ASTM E18-2008 317 Standard Test Methods for Rockwell Hardness of Metallic Materials.pdf

1、Designation: E 18 08An American National StandardStandard Test Methods forRockwell Hardness of Metallic Materials1, 2This standard is issued under the fixed designation E 18; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year

2、 of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon (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 methods cover the determ

3、ination of theRockwell hardness and the Rockwell superficial hardness ofmetallic materials by the Rockwell indentation hardness prin-ciple. This standard provides the requirements for Rockwellhardness machines and the procedures for performing Rock-well hardness tests.1.2 This standard includes addi

4、tional requirements in an-nexes:Verification of Rockwell Hardness Testing Machines Annex A1Rockwell Hardness Standardizing Machines Annex A2Standardization of Rockwell Indenters Annex A3Standardization of Rockwell Hardness Test Blocks Annex A4Guidelines for Determining the Minimum Thickness of aTest

5、 PieceAnnex A5Hardness Value Corrections When Testing on ConvexCylindrical SurfacesAnnex A61.3 This standard includes nonmandatory information inappendixes which relates to the Rockwell hardness test.List of ASTM Standards Giving Hardness Values Corre-spondingto Tensile StrengthAppendix X1Examples o

6、f Procedures for Determining RockwellHardness UncertaintyAppendix X21.4 At the time the Rockwell hardness test was developed,the force levels were specified in units of kilograms-force (kgf)and the indenter ball diameters were specified in units of inches(in.). This standard specifies the units of f

7、orce and length in theInternational System of Units (SI); that is, force in Newtons(N) and length in millimeters (mm). However, because of thehistorical precedent and continued common usage, force valuesin kgf units and ball diameters in inch units are provided forinformation and much of the discuss

8、ion in this standard refersto these units.1.5 The test principles, testing procedures, and verificationprocedures are essentially identical for both the Rockwell andRockwell superficial hardness tests. The significant differencesbetween the two tests are that the test forces are smaller for theRockw

9、ell superficial test than for the Rockwell test. The sametype and size indenters may be used for either test, dependingon the scale being employed. Accordingly, throughout thisstandard, the term Rockwell will imply both Rockwell andRockwell superficial unless stated otherwise.1.6 This standard does

10、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 Documents2.1 ASTM Standa

11、rds:3A 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 623 Specification forTin Mill Products, General Require-mentsA 623M Specification for Tin Mill Products, General Re-quirements MetricB19 Specification for Cartridge Brass Sheet, Strip, Plate,Bar, and DisksB 36/B 36M Spe

12、cification for Brass Plate, Sheet, Strip,AndRolled BarB 96/B 96M Specification for Copper-Silicon Alloy Plate,Sheet, Strip, and Rolled Bar for General Purposes andPressure VesselsB 103/B 103M Specification for Phosphor Bronze Plate,Sheet, Strip, and Rolled BarB 121/B 121M Specification for Leaded Br

13、ass Plate, Sheet,Strip, and Rolled BarB 122/B 122M Specification for Copper-Nickel-Tin Alloy,Copper-Nickel-Zinc Alloy (Nickel Silver), and Copper-Nickel Alloy Plate, Sheet, Strip, and Rolled BarB 130 Specification for Commercial Bronze Strip for BulletJackets1These test methods are under the jurisdi

14、ction of ASTM Committee E28 onMechanical Testing and are the direct responsibility of Subcommittee E28.06 onIndentation Hardness Testing.Current edition approved Jan. 15, 2008. Published March 2008. Originallyapproved in 1932. Last previous edition approved in 2007 as E 18 07.2In this test method, t

15、he term Rockwell refers to an internationally recognizedtype of indentation hardness test as defined in Section 3, and not to the hardnesstesting equipment of a particular manufacturer.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceast

16、m.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United St

17、ates.B 134/B 134M Specification for Brass WireB 152/B 152M Specification for Copper Sheet, Strip, Plate,and Rolled BarB 370 Specification for Copper Sheet and Strip for BuildingConstructionE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE92 Test Meth

18、od for Vickers Hardness of Metallic Mate-rialsE 140 Hardness Conversion Tables for Metals RelationshipAmong Brinell Hardness, Vickers Hardness, RockwellHardness, Superficial Hardness, Knoop Hardness, andScleroscope HardnessE 384 Test Method for Microindentation Hardness of Ma-terialsE 691 Practice f

