ASTM_A_833_-_08a_2014.pdf

Designation:A83308a(Reapproved 2014)Standard Practice forIndentation Hardness of Metallic Materials by ComparisonHardness Testers1This standard is issued under the fixed designation A833;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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.1.Scope1.1 This practice covers the determination of indentationhardness of metallic materials using comparison hardnesstesters.1.2 This practice applies only to those comparison hardnesstesters,normally portable,that use comparative test bars thathave been standardized according to Test Method E10 as abasis for comparison.1.3 Calibration of comparative test bars(rods),used forcomparison to determine hardness numbers,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 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety problems,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 Standards:2A370 Test Methods and Definitions for Mechanical Testingof Steel ProductsE10 Test Method for Brinell Hardness of Metallic Materials3.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 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 characteristics 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 thatthe 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,normally 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.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.4.1.4 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 made from steel hardened withinthe range of 60 to 67 HRC and shall be capable of being used1This practice is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloysand is the direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved Oct.1,2014.Published October 2014.Originallyapproved in 1984.Last previous edition approved in 2008 as A833 08a DOI:10.1520/A0833-08AR142For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 in a reasonable number of tests without incurring damage thatcould affect the results.Use of a tungsten carbide ball mayresult in fracture or spalling of the ball.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 microm-eter scale of the microscope,or other measuring devices usedfor measuring the impression diameter,shall be such as topermit the direct measuring of the diameter to 0.1 mm and theestimati