1、Designation: A842 10Standard Specification forCompacted Graphite Iron Castings1This standard is issued under the fixed designation A842; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenth
2、eses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers castings made of compactedgraphite iron, which is described as cast iron with the graphitein compacted (vermiform) shapes and
3、essentially free of flakegraphite.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.2.1 ExceptionThe inch-pound units in Figs. 1-3 arestandard. SI units are added for information only.1.3 No precise quantitative relationship
4、 can be stated be-tween the properties of iron in the various locations of the samecasting and those of a test bar cast from the same iron (seeAppendix X1).2. Referenced Documents2.1 ASTM Standards:2A247 Test Method for Evaluating the Microstructure ofGraphite in Iron CastingsE8/E8M Test Methods for
5、 Tension Testing of MetallicMaterials2.2 Federal Standard:3Federal Standard No. 123 Marking for Shipment (CivilAgencies)2.3 American National Standard:4MIL-STD-129 Marking for Shipment and Storage3. Ordering Information3.1 Orders for material to this specification shall include thefollowing informat
6、ion:3.1.1 ASTM designation and year of issue,3.1.2 Grade of compacted graphite iron required as identi-fied in Table 1,3.1.3 Special properties if required, (see 4.1 and 10.1),3.1.4 If samples other than those identified in Section 9 arerequired,3.1.5 Certification if so designated by the purchaser,
7、 and3.1.6 Special preparation for delivery if required.4. Chemical Composition4.1 It is the intent of this specification to subordinatechemical composition to mechanical properties; however, anychemical requirement may be specified by agreement betweenthe manufacturer and the purchaser.5. Requiremen
8、ts5.1 Compacted graphite cast iron shall be examined metal-lographically for the acceptable graphite formation.5.2 The metallographic examination shall be performed on acasting, a separately cast test coupon, as shown in Fig. 1 or ona test lug from a casting. The test coupon or casting lug shallrepr
9、esent the last metal from the treated batch. The casting lugdimension and location will be agreed on by manufacturer andpurchaser.5.3 When castings are produced to this specification bytreating the iron in the mold for graphite form control, themanufacturer may use separately cast test coupons or cu
10、t testspecimens from castings to qualify conformance of the micro-structure requirements. When separately cast test coupons areused, the test coupons shall have a chemical compositionrepresentative of that in the castings, produced from that ironpoured, and having a cooling rate equivalent to that o
11、btainedthrough use of test molds as shown in Figs. 1-3. The size of thecast coupon representing the castings shall be the option of thepurchaser. In case no option is expressed, the manufacturershall make the choice. When test specimens are to be takenfrom a casting, the location shall be agreed on
12、by the purchaserand the manufacturer and documented on the casting drawing.It is the manufacturers required responsibility to maintainadequate controls and documentation to assure the customerthat test specimen microstructures are representative of micro-structure in the castings shipped.5.4 The acc
13、eptable graphite formation in the microstructureof the test coupon or casting lug shall contain 80 % minimumType IV graphite (see Plate 1, Graphite Form Types of Test1This specification is under the jurisdiction of ASTM Committee A04 on IronCastings and is the direct responsibility of Subcommittee A
14、04.02 on Malleable andDuctile Iron Castings.Current edition approved Dec. 1, 2010. Published January 2011. Originallyapproved in 1985. Last previous edition approved in 2009 as A842 - 85 (2009).DOI: 10.1520/A0842-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM
15、 Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps
16、.dla.mil.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Method A247). The percentage graphite can be arri
17、ved at byusing the manual particle count, semiautomatic, or automaticimage analysis methods. Whichever method is used, theprocedure should be agreed on between the manufacturer andthe purchaser.5.5 Unless otherwise specified, the matrix microstructure ofcastings covered by this specification shall b
