1、Designation: A370 12 A370 12aStandard Test Methods and Definitions forMechanical Testing of Steel Products1This standard is issued under the fixed designation A370; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. 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 Department of Defense.1. Scope*1.1 These test methods2 cover procedures and d
3、efinitions for the mechanical testing of steels, stainless steels, and related alloys.The various mechanical tests herein described are used to determine properties required in the product specifications. Variationsin testing methods are to be avoided, and standard methods of testing are to be follo
4、wed to obtain reproducible and comparableresults. In those cases in which the testing requirements for certain products are unique or at variance with these generalprocedures, the product specification testing requirements shall control.1.2 The following mechanical tests are described:SectionsTensio
5、n 5 to 13Tension 6 to 14Bend 14Bend 15Hardness 15Hardness 16Brinell 16Brinell 17Rockwell 17Rockwell 18Portable 18Portable 19Impact 19 to 28Impact 20 to 29Keywords 29Keywords 301.3 Annexes covering details peculiar to certain products are appended to these test methods as follows:AnnexBar Products A1
6、.1Tubular Products Annex A2Fasteners Annex A3Round Wire Products Annex A4Significance 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
7、Steel Reinforcing Bars Annex A9Procedure for Use and Control of Heat-Cycle Simulation Annex A101.4 The values stated in inch-pound units are to be regarded as the standard.1.5 When this document is referenced in a metric product specification, the yield and tensile values may be determined ininch-po
8、und (ksi) units then converted into SI (MPa) units. The elongation determined in inch-pound gauge lengths of 2 or 8 in.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 yield
9、and tensile values may be determined in SI units then converted into1 These test methods and definitions are under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and are the direct responsibility ofSubcommittee A01.13 on Mechanical and Chemical Testing and Proces
10、sing Methods of Steel Products and Processes.Current edition approved March 15, 2012October 15, 2012. Published March 2012November 2012. Originally approved in 1953. Last previous edition approved in20112012 as A370 11a.A370 12. DOI: 10.1520/A0370-12.10.1520/A0370-12a.2 For ASME Boiler and Pressure
11、Vessel Code applications see related Specification SA-370 in Section II of that Code.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. Becauseit may not be technically possible to a
12、dequately 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 appears at the end of this standardCopyright AS
13、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1inch-pound units. The elongation determined in SI unit gauge lengths of 50 or 200 mm may be reported in inch-pound gaugelengths of 2 or 8 in., respectively, as applicable.1.6 Attention is directed t
14、o ISO/IEC 17025 when there may be a need for information on criteria for evaluation of testinglaboratories.1.7 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 a
15、nd health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3A623 Specification for Tin Mill Products, General RequirementsA623M Specification for Tin Mill Products, General Requirements MetricA703/A703M Specification for Steel
16、Castings, General Requirements, for Pressure-Containing PartsA781/A781M Specification for Castings, Steel and Alloy, Common Requirements, for General Industrial UseA833 Practice for Indentation Hardness of Metallic Materials by Comparison Hardness TestersE4 Practices for Force Verification of Testin
17、g MachinesE6 Terminology Relating to Methods of Mechanical TestingE8/E8M Test Methods for Tension Testing of Metallic MaterialsE10 Test Method for Brinell Hardness of Metallic MaterialsE18 Test Methods for Rockwell Hardness of Metallic MaterialsE23 Test Methods for Notched Bar Impact Testing of Meta
18、llic MaterialsE29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE83 Practice for Verification and Classification of Extensometer SystemsE110 Test Method for Indentation Hardness of Metallic Materials by Portable Hardness TestersE190 Test Method for Gu
19、ided Bend Test for Ductility of WeldsE290 Test Methods for Bend Testing of Material for Ductility2.2 ASME Document:4ASME Boiler and Pressure Vessel Code, Section VIII, Division I, Part UG-82.3 ISO Standard:5ISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories
20、3. Significance and Use3.1 The primary use of these test methods is testing to determine the specified mechanical properties of steel, stainless steel andrelated alloy products for the evaluation of conformance of such products to a material specification under the jurisdiction ofASTM Committee A01
21、and its subcommittees as designated by a purchaser in a purchase order or contract.3.1.1 These test methods may be and are used by other ASTM Committees and other standards writing bodies for the purposeof conformance testing.3.1.2 The material condition at the time of testing, sampling frequency, s
22、pecimen location and orientation, reportingrequirements, and other test parameters are contained in the pertinent material specification or in a General RequirementSpecification for the particular product form.3.1.3 Some material specifications require the use of additional test methods not describe
23、d herein; in such cases, the requiredtest method is described in that material specification or by reference to another appropriate test method standard.3.2 These test methods are also suitable to be used for testing of steel, stainless steel and related alloy materials for otherpurposes, such as in
24、coming material acceptance testing by the purchaser or evaluation of components after service exposure.3.2.1 As with any mechanical testing, deviations from either specification limits or expected as-manufactured properties canoccur for valid reasons besides deficiency of the original as-fabricated
25、product. These reasons include, but are not limited to:subsequent service degradation from environmental exposure (for example, temperature, corrosion); static or cyclic service stresseffects, mechanically-induced damage, material inhomogeneity, anisotropic structure, natural aging of select alloys,
26、 furtherprocessing not included in the specification, sampling limitations, and measuring equipment calibration uncertainty. There isstatistical variation in all aspects of mechanical testing and variations in test results from prior tests are expected. An understandingof possible reasons for deviat
27、ion from specified or expected test values should be applied in interpretation of test results.3 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Docum
