00 0.10WWidth (Note 1) 12.50 0.25TMeasured thickness of specimen Note 2RRadius of fillet, min 12.5ALength of reduced section, min 57BLength of grip section, min (Note 3) 75CWidth of grip section, approximate (Note 4) 20NOTE 1Th
46、e ends of the reduced section shall not differ in width by more than 0.06 mm. There may be a gradual taper in width from the ends ofthe reduced section to the center, but the width at each end shall not be more than 1 % greater than the width at the center.NOTE 2The dimension T is the thickness of t
47、he tubular section as provided for in the applicable material specifications.NOTE 3It 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 equalto two thirds or more of the length of the grips.NOTE 4The grip-end cent
48、erline of the specimen shall coincide with the centerline of the reduced section within 1.00 mm.NOTE 5For circular segments, the cross-sectional area shall be calculated using the formula shown in 7.2.3.NOTE 6The radii of all fillets shall be equal to each other within a tolerance of 1.00 mm, and th
49、e centers of curvature of the two fillets at a particularend shall be located across from each other (on a line perpendicular to the centerline) within a tolerance of 2.00 mm.FIG. 7 Longitudinal Tension Specimens for Large-Diameter Tubular ProductsB557M 144specimens should be carefully evaluated in accordance with8.1 to be certain that the results are valid.6.1.7 While tensile strengths and yield strengths can prop-erly be compared with results derived from test specimens ofDimensions, mmGgage length 50.00 0.10WWidth (Note
