1、Designation: A 370 08aStandard Test Methods and Definitions forMechanical Testing of Steel Products1This standard is issued under the fixed designation A 370; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio
2、n. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 These test methods2cover procedures and definit
3、ionsfor the mechanical testing of wrought and cast steels, stainlesssteels, and related alloys. The various mechanical tests hereindescribed are used to determine properties required in theproduct specifications. Variations in testing methods are to beavoided, and standard methods of testing are to
4、be followed toobtain reproducible and comparable results. In those cases inwhich the testing requirements for certain products are uniqueor at variance with these general procedures, the productspecification testing requirements shall control.1.2 The following mechanical tests are described:Sections
5、Tension 5 to 13Bend 14Hardness 15Brinell 16Rockwell 17Portable 18Impact 19 to 28Keywords 291.3 Annexes covering details peculiar to certain productsare appended to these test methods as follows:AnnexBar Products A1.1Tubular Products Annex A2Fasteners Annex A3Round Wire Products Annex A4Significance
6、of Notched-Bar Impact Testing Annex A5Converting Percentage Elongation of Round Specimens toEquivalents for Flat SpecimensAnnex A6Testing Multi-Wire Strand Annex A7Rounding of Test Data Annex A8Methods for Testing Steel Reinforcing Bars Annex A9Procedure for Use and Control of Heat-Cycle Simulation
7、Annex A101.4 The values stated in inch-pound units are to be regardedas the standard.1.5 When this document is referenced in a metric productspecification, the yield and tensile values may be determined ininch-pound (ksi) units then converted into SI (MPa) units. Theelongation determined in inch-pou
8、nd gauge lengths of 2 or 8in. may be reported in SI unit gauge lengths of 50 or 200 mm,respectively, as applicable. Conversely, when this document isreferenced in an inch-pound product specification, the yieldand tensile values may be determined in SI units then con-verted into inch-pound units. The
9、 elongation determined in SIunit gauge lengths of 50 or 200 mm may be reported ininch-pound gauge lengths of 2 or 8 in., respectively, asapplicable.1.6 Attention is directed to ISO/IEC 17025 and E 1595when there may be a need for information on criteria forevaluation of testing laboratories.1.7 This
10、 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 applica-bility of regulatory limitations prior to use.2. Referenced Documents
11、2.1 ASTM Standards:3A 703/A 703M Specification for Steel Castings, GeneralRequirements, for Pressure-Containing PartsA 781/A 781M Specification for Castings, Steel and Alloy,Common Requirements, for General Industrial UseA 833 Practice for Indentation Hardness of Metallic Mate-rials by Comparison Ha
12、rdness TestersE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical Test-ingE8 Test Methods for Tension Testing of Metallic MaterialsE8M Test Methods for Tension Testing of Metallic Mate-rials Metric4E10 Test Method for Brinell Hardness of Metallic M
13、ateri-alsE18 Test Methods for Rockwell Hardness of MetallicMaterials1These test methods and definitions are under the jurisdiction of ASTMCommittee A01 on Steel, Stainless Steel and Related Alloys and are the directresponsibility of Subcommittee A01.13 on Mechanical and Chemical Testing andProcessin
14、g Methods of Steel Products and Processes.Current edition approved April 15, 2008. Published May 2008. Originallyapproved in 1953. Last previous edition approved in 2008 as A 370 08.2For ASME Boiler and Pressure Vessel Code applications see related Specifi-cation SA-370 in Section II of that Code.3F
15、or referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Withdrawn.1*A Summary of Changes section appears at the end of
16、 this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E23 Test Methods for Notched Bar Impact Testing ofMetallic MaterialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE83 P
17、ractice for Verification and Classification of Exten-someter SystemsE110 Test Method for Indentation Hardness of MetallicMaterials by Portable Hardness TestersE 190 Test Method for Guided Bend Test for Ductility ofWeldsE 290 Test Methods for Bend Testing of Material forDuctilityE 1595 Practice for E
18、valuating the Performance of Me-chanical Testing Laboratories42.2 ASME Document:5ASME Boiler and Pressure Vessel Code, Section VIII,Division I, Part UG-82.3 ISO Standard:6ISO/IEC 17025 General Requirements for the Competenceof Testing and Calibration Laboratories3. General Precautions3.1 Certain met