19、or Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 American Bearings Manufacturer Association Stan-dard:ABMA 10-1989 Metal Balls42.3 ISO Standards:ISO 6508-1 Metallic MaterialsRockwell Hardness TestPart 1: Test Method (scales A, B, C, D, E, F, G, H, K, N,T)5ISO/IEC

20、17011 ConformityAssessmentGeneral Require-ments for Accreditation Bodies Accrediting ConformityAssessment Bodies5ISO/IEC 17025 General Requirements for the Competenceof Testing and Calibration Laboratories52.4 Society of Automotive Engineers (SAE) Standard:SAE J417 Hardness Tests and Hardness Number

21、 Conver-sions63. Terminology and Equations3.1 Definitions:3.1.1 calibrationdetermination of the values of the sig-nificant parameters by comparison with values indicated by areference instrument or by a set of reference standards.3.1.2 verificationchecking or testing to assure conform-ance with the

22、specification.3.1.3 standardizationto bring in conformance to a knownstandard through verification or calibration.3.1.4 Rockwell hardness testan indentation hardness testusing a verified machine to force a diamond spheroconicalindenter or tungsten carbide (or steel) ball indenter, underspecified con

23、ditions, into the surface of the material under test,and to measure the difference in depth of the indentation as theforce on the indenter is increased from a specified preliminarytest force to a specified total test force and then returned to thepreliminary test force.3.1.5 Rockwell superficial har

24、dness testsame as the Rock-well hardness test except that smaller preliminary and total testforces are used with a shorter depth scale.3.1.6 Rockwell hardness numbera number derived fromthe net increase in the depth of indentation as the force on anindenter is increased from a specified preliminary

25、test force toa specified total test force and then returned to the preliminarytest force.3.1.7 Rockwell hardness machinea machine capable ofperforming a Rockwell hardness test and/or a Rockwell super-ficial hardness test and displaying the resulting Rockwellhardness number.3.1.7.1 Rockwell hardness

26、testing machinea Rockwellhardness machine used for general testing purposes.3.1.7.2 Rockwell hardness standardizing machinea Rock-well hardness machine used for the standardization of Rock-well hardness indenters, and for the standardization of Rock-well hardness test blocks. The standardizing machi

27、ne differsfrom a regular Rockwell hardness testing machine by havingtighter tolerances on certain parameters.3.2 Equations:3.2.1 The average H of a set of n hardness measurementsH1, H2,Hnis calculated as:H 5H11 H21 . 1 Hnn(1)3.2.2 The error E in the performance of a Rockwell hard-ness machine at eac

28、h hardness level, relative to a standardizedscale, is determined as:E 5 H HSTD(2)where:H = average of n hardness measurements H1, H2,Hnmade on a standardized test block as part of aperformance verification, andHSTD= certified average hardness value of the standard-ized test block.3.2.3 The repeatabi

29、lity R in the performance of a Rockwellhardness machine at each hardness level, under the particularverification conditions, is estimated by the range of n hardnessmeasurements made on a standardized test block as part of aperformance verification, defined as:R 5 Hmax Hmin(3)where:Hmax= highest hard

30、ness value, andHmin= lowest hardness value.4. Significance and Use4.1 The Rockwell hardness test is an empirical indentationhardness test that can provide useful information about metallicmaterials. This information may correlate to tensile strength,wear resistance, ductility, and other physical cha

31、racteristics ofmetallic materials, and may be useful in quality control andselection of materials.4.2 Rockwell hardness tests are considered satisfactory foracceptance testing of commercial shipments, and have beenused extensively in industry for this purpose.4Available from American Bearing Manufac

32、turers Association (ABMA), 2025M Street, NW, Suite 800, Washington, DC 20036.5Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.6Available from Society of Automotive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096

33、-0001, http:/www.sae.org.E180824.3 Rockwell hardness testing at a specific location on a partmay not represent the physical characteristics of the whole partor end product.4.4 Adherence to this standard test method provides trace-ability to national Rockwell hardness standards except as statedotherw

34、ise.5. Principles of Test and Apparatus5.1 Rockwell Hardness Test PrincipleThe general prin-ciple of the Rockwell indentation hardness test is illustrated inFig. 1. The test is divided into three steps of force applicationand removal.Step 1The indenter is brought into contact with the testspecimen,

