1、Designation:A 730 93(Reapproved 1999)Standard Specification forForgings,Carbon and Alloy Steel,for Railway Use1This standard is issued under the fixed designation A 730;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last
2、 revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This specification covers eight grades of untreated andheat-treated carbon steel forgings and six grades of heat-treatedalloy
3、steel forgings for railway use.NOTE1It is recommended,when semi-finished steel is desired toprocess these forgings,that the latest issue of ASTM Specification A 711,for Carbon and Alloy Steel Blooms,Billets,and Slabs for Forging,2beused.This will enable the forger to select semi-finished material of
4、 suchchemistry as he desires.NOTE2Railway axles are covered by Specification A 21.1.2 The grades of carbon steel forgings and the purposes forwhich they are frequently used are as follows,the choicedepending on design and stress or service to be imposed:1.2.1 Grade A is untreated and is mostly used
5、for dropforgings and parts of minor importance,and those which are tobe case hardened.1.2.2 Grade B is untreated and is used for a general groupof miscellaneous ordinary forgings where heat treatment is notdeemed necessary.1.2.3 Grade C is annealed,normalized,or normalized andtempered.1.2.4 Grade D
6、is annealed,normalized,or normalized andtempered.1.2.5 Grade E is normalized and tempered.1.2.6 Grade F is double normalized and tempered.1.2.7 Grade G is quenched and tempered.1.2.8 Grade H is normalized,quenched,and tempered.1.2.9 Grades E,F,G,and H forgings are used in high-dutyservice on locomot
7、ives,cars,and other equipment.1.3 The grades of alloy steel forgings are as follows:1.3.1 Grades I,J,and K are normalized and tempered.1.3.2 Grades L,M,and N are normalized,quenched,andtempered,and are used in heavy-duty service on locomotives,cars,and special equipment.NOTE3The forgings described a
8、bove were formerly designated asfollows:Current GradeFormer Designation and GradeAA 236,ABA 236,BCA 236,CDA 236,DEA 236,EFA 236,FGA 236,GHA 236,HIA 238,AJA 238,BKA 238,CLA 238,DMA 238,ENA 238,F1.4 Supplementary Requirements(Sections S1 to S5)of anoptional nature are provided.These shall apply only w
9、henspecified by the purchaser.1.5 The values stated in inch-pound units are to be regardedas the standard.2.Referenced Documents2.1 ASTM Standards:A 21 Specification for Carbon Steel Axles,Non-Heat-Treated and Heat-Treated,for Railway Use2A 370 Test Methods and Definitions for Mechanical Testingof S
10、teel Products3A 711 Specification for Steel Forging Stock4E 112 Test Methods for Determining the Average GrainSize5E 381 Method of Macroetch Testing Steel Bars,Billets,Blooms,and Forgings53.Ordering Information3.1 The purchaser shall specify in the inquiry,contract,andorder the grade of steel desire
11、d,and any restrictive modifica-tions of this specification.3.2 Supplementary requirements are provided and shallapply only when specified in the purchase order.4.Manufacture4.1 Melting ProcessThe steel shall be made by one ormore of the following processes:open-hearth,basic-oxygen,orelectric-furnace
12、.1This specification is under the jurisdiction of ASTM Committee A-1 on Steel,Stainless Steel,and Related Alloys and is the direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved Dec.15,1993.Published February 1994.Originallypublished as A 73076 to replace
13、 A 236 and A 238.Last previous editionA 73081(1988).2Annual Book of ASTM Standards,Vol 01.04.3Annual Book of ASTM Standards,Vol 01.03.4Annual Book of ASTM Standards,Vol 01.05.5Annual Book of ASTM Standards,Vol 03.01.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA
14、 19428-2959,United States.4.2 DiscardSufficient discard shall be made to assurefreedom from piping and undue segregation.4.3 Forging PracticeThe forgings may be made directfrom the ingot or from blooms.The total reduction from ingotor strand cast bloom to forging shall not be less than 3 to 1,unless
15、 otherwise specified.4.4 Cooling and Heating:4.4.1 After carbon steel blooms are produced,they shall beallowed to cool uniformly and shall not be subject to contactwith water or drafts.4.4.2 After alloy steel blooms are produced,they shall becooled in closed containers,hoods,or furnaces.4.4.3 Blooms
16、 shall be reheated for forging in a manner thatwill prevent internal bursts and overheating.4.4.4 Forgings(Grades C through N)shall be slow cooled inclosed containers,covered conveyors,or hoods.If forgings(Grades C through N)are heat treated directly from forging,they shall be slow cooled following the final heat treatment.4.4.5 Forgings(Grades C through N)that are heat treateddirectly from forging(1)shall be cooled below the transfor-mation temperature or to approximately 1000F(538C)be-fore any