19、hods of fabrication, such as bending, form-ing, and welding, or operations involving heating, may affectthe properties of the material under test. Therefore, the productspecifications cover the stage of manufacture at which me-chanical testing is to be performed. The properties shown bytesting prior
20、 to fabrication may not necessarily be representa-tive of the product after it has been completely fabricated.3.2 Improper machining or preparation of test specimensmay give erroneous results. Care should be exercised to assuregood workmanship in machining. Improperly machined speci-mens should be d
21、iscarded and other specimens substituted.3.3 Flaws in the specimen may also affect results. If any testspecimen develops flaws, the retest provision of the applicableproduct specification shall govern.3.4 If any test specimen fails because of mechanical reasonssuch as failure of testing equipment or
22、 improper specimenpreparation, it may be discarded and another specimen taken.4. Orientation of Test Specimens4.1 The terms “longitudinal test” and “transverse test” areused only in material specifications for wrought products andare not applicable to castings. When such reference is made toa test c
23、oupon or test specimen, the following definitions apply:4.1.1 Longitudinal Test, unless specifically defined other-wise, signifies that the lengthwise axis of the specimen isparallel to the direction of the greatest extension of the steelduring rolling or forging. The stress applied to a longitudina
24、ltension test specimen is in the direction of the greatestextension, and the axis of the fold of a longitudinal bend testspecimen is at right angles to the direction of greatest extension(Fig. 1, Fig. 2a, and 2b).4.1.2 Transverse Test, unless specifically defined otherwise,signifies that the lengthw
25、ise axis of the specimen is at rightangles to the direction of the greatest extension of the steelduring rolling or forging. The stress applied to a transversetension test specimen is at right angles to the greatest exten-sion, and the axis of the fold of a transverse bend test specimenis parallel t
26、o the greatest extension (Fig. 1).4.2 The terms “radial test” and “tangential test” are used inmaterial specifications for some wrought circular products andare not applicable to castings. When such reference is made toa test coupon or test specimen, the following definitions apply:4.2.1 Radial Test
27、, unless specifically defined otherwise,signifies that the lengthwise axis of the specimen is perpen-dicular to the axis of the product and coincident with one of theradii of a circle drawn with a point on the axis of the productas a center (Fig. 2a).4.2.2 Tangential Test, unless specifically define
28、d otherwise,signifies that the lengthwise axis of the specimen is perpen-dicular to a plane containing the axis of the product and tangentto a circle drawn with a point on the axis of the product as acenter (Fig. 2a, 2b, 2c, and 2d).TENSION TEST5. Description5.1 The tension test related to the mecha
29、nical testing of steelproducts subjects a machined or full-section specimen of thematerial under examination to a measured load sufficient tocause rupture. The resulting properties sought are defined inTerminology E6.5.2 In general, the testing equipment and methods are givenin Test Methods E8. Howe
30、ver, there are certain exceptions toTest Methods E8practices in the testing of steel, and these arecovered in these test methods.5Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990.6Available from American National
31、 Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.FIG. 1 The Relation of Test Coupons and Test Specimens toRolling Direction or Extension (Applicable to General WroughtProducts)A 370 08a26. Terminology6.1 For definitions of terms pertaining to tension test
32、ing,including tensile strength, yield point, yield strength, elonga-tion, and reduction of area, reference should be made toTerminology E6.7. Testing Apparatus and Operations7.1 Loading SystemsThere are two general types of load-ing systems, mechanical (screw power) and hydraulic. Thesediffer chiefl
33、y in the variability of the rate of load application.The older screw power machines are limited to a small numberof fixed free running crosshead speeds. Some modern screwpower machines, and all hydraulic machines permit steplessvariation throughout the range of speeds.7.2 The tension testing machine
34、 shall be maintained in goodoperating condition, used only in the proper loading range, andcalibrated periodically in accordance with the latest revision ofPractices E4.NOTE 1Many machines are equipped with stress-strain recorders forautographic plotting of stress-strain curves. It should be noted t
