ASTM A833-2008 Standard Practice for Indentation Hardness of Metallic Materials by Comparison Hardness Testers.pdf

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1、Designation: A 833 08Standard Practice forIndentation Hardness of Metallic Materials by ComparisonHardness Testers1This standard is issued under the fixed designation A 833; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year

2、of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice covers the determination of indentationhardness of metallic materials using comparison hardnesstest

3、ers.1.2 This practice applies only to those comparison hardnesstesters, normally portable, that use comparative test bars thathave been standardized according to Test Method E10as abasis for comparison.1.3 Calibration of comparative test bars (rods), used forcomparison to determine hardness numbers,

4、 is also covered bythis practice.1.4 The impression force used during comparison hardnesstesting is normally an impact load applied by striking ahammer on the appropriate areas as outlined in the manufac-turers instructions.1.5 This standard does not purport to address all of thesafety problems, if

5、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 Standards:2A 370 Test Methods and Definitions for Mechanica

6、l Testingof Steel ProductsE10 Test Method for Brinell Hardness of Metallic Materi-als3. Significance and Use3.1 The comparative hardness test is an empirical dynamicindentation hardness test. Comparative hardness tests provideuseful information about metallic materials. This informationmay correlate

7、 to tensile strength, wear resistance, ductility, heattreatment condition, or other physical characteristics of metal-lic materials, and may be useful in quality control and selectionof materials.3.2 Comparative hardness testing at a specific location on apart may not represent the physical characte

8、ristics of the wholepart or end product.4. Apparatus4.1 Comparison hardness testers are used principally fortesting articles that are too large or unwieldy to be tested in theusual types of testing machines, for testing parts of fixedstructures, or for testing under any conditions that require thatt

9、he indenting force be applied in a direction other than vertical.4.1.1 Required equipment includes an apparatus that con-tains the impression ball and a slot or spacing to insert thecomparative test bar (rod), the comparative test bar, a structureto apply the impact (anvil), and an impacting tool, n

10、ormally ahammer. This apparatus is designed to allow a ball impressionto be produced on the standard rod simultaneously with oneproduced on the piece to be tested. Comparison of theimpression diameters together with the hardness of the com-parative bar (rod) is used to determine hardness of the part

11、.4.1.2 The structure to convey the impact to the test bar,impression ball, and part being tested is designed with thestriking surface for the impacting tool centered directly abovethe location of the impression ball.4.1.3 The apparatus may also be designed to include anextension for stabilization.4.

12、1.4 The Brinell hardness of the comparison test bar (rod)used should be within 615% of the anticipated Brinellhardness of the part being tested, and of the same general typeof material.4.1.5 Impression Ball:4.1.5.1 The diameter of the impression ball shall be 10 60.01 mm.4.1.5.2 The ball shall be ma

13、de from hardened steel and shallbe capable of being used in a reasonable number of testswithout incurring damage that could affect the results. Use ofa tungsten carbide ball may result in fracture or spalling of theball.1This practice is under the jurisdiction of ASTM Committee A01 on Steel,Stainles

14、s Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved March 1, 2008. Published March 2008. Originallyapproved in 1984. Last previous edition approved in 2001 as A 833 84 (2001).2For referenced ASTM standards, visit th

15、e 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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100

16、Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.1.5.3 The ball shall be inspected regularly according to theequipment manufacturers recommendations to ensure accu-racy.4.2 Measuring MicroscopeThe divisions of the microme-ter scale of the microscope, or other measuri

17、ng devices usedfor measuring the impression diameter, shall be such as topermit the direct measuring of the diameter to 0.1 mm and theestimation of the diameter to 0.05 mm.5. Test Parts5.1 Parts tested by this hardness testing practice vary greatlyin form since it is frequently desirable to make the

18、 impressionupon a part to be used in the finished product rather than upona sample test specimen.5.1.1 DimensionsThe thickness of the tested part shall besuch that no bulge or other marking showing the effect of theload appears on the side of the piece opposite the impression.In any event, the thick

19、ness of the part shall be at least ten timesthe depth of the indentation. The minimum width shall be atleast two and one half times the diameter of the indentation.5.1.2 FinishWhen necessary, the surface on which theimpression is to be made shall be filed, ground, machined, orpolished with abrasive

20、material so that the edge of theimpression shall be defined clearly enough to permit themeasurement of the diameter to the specified accuracy. Takecare to avoid overheating or cold working the surface. Suffi-cient metal shall be removed to eliminate decarburized metal.5.2 SupportAll parts to be test

21、ed shall be adequatelysupported to prevent any movement or deflection duringapplication of the impact load.6. Verification of Apparatus and Calibration of Test Bars6.1 Verification of ApparatusThe hardness-testing appa-ratus (including test bars) shall be verified by performing testson Brinell block