35、and the preliminary test force F0is applied. Afterholding the preliminary test force for a specified dwell time,the baseline depth of indentation is measured.Step 2The force on the indenter is increased at acontrolled rate by the additional test force F1to achieve thetotal test force F. The total te

36、st force is held for a specifieddwell time.Step 3The additional test force is removed, returning tothe preliminary test force. After holding the preliminary testforce for a specified dwell time, the final depth of indentationis measured. The Rockwell hardness value is derived from thedifference h in

37、 the final and baseline indentation depths whileunder the preliminary test force. The preliminary test force isremoved and the indenter is removed from the test specimen.5.1.1 There are two general classifications of the Rockwelltest: the Rockwell hardness test and the Rockwell superficialhardness t

38、est. The significant difference between the two testclassifications is in the test forces that are used. For theRockwell hardness test, the preliminary test force is 10 kgf (98N) and the total test forces are 60 kgf (589 N), 100 kgf (981 N),and 150 kgf (1471 N). For the Rockwell superficial hardness

39、test, the preliminary test force is 3 kgf (29 N) and the total testforces are 15 kgf (147 N), 30 kgf (294 N), and 45 kgf (441 N).5.1.2 Indenters for the Rockwell hardness test include adiamond spheroconical indenter and tungsten carbide ballindenters of specified diameters.5.1.2.1 Steel indenter bal

40、ls may be used only for testing thinsheet tin mill products specified in Specifications A 623 andA 623M using the HR15T and HR30T scales with a diamondspot anvil. Testing of this product may give significantlydiffering results using a tungsten carbide ball as compared tohistorical test data using a

41、steel ball. The use of tungstencarbide balls provide an improvement to the Rockwell hard-ness test because of the tendency of steel balls to flatten withuse, which results in an erroneously elevated hardness value.The user is cautioned that Rockwell hardness tests comparingthe use of steel and tungs

42、ten carbide balls have been shown togive different results. For example, depending on the materialtested and its hardness level, Rockwell B scale tests using atungsten carbide ball indenter have given results approximatelyone Rockwell point lower than when a steel ball indenter isused.NOTE 1Previous

43、 editions of this standard have stated that the steelball was the standard type of Rockwell indenter ball. The tungsten carbideball is considered the standard type of Rockwell indenter ball. The use oftungsten carbide balls provide an improvement to the Rockwell hardnesstest because of the tendency

44、of steel balls to flatten with use, which resultsin an erroneously elevated hardness value. The user is cautioned thatRockwell hardness tests comparing the use of steel and tungsten carbideballs have been shown to give different results. For example, depending onthe material tested and its hardness

45、level, Rockwell B scale tests using atungsten carbide ball indenter have given results approximately oneRockwell point lower than when a steel ball indenter is used.5.1.3 The Rockwell hardness scales are defined by thecombinations of indenter and test forces that may be used. Thestandard Rockwell ha

46、rdness scales and typical applications ofthe scales are given in Tables 1 and 2. Rockwell hardnessvalues shall be determined and reported in accordance with oneof these standard scales.5.2 Calculation of the Rockwell Hardness NumberDuringa Rockwell test, the force on the indenter is increased from a

47、preliminary test force to a total test force, and then returned tothe preliminary test force. The difference in the two indentationdepth measurements, while under the preliminary test force, ismeasured as h (see Fig. 1).5.2.1 The unit measurement for h is mm. From the value ofh, the Rockwell hardnes

48、s number is derived. The Rockwellhardness number is calculated as:5.2.1.1 For scales using a diamond spheroconical indenter(see Tables 1 and 2):Rockwell Hardness 5 100 h0.002(4)Rockwell Superficial Hardness 5 100 h0.001(5)where h is in mm.5.2.1.2 For scales using a ball indenter (see Tables 1 and 2)

49、:Rockwell Hardness 5 130 h0.002(6)Rockwell Superficial Hardness 5 100 h0.001(7)where h is in mm.5.2.2 The Rockwell hardness number is an arbitrary num-ber, which, by method of calculation, results in a highernumber for harder material.5.2.3 Rockwell hardness values shall not be designated by anumber alone because it is necessary to indicate which indenterand forces have been employed in making the test (see TablesFIG. 1 Rockwell Hardness Test Method (Schematic Diagram)E180831 and 2). Rockwell hardness numbers shall be quoted with ascale symbol represe