1、Designation:A35589(Reapproved 2012)Standard Specification forSteel Bars,Alloys,for Nitriding1This standard is issued under the fixed designation A355;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number
2、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 alloy steel bars,suitable forsurface hardening by nitriding,designated as Classes A,B,C,and D.Class A and Class D bars a
3、re general-purpose bars;Class B bars are free-machining bars;Class C bars contain3.50%nickel and are characterized by higher core strength.All classes are normally furnished in the hot-rolled,quenched,and tempered condition.However,centerless-ground or turnedbars,in any of the classes,may be specifi
4、ed by the purchaser.Also,as-rolled,annealed,or unannealed bars suitable forforging may be purchased to this specification.When as-rolled,annealed,or unannealed bars are furnished,Sections 6,10,and11 are not applicable.1.2 The values stated in inch-pound units are to be regardedas standard.The values
5、 given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.2.Referenced Documents2.1 ASTM Standards:2A29/A29M Specification for Steel Bars,Carbon and Alloy,Hot-Wrought,General Requirements for3.Ordering Information3.1 Orders un
6、der this specification should include the fol-lowing as required to adequately describe the desired materials:3.1.1 Quantity(weight or number of pieces),3.1.2 Name of material(alloy steel bars,for nitriding),3.1.3 Surface finish(Section 14),3.1.4 Cross-sectional shape,3.1.5 Size,3.1.6 Length(Section
7、 13),3.1.7 Class(Section 1),3.1.8 Thermal treatment(Section 6),3.1.9 Hardness(Section 11),3.1.10 Microstructure when desired(Section 7),3.1.11 Report of ladle analysis if desired(Section 9),3.1.12 Straightness(Section 10),3.1.13 ASTM designation A355,and3.1.14 End use,exceptions to the specification
8、,or specialrequirements.4.Process4.1 The steel shall be made by the electric-furnace processonly.5.Discard5.1 Sufficient discard shall be made from each ingot toensure freedom from injurious piping and undue segregation.6.Quenching and Tempering6.1 The bars shall be given a liquid quench followed by
9、 atempering treatment at a temperature not lower than 600C(1112F)to produce a fine spheroidized structure.7.Microstructure7.1 When specified the microstructure resulting from theheat treatment specified in Section 6 shall not show free ferritein amounts exceeding those prescribed in Table 1.Otherper
10、centages of free ferrite may be supplied by agreementbetween the manufacturer and the purchaser.7.2 The amount of free ferrite shall be determined bymetallographic examination under suitable magnification of aspecimen from the bars in the quenched and tempered condi-tion.The number and location of t
11、ests and details of the basisof establishing free ferrite shall be as agreed upon between themanufacturer and the purchaser.8.Decarburization8.1 The maximum depth of total and partial decarburizationof hot-rolled bars and heat-treated bars shall not exceed theamounts prescribed in Table 2.8.2 Center
12、less-ground or turned bars shall be free from totaland partial decarburization.9.Heat Analysis9.1 The steel shall conform to the requirements as to cast orheat(formerly ladle)analysis prescribed in Table 3.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel a
13、nd Related Alloys and is the direct responsibility of SubcommitteeA01.15 on Bars.Current edition approved March 1,2012.Published April 2012.Originallyapproved in 1952.Last previous edition approved in 2006 as A355 89(2006).DOI:10.1520/A0355-89R12.2For referenced ASTM standards,visit the ASTM website
14、,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 10.Straig
15、htness10.1 Unless otherwise specified,all material shall be sup-plied to a maximum straightness tolerance of18in.(3.18 mm)in any 5 ft(1.5 m)but it may not exceed the following:Maximum straightness deviation,in.=18(length in feet)/511.Hardness Test11.1 The hardness of the steel after quenching and te
16、mper-ing shall conform to one of the ranges as specified in Table 4.12.Permissible Variations in Dimensions12.1 The hot-rolled bars shall not vary from the specifieddimensions by more than the amounts prescribed in Specifica-tion A29/A29M.12.2 The diameter of centerless ground bars shall not varyfrom that specified by more than the following:Specified Diameter,in.(mm)PermissibleVariations,Over or Under,in.(mm)Under14(6.35)0.0005(0.013)14to1112(6.35 to 8.73),incl0.001(0.025)Over1132to1932(8.73 to