28、ent Summary page on the ASTM website.4 Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Three Park Ave., New York, NY 10016-5990.5 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ans
29、i.org.A370 12a24. General Precautions4.1 Certain methods of fabrication, such as bending, forming, and welding, or operations involving heating, may affect theproperties of the material under test. Therefore, the product specifications cover the stage of manufacture at which mechanicaltesting is to
30、be performed. The properties shown by testing prior to fabrication may not necessarily be representative of the productafter it has been completely fabricated.4.2 Improper machining or preparation of test specimens may give erroneous results. Care should be exercised to assure goodworkmanship in mac
31、hining. Improperly machined specimens should be discarded and other specimens substituted.4.3 Flaws in the specimen may also affect results. If any test specimen develops flaws, the retest provision of the applicableproduct specification shall govern.4.4 If any test specimen fails because of mechani
32、cal reasons such as failure of testing equipment or improper specimenpreparation, it may be discarded and another specimen taken.5. Orientation of Test Specimens5.1 The terms “longitudinal test” and “transverse test” are used only in material specifications for wrought products and are notapplicable
33、 to castings. When such reference is made to a test coupon or test specimen, the following definitions apply:5.1.1 Longitudinal Test, unless specifically defined otherwise, signifies that the lengthwise axis of the specimen is parallel to thedirection of the greatest extension of the steel during ro
34、lling or forging. The stress applied to a longitudinal tension test specimenis in the direction of the greatest extension, and the axis of the fold of a longitudinal bend test specimen is at right angles to thedirection of greatest extension (Fig. 1, Fig. 2a, and 2b).5.1.2 Transverse Test, unless sp
35、ecifically defined otherwise, signifies that the lengthwise axis of the specimen is at right anglesto the direction of the greatest extension of the steel during rolling or forging. The stress applied to a transverse tension testspecimen is at right angles to the greatest extension, and the axis of
36、the fold of a transverse bend test specimen is parallel to thegreatest extension (Fig. 1).5.2 The terms “radial test” and “tangential test” are used in material specifications for some wrought circular products and arenot applicable to castings. When such reference is made to a test coupon or test s
37、pecimen, the following definitions apply:5.2.1 Radial Test, unless specifically defined otherwise, signifies that the lengthwise axis of the specimen is perpendicular to theaxis of the product and coincident with one of the radii of a circle drawn with a point on the axis of the product as a center
38、(Fig.2a).5.2.2 Tangential Test, unless specifically defined otherwise, signifies that the lengthwise axis of the specimen is perpendicularto a plane containing the axis of the product and tangent to a circle drawn with a point on the axis of the product as a center (Fig.2a, 2b, 2c, and 2d).FIG. 1 Th
39、e Relation of Test Coupons and Test Specimens to Rolling Direction or Extension (Applicable to General Wrought Products)A370 12a3TENSION TEST6. Description6.1 The tension test related to the mechanical testing of steel products subjects a machined or full-section specimen of thematerial under examin
40、ation to a measured load sufficient to cause rupture. The resulting properties sought are defined inTerminology E6.6.2 In general, the testing equipment and methods are given in Test Methods E8/E8M. However, there are certain exceptionsto Test Methods E8/E8M practices in the testing of steel, and th
41、ese are covered in these test methods.7. Terminology7.1 For definitions of terms pertaining to tension testing, including tensile strength, yield point, yield strength, elongation, andreduction of area, reference should be made to Terminology E6.FIG. 2 Location of Longitudinal Tension Test Specimens
42、 in Rings Cut from Tubular ProductsA370 12a48. Testing Apparatus and Operations8.1 Loading SystemsThere are two general types of loading systems, mechanical (screw power) and hydraulic. These differchiefly in the variability of the rate of load application. The older screw power machines are limited
43、 to a small number of fixedfree running crosshead speeds. Some modern screw power machines, and all hydraulic machines permit stepless variationthroughout the range of speeds.8.2 The tension testing machine shall be maintained in good operating condition, used only in the proper loading range, andca
44、librated periodically in accordance with the latest revision of Practices E4.NOTE 1Many machines are equipped with stress-strain recorders for autographic plotting of stress-strain curves. It should be noted that somerecorders have a load measuring component entirely separate from the load indicator
45、 of the testing machine. Such recorders are calibrated separately.8.3 LoadingIt is the function of the gripping or holding device of the testing machine to transmit the load from the heads ofthe machine to the specimen under test. The essential requirement is that the load shall be transmitted axial
46、ly. This implies thatthe centers of the action of the grips shall be in alignment, insofar as practicable, with the axis of the specimen at the beginningand during the test and that bending or twisting be held to a minimum. For specimens with a reduced section, gripping of thespecimen shall be restr
47、icted to the grip section. In the case of certain sections tested in full size, nonaxial loading is unavoidableand in such cases shall be permissible.8.4 Speed of TestingThe speed of testing shall not be greater than that at which load and strain readings can be madeaccurately. In production testing
48、, speed of testing is commonly expressed: (1) in terms of free running crosshead speed (rate ofmovement of the crosshead of the testing machine when not under load), (2) in terms of rate of separation of the two heads of thetesting machine under load, (3) in terms of rate of stressing the specimen,
49、or (4) in terms of rate of straining the specimen. Thefollowing limitations on the speed of testing are recommended as adequate for most steel products:NOTE 2Tension tests using closed-loop machines (with feedback control of rate) should not be performed using load control, as this mode of testingwill result in acceleration of the crosshead upon yielding and elevation of the measured yield strength.8.4.1 Any convenient speed of testing may be used up to one half the specified yield point or yield strength. When this pointis reached, the free-running rate of separatio
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