1、Designation:A 48/A 48M-00Standard Specification forGray Iron CastingsThis standard is issued under the fixed designation A 48/A 48M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number in parentheses ind
2、icates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.This specification replaces Federal SpecificationQ0-652.1.Scope3.1.1 Definitions for many te
3、rms common to gray iron1.1 This specification covers gray iron castings intended forcastings are found in Terminology A 644.general engineering use where tensile strength is a major4.Classificationconsideration.Castings are classified on the basis of the tensilestrength of the iron in separately cas
4、t test bars.4.1 Castings ordered and produced in accordance with this1.1.1 This specification subordinates chemical compositionspecification are classified into a number of grades based on theto tensile strength.properties of separately cast test bars(Table 1).Each class is1.2 Castings produced to t
5、his specification are graded on thedesignated by a number followed by a letter.The numberbasis of minimum tensile strength obtained in special testindicates the minimum tensile strength of the separately castcoupons designed to standardize cooling rate.The tensiletest bar,and the letter indicates th
6、e size of the test bar.strength developed in certain casting sections may vary fromExamples of proper designations are as follows:test coupon values(see X1.2).Gray Iron Castings,ASTM Specification A 48,Class 30B.1.3 The values stated in either inch-pound units or SI unitsGray Iron Castings,ASTM Spec
7、ification A 48.Class 40C.are to be regarded separately as standard.Within the text,the5.Ordering InformationSI units are shown in brackets.The values stated in eachsystem are not exact equivalents;therefore,each system shall5.1 Orders for material to this specification shall include thebe used indep
8、endently of the other.Combining values from thefollowing information:two systems may result in nonconformance with the specifi-5.1.1 ASTM designation number and year of issue,cation.5.1.2 Class of iron required(see 4.1 and Table 1),5.1.3 The size of the separately cast test bar(letter2.Referenced Do
9、cumentsclassification-A,B,C,or S)that best represents the thickness2.1 ASTM Standards:of the controlling section of the casting(see Table 2),A 644 Terminology Relating to Iron Castings25.1.4 The tension test specimen(B or C)to be machinedE8 Test Methods for Tension Testing of Metallic Materials3from
10、 test bar C(see 13.3,Table 3,and Fig.1).2.2 Military Standard:5.1.5 The tension test specimen to be machined from testMIL-STD-129 Marking for Shipment and Storagebar S(see 13.4.Table 3,and Fig.1).2.3 Federal Standard:5.1.6 Lot size(see Section 10),Federal Standard No.123 Marking for Shipment(Civil5.
11、1.7 Special requirements(see Section 6).Agencies)45.1.8 Saving tested specimens or unbroken test bars(see15.1),and3.Terminology5.1.9 Special preparation for delivery(see Section 19).3.1 Definitions:6.Special Requirements6.1 When agreed upon in writing between the manufacturerThis specification is un
12、der the jurisdiction of ASTM Committee A04 on Ironand the purchaser,it may be necessary for the castings to meetCastings and is the direct responsibility of Subcommittee A04.01 on Gray Ironspecial requirements as to hardness,chemical composition,Castings.microstructure,pressure tightness,radiographi
13、c soundness,Current edition approved May 10,2000.Published June 2000.Originallydimensions,surface finish,etc.published as A 48-05.Last previous edition A 48-94a.2 Annual Book of ASTM Standards,Vol 01.02.3 Annual Book of ASTM Standards,Vol 03.01.Available from Standardization Documents Order Desk,Bld
14、g.4 Section D,700Robbins Ave.Philadelphia,PA 19111-5094.Attn:NPODS.Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959.United States.COPYRIGHT ASTM InternationalLicensed by Information Handling Services46)A48/A48MTABLE 1 Requirements for Tensile Strength of Gray Cast Ironsthe dimens
15、ions predicted by the pattern equipment supplied byin Separately Cast Test Barsthe purchaser.ClassTensile Strength,Nominal Test Barmin,ksi MPaDiameter,in.mm9.Workmanship and FinishNo.20 A20(138)0.88(22.4)9.1 The surface of the casting shall be free of adhering sand,No.20 B1.2(30.5)scale,cracks,and h
16、ot tears,as determined by visual examina-No.20C2.0(50.8No.20 SBars SAtion.9.2 No repairing by plugging or welding of any kind shallNo.25 A25(172)0.88(22.4)be permitted unless written permission is granted by theNo.25 B1.2(30.5)No.25 C2.0(50.8)purchaser.No.25 SBars S410.SamplingNo.30 A30(207)0.88(22.
17、4)10.1 A lot shall consist of one of the following:N0.30B12(30.5No.30 C2.0(50.8)10.1.1 All the metal poured from a single heating in a batchNo.30 SBars S4type melting furnace.10.1.2 All the metal from two or more batch type meltingNo.35 A35(241)0.88(22.4)No.35 B1.2(30.5)furnaces poured into a single
18、 ladle or a single casting.No.35 C2.0(50.8)10.1.3 All the metal poured from a continuous meltingNo.35 SBars S4furnace for a given period of time between changes in charge,No.40A40(276)0.88(22.4)processing conditions,or aim-for chemistry or 4 h,whicheverNo.40 B1.2(30.5)is the shorter period.No.40 C2.