35、hat somerecorders have a load measuring component entirely separate from theload indicator of the testing machine. Such recorders are calibratedseparately.7.3 LoadingIt is the function of the gripping or holdingdevice of the testing machine to transmit the load from theheads of the machine to the sp
36、ecimen under test. The essentialrequirement is that the load shall be transmitted axially. Thisimplies that the centers of the action of the grips shall be inalignment, insofar as practicable, with the axis of the specimenFIG. 2 Location of Longitudinal Tension Test Specimens in Rings Cut from Tubul
37、ar ProductsA 370 08a3at the beginning and during the test and that bending ortwisting be held to a minimum. For specimens with a reducedsection, gripping of the specimen shall be restricted to the gripsection. In the case of certain sections tested in full size,nonaxial loading is unavoidable and in
38、 such cases shall bepermissible.7.4 Speed of TestingThe speed of testing shall not begreater than that at which load and strain readings can be madeaccurately. In production testing, speed of testing is commonlyexpressed: (1) in terms of free running crosshead speed (rate ofmovement of the crosshead
39、 of the testing machine when notunder load), (2) in terms of rate of separation of the two headsof the testing machine under load, (3) in terms of rate ofstressing the specimen, or (4) in terms of rate of straining thespecimen. The following limitations on the speed of testing arerecommended as adeq
40、uate for most steel products:NOTE 2Tension tests using closed-loop machines (with feedbackcontrol of rate) should not be performed using load control, as this modeof testing will result in acceleration of the crosshead upon yielding andelevation of the measured yield strength.7.4.1 Any convenient sp
41、eed of testing may be used up toone half the specified yield point or yield strength. When thispoint is reached, the free-running rate of separation of thecrossheads shall be adjusted so as not to exceed116 in. per minper inch of reduced section, or the distance between the gripsfor test specimens n
42、ot having reduced sections. This speedshall be maintained through the yield point or yield strength. Indetermining the tensile strength, the free-running rate ofseparation of the heads shall not exceed12 in. per min per inchof reduced section, or the distance between the grips for testspecimens not
43、having reduced sections. In any event, theminimum speed of testing shall not be less than110 thespecified maximum rates for determining yield point or yieldstrength and tensile strength.7.4.2 It shall be permissible to set the speed of the testingmachine by adjusting the free running crosshead speed
44、 to theabove specified values, inasmuch as the rate of separation ofheads under load at these machine settings is less than thespecified values of free running crosshead speed.7.4.3 As an alternative, if the machine is equipped with adevice to indicate the rate of loading, the speed of the machinefr
45、om half the specified yield point or yield strength through theyield point or yield strength may be adjusted so that the rate ofstressing does not exceed 100 000 psi (690 MPa)/min. How-ever, the minimum rate of stressing shall not be less than10 000 psi (70 MPa)/min.8. Test Specimen Parameters8.1 Se
46、lectionTest coupons shall be selected in accordancewith the applicable product specifications.8.1.1 Wrought SteelsWrought steel products are usuallytested in the longitudinal direction, but in some cases, wheresize permits and the service justifies it, testing is in thetransverse, radial, or tangent
47、ial directions (see Fig. 1 and Fig.2).8.1.2 Forged SteelsFor open die forgings, the metal fortension testing is usually provided by allowing extensions orprolongations on one or both ends of the forgings, either on allor a representative number as provided by the applicableproduct specifications. Te
48、st specimens are normally taken atmid-radius. Certain product specifications permit the use of arepresentative bar or the destruction of a production part fortest purposes. For ring or disk-like forgings test metal isprovided by increasing the diameter, thickness, or length of theforging. Upset disk
49、 or ring forgings, which are worked orextended by forging in a direction perpendicular to the axis ofthe forging, usually have their principal extension alongconcentric circles and for such forgings tangential tensionspecimens are obtained from extra metal on the periphery orend of the forging. For some forgings, such as rotors, radialtension tests are required. In such cases the specimens are cutor trepanned from specified locations.8.1.3 Cast SteelsTest coupons for castings from whichtension test specimens are prepared shall be in accordance withthe requirements of
