ASTM_A_838_-_18.pdf

Designation:A83818Standard Specification forFree-Machining Ferritic Stainless Soft Magnetic Alloy Barfor Relay Applications1This standard is issued under the fixed designation A838;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 specification covers free-machining ferritic stain-less soft magnetic alloy produced or supplied expressly incold-finished bar form for use in magnetic cores and other partsrequiring a high permeability,low-coercivity stainless steel.1.1.1 This specification does not cover either cast parts orparts produced by powder metallurgy techniques.1.2 Two specific alloy types are covered.The primaryconstituents are shown in Table 1.These types have corrosionresistance similar to AISI Type 430F and Type 430F,Specifi-cation A582/A582M.1.3 This specification covers only these alloy types suppliedin cold-finished bars in cross-sectional shapes such as rounds,squares,hexagons,and octagons with diameters(diagonals)greater than or equal to 6.35 mm(0.250 in.)and less than orequal to 41.5 mm(1.63 in.).21.4 Certain cold-finished round bar products are capable ofbeing supplied mill annealed to required magnetic propertiessuch as low coercivity.The size range that can be mill annealedis from 6.35 to 41.5 mm(0.250 to 1.63 in.).Other products ofthese alloys cannot be mill annealed to produce equivalentlylow coercivity;hence,the final machined parts should be heattreated as recommended by the producer.1.5 The values stated in SI units are to be regarded asstandard.The values given in parentheses are mathematicalconversions to customary(cgs-emu and inch-pound)unitswhich are provided for information only and are not consideredstandard.1.6 This standard does 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:3A34/A34M Practice for Sampling and Procurement Testingof Magnetic MaterialsA340 Terminology of Symbols and Definitions Relating toMagnetic TestingA341/A341M Test Method for Direct Current MagneticProperties of Soft Magnetic Materials Using D-C Per-meameters and the Point by Point(Ballistic)Test MethodsA582/A582M Specification for Free-Machining StainlessSteel BarsA596/A596M Test Method for Direct-Current MagneticProperties of Materials Using the Ballistic Method andRing SpecimensA773/A773M Test Method for Direct Current MagneticProperties of Low Coercivity Magnetic Materials UsingHysteresigraphsE1019 Test Methods for Determination of Carbon,Sulfur,Nitrogen,and Oxygen in Steel,Iron,Nickel,and CobaltAlloys by Various Combustion and Inert Gas FusionTechniques2.2 Other Standard:IEC Publication 60404-7 Methods of Measurement of theCoercivity of Magnetic Materials in an Open MagneticCircuit41This specification is under the jurisdiction of ASTM Committee A06 onMagnetic Properties and is the direct responsibility of Subcommittee A06.02 onMaterial Specifications.Current edition approved Oct.1,2018.Published October 2018.Originallyapproved in 1985.Last previous edition approved in 2013 as A838 02(2013).DOI:10.1520/A0838-18.2Other product forms can be supplied to the chemistries listed in this specifi-cation;however,all other requirements shall be subject to negotiation between theproducer and the user.3For 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.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 3.Terminology3.1 The terms and symbols used in this specification aredefined in Terminology A340.4.Classification4.1 Two specific alloy types are covered:4.2 Grades,Alloy Type 1The standard grades of this alloytype are distin