19、0(50.8)10.1.3.1 The purchaser may agree to extend the 4-h timeNo.40SBars SAperiod to 8 h if the manufacturer can demonstrate sufficientNo.45A45(310)0.88(22.4)process control to warrant such an extension.No.45B1.2(30.5)No.45 C2.0(50.8)11.Cast Test BarsNo.45 SBars S411.1 Test bars shall be separate ca
20、stings poured from theNo.50 A50(345)0.88(22.4)same lot as the castings they represent and shall have dimen-No.50 B12(30.5)sions as shown in Table 3.Allowance may be made forNo,50 C2.0(50.8)reasonable pattern draft within the tolerances shown in Table 3.No.50 SBars SATest bars A,B,and C are all stand
21、ard test bars in the form ofN0.55A55(379)0.88(22.4)simple cylinders.Test bar S is special and is intended for useNo.55 B1.2(30.5)where the standard bars are not satisfactory.N0.55C2.0(50.8)No.55 SBars S411.2 The test bars shall be cast in dried,baked,or chemi-cally bonded molds made mainly of an agg
22、regate of siliceousNo.60A60(414)0.88(22.4)No.60 B1.2(30.5)sand with appropriate binders.The average grain size of theNo.60 C2.050.8)sand shall approximate that of the sand in which the castingsNo.60 SBars SAare poured.Molds for the test bars shall be approximately atAAll dimensions of test bar S sha
23、ll be as agreed upon between the manufacturerroom temperature when poured.More than one test bar may beand the purchaser.cast in a single mold,but each bar in the mold shall besurrounded by a thickness of sand which is not less than theTABLE 2 Separately Cast Test Bars for Use When a Specificdiamete
24、r of the bar.A suitable design for a mold is shown inCorrelation Has Not Been Established Between the Test Bar andthe CastingFig.2.Thickness of the Wall of the ControllingNorE 1-The intent of these provisions is as follows:to prohibit theSection of the Casting,in.mmTest Barcasting of test bars in mo
25、lds of metal,graphite,zircon,light-weightUnder 0.25 under 6aggregates,or other materials which would significantly affect the tensile0.25t00.506to13Astrength of the iron;to prohibit control of tensile strength of the test bars0.51to1.0013to25by manipulation of the grain size of the sand;and to prohi
26、bit the casting1.01to226to51】of test bars in molds preheated substantially above room temperatureOver 2 over 5111.3 Test bars that are intended to represent castings that arecooled in the mold to less than 900F 480C.before7.Tensile Requirementsshakeout,shall be cooled in their molds to a temperature
27、 lessthan 900F 480C.They then may be cooled in still air to7.1 Test bars representing castings conforming to this speci-room temperature.fication shall meet the requirements for tensile strength as11.4 Test bars that are intended to represent castings that aredescribed in Table 1.hotter than 900F 48
28、0C,when shaken out of their molds,shall be cooled as described in 11.3 or(by agreement between8.Dimensional Requirementsthe manufacturer and the purchaser)may be shaken out of their8.1 The castings shall conform to the dimensions or draw-molds at approximately the same temperature as the castingsing
29、s furnished by the purchaser,or,if there are no drawings,tothey represent.2COPYRIGHT ASTM InternationalLicensed by Information Handling Services4A48/A48M19.2 U.S.Government Procurement-When specified in the20.Keywordscontract or purchase order,marking for shipment shall be inaccordance with the requ
30、irements of Fed.Std.No.123 for civil20.1 gray iron castingsagencies and MIL-STD-129 for military activities.APPENDIX(Nonmandatory Information)XI.MECHANICAL PROPERTIES OF CASTINGSX1.1 The mechanical properties of iron castings are influ-characterized by excellent machinability,high damping capac-ence
31、d by the cooling rate during and after solidification,byity,low modulus of elasticity,and comparative ease of manu-chemical composition(particularly carbon equivalent),by thefacture.design of the casting,by the design and nature of the mold,byX1.3.1 Castings in Classes 40,45,50,55 and 60 are usually
32、the location and effectiveness of gates and risers,and by certainmore difficult to machine,have lower damping capacity and aother factors.higher modulus of elasticity,and are more difficult to manu-X1.2 The cooling rate in the mold and,hence,the proper-facture.ties developed in any particular sectio
33、n are influenced by thepresence of cores:chills and chaplets;changes in sectionX1.4 When reliable information is unavailable on thethickness;and the existence of bosses,projections,and inter-relationship between properties in a casting and those in asections,such as junctions of ribs and bosses.Beca
34、use of theseparately cast test specimen,and where experimentationcomplexity of the interactions of these factors,no precisewould be unfeasible,the size of the test casting should be soquantitative relationship can be stated between the propertiesselected as to approximate the thickness of the main o
35、rof the iron in various locations of the same casting or betweencontrolling section of the casting.the properties of a casting and those of a test specimen castfrom the same iron.When such a relationship is important andX1.5 If iron castings are welded(see 9.2),the microstruc-must be known for a spe
36、cification application,it may beture of the iron is usually altered,particularly in the vicinity ofdetermined by appropriate experimentation.the weldment.Therefore,the properties of the casting may beadversely affected by welding.Where practical,appropriateX1.3 Gray iron castings in Classes 20,25,30
37、 and 35 arepost weld heat treatment may reduce this effect of welding.The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connectionwith any item mentioned in this standard.Users of this standard are expressly advised that determi
38、nation of the validity of any suchpatent rights,and the risk of infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised,either reapproved or withd
39、rawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee,which you may attend.If you feel that your comments have not
40、 received a fair hearing you should make yourviews known to the ASTM Committee on Standards,at the address shown below.This standard is copyrighted by ASTM.100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.Individual reprints(single or multiple copies)of this standard may be obtained by contacting ASTM at the above address or at610-832-9585(phone),610-832-9555(fax),or serviceastm.org(e-mail);or through the ASTM website(www.astm.org).5COPYRIGHT ASTM InternationalLicensed by Information Handling Services
