1、Designation:A1091/A1091M161Standard Specification forSteel Castings,Creep-Strength Enhanced Ferritic Alloy,forPressure-Containing Parts,Suitable for High TemperatureService1This standard is issued under the fixed designation A1091/A1091M;the number immediately following the designation indicates the
2、year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTETable 3 was editorially corrected in April 2017.1.Scope1.1 This
3、specification covers creep-strength enhanced alloysteel castings for valves,flanges,fittings,and other pressure-containing parts intended primarily for high-temperature ser-vice(see Note 1).However,they are not restricted to suchapplications,and the castings may be used for other applica-tions for w
4、hich the attributes of the material,as defined by thisspecification,are suitable.1.2 One grade of martensitic alloy steel,Grade C91,iscovered(see Note 2).It is provided in two classes,differenti-ated by the type of heat treatment after weld repairs.This andsimilar steels are characterized by a predo
5、minantly temperedmartensitic or tempered Bainitic microstructure that is stabi-lized by the precipitation of temper-resistant particles atvarious precipitate nucleation sites in the microstructure.Suchsteels are designed to have creep-rupture strengths significantlysuperior to those of alloys of nom
6、inally similar compositions,but in which the precipitates or nucleation sites are absent.Since this crucial difference cannot be revealed by room-temperature mechanical property tests,these alloys requiretighter controls on manufacturing and processing.NOTE1The grades covered by this specification r
7、epresent materialsthat are generally suitable for assembly with other castings or wroughtsteel parts by fusion welding.It is not intended to imply that these gradespossess equal degrees of weldability;therefore,it is the responsibility ofthe purchaser to establish a suitable welding technique.Since
8、these gradespossess varying degrees of suitability for high-temperature service,it isalso the responsibility of the purchaser to determine which grade shall befurnished,due consideration being given to the requirements of theapplicable construction codes.NOTE2The committee formulating this specifica
9、tion has included onegrade of material that is considered to represent a type of ferritic alloysteel suitable for valves,flanges,fittings,and other pressure-containingparts.Additional alloy steels will be considered for inclusion in thisspecification by the committee as the need becomes apparent.1.3
10、 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 sta
11、ndard.1.4 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 TechnicalBarrie
12、rs to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2A335/A335M Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature ServiceA703/A703M Specification for Steel Castings,GeneralRequirements,for Pressure-Containing PartsA802/A802M Practice for Steel Castings,Surface
13、Accep-tance Standards,Visual ExaminationA985/A985M Specification for Steel Investment CastingsGeneral Requirements,for Pressure-Containing PartsA999/A999M Specification for General Requirements forAlloy and Stainless Steel Pipe2.2 ANSI Standards3ANSI B46.1 Surface Texture2.3 ASME Boiler and Pressure
14、 Vessel Code4ASME Boiler and Pressure Vessel Code Section IASME Boiler and Pressure Vessel Code Section III1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.18 on Castings.Current editio
15、n approved May 1,2016.Published May 2016.DOI:10.1520/A1091_A1091M-16E01.2For 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 we
16、bsite.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.4Available from American Society of Mechanical Engineers(ASME),ASMEInternational Headquarters,Two Park Ave.,New York,NY 10016-5990,http:/www.asme.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 standardizati
