A0197_A0197M-00(2006)化铁炉用可锻铸铁.pdf

Designation:A 197/A 197M 00(Reapproved 2006)Standard Specification forCupola Malleable Iron1This standard is issued under the fixed designationA 197/A 197M;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 indicates 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.1.Scope1.1 This specification covers malleable irons for castingsmade by the cupola process.1.2 Without knowledge of casting geometry and processdetails,quantitative relationships cannot be stated between theproperties of the iron in the various locations of a casting andthose of a test bar cast from the same iron.1.3 The values stated in either inch-pound units or SI unitsare to be regarded separately as standard.Within the text,theSI units are shown in brackets.The values stated in eachsystem are not exact equivalents;therefore,each system shallbe used independently of the other.Combining values from thetwo systems may result in nonconformance with the specifi-cation.2.Referenced Documents2.1 ASTM Standards:2A 247 Test Method for Evaluating the Microstructure ofGraphite in Iron CastingsA 644 Terminology Relating to Iron CastingsE 8 Test Methods for Tension Testing of Metallic Materials3.Terminology3.1DefinitionsDefinitions for many terms common toiron castings are found in Terminology A 644.4.Classification4.1 Iron produced for castings ordered under this specifica-tion is classified in a single grade and is qualified by tests onseparately cast test bars.Separately cast test bars shall bepoured from the same lot of iron as the castings they representand shall be heat treated with those castings.5.Ordering Information5.1 The purchase order for castings ordered under thisspecification shall state the specification designation and theyear in which the specification was issued.5.2 Any options or special additions to the basic require-ments of this specification shall be clearly and fully stipulated.6.Chemical Composition6.1 The chemical composition of the iron shall be such as toproduce the mechanical properties required by this specifica-tion.7.Mechanical Requirements7.1 Factors influencing the properties of castings and theirrelationship to those of test specimens and separate testcastings are discussed in Appendix X1.7.2 Tensile Test:7.2.1 Tensile Test Specimens:7.2.1.1 The tensile test specimens shall be cast to the formand dimensions shown in Fig.1 and Fig.2 using the same kindof molding material used for the production castings.7.2.1.2 All test specimens shall be suitably identified withthe designation of the pour period.7.2.1.3 All test specimens shall be heat treated in the sameproduction furnace and for the same cycles as the castings theyrepresent.7.2.2 Tensile Test Method:7.2.2.1 Perform the tensile test on unmachined specimens.7.2.2.2 Gage LengthThe gage length of the standardtensile specimen shall be 2.00 6 0.01 in.50.0 6 0.03 mm.7.2.2.3 Cross-Sectional AreaThe diameter used to com-pute the cross-sectional area shall be the average between thelargest and smallest diameters in that section of the 2-in.50mm gage length having the smallest diameter and shall bemeasured to the nearest 0.001 in.0.02 mm.No cast barhaving a mean diameter less than 0.590 in.15 mm shall beaccepted for test.1This specification is under the jurisdiction of ASTM Committee A04 on IronCastings and is the direct responsibility of Subcommittee A04.02 on Malleable andDuctile Iron Castings.Current edition approved Feb.1,2006.Published February 2006.Originallyapproved in 1936.Last previous edition approved in 2000 as A 197/A 197M 00.2For 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.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.7.2.2.4 Speed of TestingAfter reaching a stress equivalentto approximately half of the anticipated yield stress,the speedof the moving head of the testing machine shall not exceed0.50 in./min 12.5 mm/min through the breaking load.7.2.2.5 Yield StrengthWhile the values for yield point andyield strength are not identical,they are sufficiently close formost applications to be used interchangeably.They shall bedetermined by an approved technique described in Test Meth-ods E 8 or by an equivalent method.If determined as yieldstrength,that stress producing an extension under load of 0.01in.0.25 mm over the 2-in.50 mm gage length(for example,0.5%extension)or an offset of 0.2%shall be taken as theyield stress,which shall be converted to yield strength bydividing by the original cross-sectional area of the gage lengthfound in accordance with 7.2.2.3.It shall be reported to thenearest 100 psi 1 MPa.In referee work,yield strength shall bedetermined at an offset of 0.2%from the stress strain curve.7.2.2.6 Tensile StrengthThe tensile strength shall be themaximum load