18、e substantially freeof primary cementite.6. Tensile Requirements6.1 The iron as represented by the test specimens shallconform to the requirements for tensile properties, as identifiedin Table 1.6.2 Tensile properties shall be determined using the test bardescribed in 7.1 or one of the test coupons
19、described in 7.2except as provided in 10.4.6.3 The yield strength presented in Table 1 shall be deter-mined at 0.2 % offset by the offset method as described in TestMethods E8/E8M. Other methods may be used by mutualagreement between manufacturer and purchaser.7. Cast Test Bars7.1 Test bars shall be
20、 separate castings poured from thesame iron as the castings they represent. The 30-mm diametercylindrical test bar shall be used as described in Table 2 andshown in Fig. 4.7.2 Test coupons may also be cast to the size and shape ofthe keel block or modified keel block shown in Fig. 2 and Fig.3, respe
21、ctively.7.3 Test bars and test coupons shall be cast in dried, baked,or chemically bonded molds consisting of an aggregate ofsilica sand with the appropriate binders. All molds shall have athickness of sand adjacent to the test piece equal to or greaterthan the thickness of the piece.7.4 The test ba
22、rs or test coupons shall be poured from thesame ladle or heat of iron as the castings they represent.7.5 Test bars and test coupons shall be subjected to the samethermal treatment as the castings they represent.8. Tension Test Specimen8.1 The standard round tension test specimen with 50-mmgage lengt
23、h described in Test Methods E8/E8M shall be used.9. Workmanship, Finish, and Appearance9.1 The surface of the casting shall be inspected visually forsurface discontinuities such as cracks, hot tears, adhering sandor scale, cold shuts, and gas holes. Surface discontinuities shallmeet visual acceptanc
24、e standards mutually agreed on betweenthe purchaser and the supplier.9.2 No repairing by plugging or welding of any kind shallbe permitted unless written permission is granted by thepurchaser.FIG. 1 Test Coupon for Microscopical Examination of Compacted Graphite IronNOTEThe length of the keel block
25、shall be 6 in. (152 mm).Metric Equivalentsin. mm in. mm12 12.7 112 38.11 25.4 212 63.5FIG. 2 Keel BlockA842 10210. Number of Tests and Retests10.1 The manufacturer shall cast a minimum of three testbars for each lot of castings intended to conform to thisspecification. The manufacturer shall perform
26、 the specifiedtests. If any test specimen shows defective or impropermachining, or obvious lack of continuity of metal, it may bediscarded and replaced by another specimen from another testbar from the same lot. Only one bar needs to be tested if itsresults conform to the property requirements of th
27、is specifica-tion.10.2 If after testing, a test specimen shows evidence of adefect, the results of the test may be invalidated and anothertest may be performed on a specimen from the same lot.10.3 If the results of a valid test fail to conform to therequirements of this specification, two retests sh
28、all be made. Ifeither retest fails to meet the specification requirements, thecastings represented by these test specimens shall be rejected.A valid test is one wherein the specimen has been properlyprepared and appears to be sound and on which the approvedtest procedure has been followed.10.4 If su
29、fficient separately cast test pieces are not available,the manufacturer shall have the option of removing a testspecimen from a location of a representative casting as agreedupon between the manufacturer and purchaser.10.5 If the first test results indicate that a thermal treatmentis needed to meet
30、the test requirements, the entire lot ofcastings and the representative test specimens shall be ther-mally treated together. Testing shall proceed in accordancewith 10.1-10.4.11. Inspection11.1 Unless otherwise specified in the contract or purchaseorder, the manufacturer shall be responsible for car
31、rying out allFIG. 3 Mold for Modified Keel BlockTABLE 1 Tensile RequirementsGradeA250Grade300Grade350Grade400GradeB450Tensile strength, min,MPa250 300 350 400 450Yield strength, min,MPa175 210 245 280 315Elongation in 50 mm,min, %3.0 1.5 1.0 1.0 1.0AThe 250 grade is a ferritic grade. Heat treatment
32、to attain required mechanicalproperties and microstructure shall be the option of the manufacturer.BThe 450 grade is a pearlitic grade usually produced without heat treatmentwith addition of certain alloys to promote pearlite as a major part of the matrix.FIG. 4 Design and Dimensions for Mold for Se