22、s that have been standardized according to therequirements of Test Method E10.6.1.1 Full verification of the apparatus shall be performedprior to use when new, and upon replacement of the impressionball. The full verification shall include testing at least oneBrinell test block 3 times. The average

23、of the three measure-ments shall be within 65 % of the Brinell value of the testblock.6.1.2 Periodic verifications are recommended at the begin-ning of each day the comparative tester is used, or during usageas deemed necessary. Periodic verifications should be per-formed using Brinell test blocks w

24、ithin 615 % of the expectedBrinell hardness of the parts being tested. One measurement issatisfactory for periodic testing. The result of the periodic testmeasurement should be within 65 % of the Brinell value of thetest block to be considered to be in compliance with thispractice.6.2 Calibration of

25、 Comparative BarsThe Brinell hardnessof the comparative test bars shall be determined by the test barmanufacturer using a 10 mm diameter ball and a 3000 kg loadaccording to Test Method E10on each of the four faces of thetest bar at approximately the mid-length of the bar. If the testbar is too soft

26、to permit the use of a 3000 kg load, then a1500 kg load shall be used. The hardness values obtained shallnot vary from each other by more than 62 %. The ends of thebar shall be permanently marked with the average hardnessvalue, as well as the applied load if the 1500 kg load was usedby the manufactu

27、rer prior to shipment.7. Procedure7.1 Assemble the comparative test bar into the apparatusmaking sure a minimum distance of no less than 5 mm willexist between diameter of the impression to be made and anyother indentations on the face. Minimum distance of theindentation diameter from the edge of th

28、e part tested shall be12.5 mm. If the apparatus is equipped with a presetting barstop, ensure the fixture is properly in place. Place the apparatuson the surface of the component to be tested and apply theimpact load using a 1 to 214 kg (2 to 5 lb) hammer. It isessential to apply a well guided, shor

29、t blow in order to avoid arebound and thus a double blow that may produce an erroneousresult by damaging the sharp edge of the ball impression.7.2 Impression DiameterThe diameter of the impressionproduced on the comparative test bar should not exceed 4.2mm. If a larger impression is produced, the co

30、mparative barmay give way laterally and the test result may be in error. Inthis case the use of the 1500-kg load should be considered (see6.2).7.3 MeasurementsTwo diameters of each impression atright angles to each other shall be measured to within 0.05 mmand their mean value used as the basis for s

31、ubsequent calcu-lations.7.3.1 If the two diameter measurements differ by more than0.1 mm, the readings shall be discarded in accordance withTest Methods and Definitions A 370, and the test repeated.7.4 Determination of Part HardnessEmploying the cali-bration device or mathematical equation supplied

32、by themanufacturer for the apparatus, determine the hardness of thepart by using both (test bar and part) impression diameters andthe hardness of the comparative bar in accordance with theequipment manufacturers instructions. Annex A1 gives detailsof typical formulae used in calculating the comparis

33、on hard-ness.8. Report8.1 The report shall include the following information:8.1.1 Indentation hardness number of the part or componentas calculated in 7.4 with the designation HBC and the Brinellhardness number of the comparative test bar,8.1.1.1 The result shall be written as shown in the followin

34、gexample:232HBC/240 where 232 is the hardness determined asdefined in 7.4 and 240 is the Brinell hardness of the compara-tive test bar.8.1.2 Identification of the manufacturers equipment, and8.1.3 Diameters of the impressions in the part or componentand comparative test bar.9. Keywords9.1 Brinell ha

35、rdness; comparative hardness; comparativehardness testers; metallicA833082ANNEXA1. ANALYTICAL HARDNESS DETERMINATIONA1.1 As an example, the hardness of the part being testedmay be determined from the following equation, based on theuse of a 10 mm diameter ball. However the manufacturer of theactual

36、apparatus used may use another formula for obtainingthe comparison hardness value as stated in 7.4.B15 B210 =100 D12!/10 =100 D22!where:B1= comparison hardness of the part being tested,B2= Brinell hardness of the comparative bar,D12= diameter of impression in the comparative bar,D22= diameter of imp

37、ression in the part being tested.SUMMARY OF CHANGESCommittee A01 has identified the location of selected changes to this standard since the last issue (A 833 84(2001) that may impact the use of this standard. (Approved March 1, 2008.)(1) General revision and addition of a significance and usesection

38、.(2) Impression ball dimensions and type added together withhammer weight range and a new Annex A1.(3) Reporting requirements revised.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standa

39、rd are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif

40、 not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, whi

41、ch you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).A833083