carried by the specimen during the test dividedby the original cross-sectional area of the gage length,as foundin accordance with 7.2.2.3.It shall be reported to the nearest100 psi 1 MPa.FIG.1 Tension Test SpecimenNOTE1Modifications may be made in the dimensions indicated above for those details of the specimen outside of the gage length as required bytesting procedure and equipment.FIG.2 Alternative Unmachined Tension Test SpecimenA 197/A 197M 00(2006)27.2.2.7 ElongationThe elongation is the increase in gagelength after fracture of a tensile specimen,measured to thenearest 0.01 in.0.25 mm expressed as a percentage of theoriginal gage length.It shall be reported to the nearest 0.5%.7.2.3 Number of Tests and Retests:7.2.3.1 At least three tensile test specimens shall be castfrom a representative ladle of iron from each 4-h pour periodduring which the purchasers castings were poured.7.2.3.2 Only one test specimen need be tested to qualifyeach pour period and heat treatment batch provided therequirements of this specification are met by that test specimen.7.2.3.3 If after testing,a specimen shows evidence of adefect,another tensile test may be made on a companionspecimen.Also,a retest shall be permitted whenever fractureoccurs outside the central 50%of the gage length.7.2.3.4 If the result of a valid test fails to conform to therequirements of this specification,two retests shall be made.Ifeither of the retest fails to meet the specification,all thecastings from the pour period and the heat treat batch repre-sented by these test specimens shall be rejected.7.2.3.5 If the first test results indicate that a reheat treatmentis needed to meet the test requirements,the entire lot ofcastings and the representative test specimens shall be reheattreated together.Testing shall then be repeated in accordancewith 7.2.3.1 through 7.2.3.4.7.2.4 The results of all tests,including retests,shall beposted in permanent records,that shall state any abnormalitiesobserved during the test and in the fractured ends.Such recordsshall be kept for at least one year after production of thecastings and shall be available for examination by the pur-chaser or by his authorized representative.7.2.5 Tensile test results,obtained in accordance with thissection,must conform to the requirements of Table 1.7.2.6 When agreed upon between the manufacturer and thepurchaser,tested specimens or unbroken test bars,or both,shall be saved by the manufacturer for a period of three monthsafter the date of the test report.8.Microstructural Requirements8.1 The microstructure of the malleable iron shall consist oftemper carbon nodules uniformly distributed in a ferritic matrixand shall be free from excessive pearlite,massive carbides,andprimary graphite.8.2 In referee work the metallographic practice recom-mended in Test Method A 247 shall be followed.9.Soundness Requirements9.1 All castings,on visual examination shall be sound andfree from obvious shrinkage and porosity.9.2 If the purchaser requires soundness tests to be per-formed,it shall be so stated in the purchase agreement and themethod and soundness requirements shall be detailed.10.Dimensional Requirements10.1 The castings shall conform to the dimensions given ondrawings furnished by the purchaser,or to the dimensionsestablished by the pattern equipment supplied by the purchaser.11.Workmanship,Finish,and Appearance11.1 The surface of the casting shall be clean,free fromsand,and have a workmanlike finish.12.Identification Marking12.1 When the size of the casting permits,each casting shallbear the identifying mark of the manufacturer and the part orpattern number at a location shown on the covering drawingand if not shown on the drawing,at such a location at thediscretion of the producer that the identification will notinterfere with subsequent processing and service of the casting.12.2 For steam service pressures in excess of 150 psi 1000KPa,the castings shall be marked with the manufacturersname or trademark,numerals to indicate the steam serviceintended,and any other marks that will clearly indicate themaximum service for which the casting is intended.Theseidentifying marks shall be located where they will not interferewith service of the casting.13.Responsibility for Inspection13.1 Unless otherwise specified in the contract or purchaseorder,the manufacturer shall be responsible for carrying out allthe tests and inspections required by this specification,usinghis own or other reliable facilities.The manufacturer shallmaintain complete records of all such test and inspections.Such records shall be available for review by the purchaser.13.2 The manufacturer shall afford the purchasers inspectorall reasonable facilities necessary to satisfy that the material