33、parately CastCylindrical Test BarsTABLE 2 Diameter and Length of Cast Test BarTest Bar NominalAs Cast Diameter, mm Length, mmMinimum Maximum Minimum MaximumB 30 29 31 150 230A842 103the tests and inspections required by this specification, usinghis own or other reliable facilities, and he shall main
34、taincomplete records of all such tests and inspections. Such recordsshall be available for review by the purchaser.11.2 The purchaser reserves the right to perform any of theinspections set forth in the specification where such inspectionsare deemed necessary to assure that supplies and servicesconf
35、orm to the prescribed requirements.12. Certification12.1 When specified in the purchase order or contract, themanufacturers or suppliers certification shall be furnished tothe purchaser stating that samples representing each lot havebeen manufactured, tested, and inspected in accordance withthis spe
36、cification and the requirements have been met. Whenspecified in the purchase order or contract, a report of the testresults shall be furnished.13. Product Marking13.1 When the size of the casting permits, each casting shallbear the cast date, the identifying mark of the manufacturer,and the part or
37、pattern number at a location shown on thecovering drawing and, if not shown on the drawing, thelocation should be at the discretion of the producer.14. Packaging and Package Marking14.1 Unless otherwise stated in the contract or order, thecleaning, preservation, and packing of castings for shipments
38、hall be in accordance with the manufacturers commercialpractice. Packaging and marking shall also be adequate toidentify the contents and to ensure acceptance and safe deliveryby the carrier for the mode of transportation employed.14.2 U.S. Government ProcurementWhen specified in thecontract or purc
39、hase order, marking for shipment shall be inaccordance with the requirements of Federal Standard No. 123for civil agencies and MIL-STD-129 for military activities.SUPPLEMENTARY REQUIREMENTSS1. When specified in the contract or purchase order,castings shall meet special requirements as to hardness, c
40、hemi-cal composition, microstructure, pressure tightness, radio-graphic soundness, magnetic particle inspection dimensions,and surface finish.APPENDIX(Nonmandatory Information)X1. MECHANICAL PROPERTIES OF CASTINGSX1.1 The mechanical properties of iron castings are influ-enced by the cooling rate dur
41、ing and after solidification, bychemical composition (particularly carbon equivalent), by thedesign of the casting, by the design and nature of the mold, bygraphite form, by the location and effectiveness of gates andrisers, and by certain other factors. In compacted graphite castiron, the proportio
42、ns of nodular form and compacted formgraphite can vary in varying sections due to the above factors.X1.2 The cooling rate in the mold and, therefore, theproperties developed in any particular section are influenced bythe presence of cores, chills, and chaplets; changes in sectionthickness; and the e
43、xistence of bosses, projections, and inter-sections, such as junctions of ribs and bosses. Because of thecomplexity of the interactions of these factors, no precisequantitative relationship can be stated between the propertiesof the iron in various locations of the same casting or betweenthe propert
44、ies of a casting and those of a test specimen castfrom the same iron. When such a relationship is important andmust be known for a specific application, it can be determinedby appropriate experimentation.X1.3 When reliable information is unavailable on therelationship between properties in a casting
45、 and those in aseparately cast test specimen, and where experimentationwould be infeasible, the size of the test casting should be soselected as to approximate the thickness of the main orcontrolling section of the casting.X1.4 Table X1.1 is a typical hardness range for the gradesof compacted graphi
46、te cast iron in this specification. Thechemical composition of the base iron used to produce com-pacted graphite cast iron can result in the hardness rangemoving to either side of the given range.TABLE X1.1 Compacted Graphite Cast Iron Hardness RangeGrade Hardness BIDA250 179 max (4.50 min)300 14320
47、7 (5.04.2)350 163229 (4.74.0)400 197255 (4.33.8)450 207269 (4.23.7)ABrinell impression diameter (BID) is the diameter in millimetres of theimpression of a 10-mm ball at a 3000-kg load.A842 104ASTM International takes no position respecting the validity of any patent rights asserted in connection wit
48、h 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 techn
49、ical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by
