1、Designation:A291/A291M16aStandard Specification forSteel Forgings,Carbon and Alloy,for Pinions,Gears andShafts for Reduction Gears1This standard is issued under the fixed designation A291/A291M;the number immediately following the designation indicates the yearof original adoption or,in the case of
2、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.1.Scope*1.1 This specification covers normalized and tempered car-bon steel and quenched and tempered alloy stee
3、l forgings forpinions,gears,and shafts.1.2 Several grades of steel are covered as follows:1.2.1 Grade 1,Class A,is normalized and tempered carbonsteel.1.2.2 Grade 2,Class B,Grade 3,Class C,Grade 3A,ClassD,Grades 4 to 7,Classes E,F,G,and H,Grade 8,Class I,andGrade 9,Class J,are liquid quenched and te
4、mpered alloy steel.1.3 All grades and classes are considered weldable underproper conditions.Welding technique is of fundamental impor-tance and it is presupposed that welding procedure andinspection shall be in accordance with approved methods forthe class of material used.1.4 The values stated in
5、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.1.5 This standar
6、d 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Sta
7、ndards:2A275/A275M Practice for Magnetic Particle Examination ofSteel ForgingsA388/A388M Practice for Ultrasonic Examination of SteelForgingsA788/A788M Specification for Steel Forgings,General Re-quirements3.Terminology3.1 Definitions:3.1.1 gearsrings,disks,cylinders or rectangular bars hav-ing gear
8、 teeth.3.1.2 pinionscircular cross section forgings of multiplediameter with gear teeth on one or more diameters.3.1.3 shaftscircular cross section forgings of one or morediameters which do not have integral gear teeth.4.Ordering Information4.1 Instructions for purchasing forgings to this specificat
9、ionshould be in accordance with Specification A788/A788M.Inaddition,a detailed drawing,sketch,or written description ofthe forging should be included with the inquiry or order.4.2 Supplementary requirements are provided and shallapply only when specified in the purchase order.5.Heat Treatment5.1 Pre
10、liminary Heat Treatment:5.1.1 The forgings shall be given such preliminary heattreatment as is proper for the design and composition.Theforgings shall be heated to a suitable temperature for asufficient length of time for austenitization and shall be suitablycooled to bring about complete transforma
11、tion.5.1.2 Forgings may be immediately treated for mechanicalproperties after preliminary heat treatment or may be roughturned prior to treatment for mechanical properties.5.2 Heat Treatment for Mechanical PropertiesThe forg-ing shall be reheated to a temperature above the upper criticaltemperature
12、and held a sufficient length of time for completeaustenitization.Grade 1 shall be air cooled while Grades 2through 9 shall be liquid quenched.5.3 TemperingThe forgings shall be tempered to developthe specified properties.Minimum tempering temperaturesshall be as follows:1This specification is under
13、the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved Dec.1,2016.Published December 2016.Originallyapproved in 1946.Last previous edition approved in 2016 as A29
14、1/A291M 16.DOI:10.1520/A0291_A0291M-16A.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.*A Summary of Changes sect
15、ion appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 Minimum Tempering TemperatureGradeClassFC1 and 2A and B11506203,3A,and 4C,D,and E10755805,6,7F,G,and H10505658I11005959J1000540The charge shall be cool
16、ed under uniform conditions in thefurnace at a maximum rate of 100 F 55 C per h to 600 F315 C.5.4 Stress ReliefIf the manufacturer elects to heat treat formechanical properties prior to machining,the forgings shall bestress relieved after machining(see 5.5)at a temperature that is50 to 100 F 30 to 55 C below the last previous temperingtemperature but in no case below 1000 F 540 C.Theforgings shall be cooled under uniform conditions in thefurnace at a maximum rate of 100 F 55 C h to 600 F315 C.5.