isbeing produced and furnished in accordance with the appli-cable specification.Foundary inspection by the purchaser shallnot interfere unnecessarily with the manufacturers operations.13.3 The purchaser reserves the right to perform any testsand inspections set forth in the specification where such testsand inspections are deemed necessary to assure that compli-ance with this specification is being met.14.Rejection and Rehearing14.1 Any casting or lot of castings failing to comply withthe requirements of this specification may,where possible,bereprocessed,retested,and reinspected.If the tests and inspec-tions on the reprocessed casting(s)show compliance with thisspecification,the castings shall be acceptable;if they do not,they shall be rejected.14.2 Material that fails to conform to the requirements ofthis specification may be rejected.Rejection should be reportedto the producer or supplier promptly and in writing.In case ofdissatisfaction with the results of the test,the producer orsupplier may make claim for a rehearing.15.Certification15.1 When specified in the purchase order or contract,thepurchaser shall be furnished certification that samples repre-senting each lot have been either tested or inspected as directedTABLE 1Tensile Test RequirementsTensile strength,min,psi MPa40 000 275Yield strength,min,psi MPa30 000 200Elongation in 2 in.50 mm,min,%5 5A 197/A 197M 00(2006)3in this specification and the requirements have been met.Whenspecified in the purchase order or contract,a report of the testresults shall be furnished.16.Packaging and Package Marking16.1 Unless otherwise stated in the contract or order,thecleaning,preservation,and packing of casting for shipmentshall be in accordance with the manufacturers commercialpractice.Packaging and package marking shall also be ad-equate to identify the contents and to ensure acceptance andsafe delivery by the carrier for the mode of transportationemployed.APPENDIX(Nonmandatory Information)X1.MECHANICAL PROPERTIES OF CASTINGSX1.1 The mechanical properties of malleable iron castingsare influenced by a number of factors,that include the coolingrate during solidification,chemical composition,the heattreatment,the design of the casting,section thickness,and thelocation and effectiveness of gates,risers,and chills.X1.2Because of the complexity of these factors in influ-encing the properties of the final product,no precise quantita-tive relationship can be stated between the properties of theiron in various locations of a given casting or between theproperties of a casting and those of a test specimen cast fromthe same iron.When such a relationship is important and mustbe known for a specific application,it may be determined byappropriate experimentation.X1.3The specimen specified in 7.2.1.1 as the standardtensile test bar for malleable iron has a58-in.16 mm diametertest section that reasonably represents a typical section of thegeneral run of malleable iron castings.Furthermore,the initialfreezing and malleable irons as homogeneous white iron,together with the heat treatment that is inherent in the manu-facture of malleable iron,tends to reduce the section-sensitivityeffect.Therefore,where experimentation into precise proper-ties within a given casting would be unfeasible,this standardtest bar,made like any typical casting,should provide apractical approximation of the properties that can be expectedin any average sound malleable iron castings.When thenumber of standard test bars to determine specification com-pliance is insufficient,the manufacturer may wish to seekpurchaser approval by comparing tension test results from thecasting in question with those of two other castings having thesame design and test bar location and from which acceptablestandard bar results were obtained.X1.4 If malleable iron castings are welded,the microstruc-ture of the iron is markedly affected,particularly in theheat-affected zone.Since this may adversely affect the proper-ties of the casting,the welding of malleable iron castingsshould be done under strict metallurgical control,followed byappropriate post-weld heat treatment,to minimize the substan-tial reductions in ductility,impact resistance,and machinabilitythat could result,particularly in the vicinity of the weldment.Nevertheless,it is generally considered inadvisable to joincastings to similar castings or to other materials,by fusionwelding out in the field,or in manufactured assemblies,without fully testing the entire completed part.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.Users of this standard are expressly advised that determination of the validity of any such patent rights,and the riskof 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 withdrawn.Your comments are invited