ASTM_A_942_-_A_942M_-_95_2012e1.pdf

Designation:A942/A942M95(Reapproved 2012)1Standard Specification forCentrifugally Cast White Iron/Gray Iron Dual Metal Abrasion-Resistant Roll Shells1This standard is issued under the fixed designation A942/A942M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEDesignation was converted to dual and editorial changes were made throughout in November 2013.1.Scope1.1 This specification covers double pour,centrifugally cast,abrasion-resistant roll shells for general application.The outerlayer is white iron and the inner layer is gray iron.There shallbe no gradient of mottled iron between the white iron and thegray iron.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.2.1 Within the text,the SI units are shown in brackets.2.Referenced Documents2.1 ASTM Standards:2A48/A48M Specification for Gray Iron CastingsE8 Test Methods for Tension Testing of Metallic MaterialsE10 Test Method for Brinell Hardness of Metallic Materials3.Classification3.1 The white iron portion of the casting shall be classifiedby type based upon Brinell Hardness.3.2 The gray iron portion of the casting shall be classified byclass based upon tensile strength.4.Ordering Information4.1 Orders for material to this specification shall include thefollowing:4.1.1 Specification title,designation,and year of issue,4.1.2 Quantity of castings required,4.1.3 Required dimensions and thickness of white iron layer(8.1),4.1.4 Surface conditionas cast or machined,4.1.5 Type of white iron required for the outer layer of thecasting(7.1),4.1.6 Class of gray iron required for the inner layer(7.2),4.1.7 Certification,if required(Section 13),and4.1.8 Special position of marking information,if required(Section 14).4.2 Additional requirements may be agreed upon betweenthe manufacturer and the purchaser.5.Materials and Manufacture5.1 Both the white and the gray irons may be melted by anysuitable melting process.5.2 The white iron portion of the casting shall be producedby chemistry rather than chilling.6.Chemical Composition6.1 A chemical analysis shall be performed by the manu-facturer on both the white and gray irons.The chemicalcompositions shall be controlled to obtain the required me-chanical properties.7.Mechanical Properties7.1 The white iron shall conform to the following require-ments:Type I 450 to 500 HBType II 500 to 550 HBType III 550 to 600 HBType IV 600 to 650 HB7.2 The gray iron shall conform to the following require-ments:Tensile StrengthClassmin,ksimin,MPaNo.2020138No.2525172No.3030207No.35352411This specification is under the jurisdiction of ASTM Committee A04 on IronCastings and is the direct responsibility of Subcommittee A04.01 on Grey and WhiteIron Castings.Current edition approved Oct.1,2012.Published November 2012.Originallyapproved in 1995.Last previous edition approved in 2007 as A942 95(2007).DOI:10.1520/A0942-95R12E01.2For 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 8.Other Requirements8.1 The thickness of the white iron layer shall be a mini-mum of12in.8.1.1 The thickness of the white iron layer shall be mea-sured on the roll face at each end and shall conform to thespecified thickness.9.Finish and Appearance9.1 All exterior surfaces shall be machined or ground priorto the rolls being placed into service.9.2 The manufacturer shall be responsible for providingcastings with adequate stock for final machining.9.3 Surfaces and corners of the machined castings shall befree from burrs and extremely sharp edges.9.4 Machined surfaces of the castings may be protected bythe application of a rust and corrosion preventive coating.10.Sampling10.1 Each casting shall be tested for chemical composition,hardness,and tensile strength.10.2 The white iron hardness shall be determined on cropends removed from the casting.10.3 The tension test of the gray iron shall be performed onspecimens obtained from separately cast test bars poured inaccordance with Specification A48/A48M.Standard test bar Bshall be the size of the test bar poured.10.4 Chemical analysis shall be performed on samplesobtained during pouring of the iron.11.Test Methods11.1 The hardness test shall be performed in accordancewith Test Method E10,using a 10-mm tungsten carbide balland 3000 kgf load.Test re