1、Designation: A 842 85 (Reapproved 2004)Standard Specification forCompacted Graphite Iron Castings1This standard is issued under the fixed designation A 842; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 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 castings made of compactedgraphite iron, which is described as cast iron with the graphitein compacted (v
3、ermiform) shapes and essentially free of flakegraphite.1.2 The values stated in SI units are to be considered as thestandard.1.3 No precise quantitative relationship 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 i
4、ron (seeAppendix X1).2. Referenced Documents2.1 ASTM Standards:2A 247 Test Method for Evaluating the Microstructure ofGraphite in Iron CastingsE8M Test Methods for Tension Testing of Metallic Mate-rials (Metric)2.2 Federal Standard:3Fed. Std. No. 123 Marking for Shipment (Civil Agencies)2.3 American
5、 National Standard:4MIL-STD-129 Marking for Shipment and Storage3. Ordering Information3.1 Orders for material to this specification shall include thefollowing information: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
6、 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, and3.1.6 Special preparation for delivery if required.4. Chemical Composition4.1 It is the intent of this specification to subordin
7、atechemical composition to mechanical properties; however, anychemical requirement may be specified by agreement betweenthe manufacturer and the purchaser.5. Microstructure Requirements Microstructure Requirements5.1 Compacted graphite cast iron shall be examined metal-lographically for the acceptab
8、le 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 shallrepresent the last metal from the treated batch. The casting lugdimension and location will b
9、e 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 cut testspecimens from castings to qualify conformance of the micro-structure requirements.
10、 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 obtainedthrough use of test molds as shown in Figs. 1-4. The size of thecast coupon repres
11、enting 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 by the purchaserand the manufacturer and documented on the casting drawing.1This specific
12、ation 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 May 1, 2004. Published May 2004. Originallyapproved in 1985. Last previous edition approved in 1997 as A 842 -
13、85 (1997).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.3Available from Standardization Documents Order Des
14、k, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.TABLE 1 Tensile RequirementsGradeA250Grade300Grade350Grade400GradeB450Tensile strength, min,MPa250 300 350 400 45
15、0Yield 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 to attain required mechanicalproperties and microstructure shall be the option of the manufacturer.BThe 450 grade is a pearlitic grade usually produced without h
16、eat treatmentwith addition of certain alloys to promote pearlite as a major part of the matrix.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.It is the manufacturers required responsibility to maintainadequate controls and documenta
17、tion to assure the customerthat test specimen microstructures are representative of micro-structure in the castings shipped.5.4 The acceptable graphite formation in the microstructureof the test coupon or casting lug shall contain 80 % minimumType IV graphite (see Plate 1, Graphite Form Types of Tes
18、tMethod A 247). The percentage graphite can be arrived 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 microstructu
19、re ofcastings covered by this specification shall be 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 The yield strength presented in Table 1 shall be d
20、eter-mined at 0.2 % offset by the offset method as described in TestMethods E8M. Other methods may be used by mutualagreement between manufacturer and purchaser.7. Cast Test Bars7.1 Test bars shall be separate castings poured from thesame iron as the castings they represent. The 30-mm diametercylind
21、rical test bar shall be used as described in Table 2 andshown in Fig. 2.7.2 Test coupons may also be cast to the size and shape ofthe keel block or modified keel block shown in Fig. 3 and Fig.4, respectively.7.3 Test bars and test coupons shall be cast in dried, baked,or chemically bonded molds cons
22、isting of an aggregate ofsilica sand with the appropriate binders. All molds shall have aFIG. 1 Test Coupon for Microscopical Examination of Compacted Graphite IronFIG. 2 Design and Dimensions for Mold for Separately CastCylindrical Test BarsNOTEThe length of the keel block shall be 6 in. (152 mm).M
23、etric Equivalentsin. mm in. mm12 12.7 112 38.11 25.4 212 63.5FIG. 3 Keel BlockA 842 85 (2004)2thickness of sand adjacent to the test piece equal to or greaterthan the thickness of the piece.7.4 The test bars or test coupons shall be poured from thesame ladle or heat of iron as the castings they repr
24、esent.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 length described in Test Methods E8Mshall be used.9. Workmanship, Finish, and Appearance9.1 The surf
25、ace 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 acceptance standards mutually agreed on betweenthe purchaser and the supplier.9.2 No repairing by plugging o
26、r welding of any kind shallbe permitted unless written permission is granted by thepurchaser.10. 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 make the specified tests.
27、If any test specimen shows defective or improper machining,or obvious lack of continuity of metal, it may be discarded andreplaced by another specimen from another test bar from thesame lot. Only one bar need be tested if its results conform tothe property requirements of this specification.10.2 If
28、after testing, a test specimen shows evidence of adefect, the results of the test may be invalidated and anothermade 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 shall be made. Ifeither retest fails to meet
29、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 sufficient separately cast test pieces are no
30、t 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 the test requirements, the entire lot ofcas
31、tings 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 carrying out allthe tests and inspections requ
32、ired by this specification, usinghis own or other reliable facilities, and he shall maintaincomplete 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 specifica
33、tion where such inspectionsare deemed necessary to assure that supplies and servicesconform to the prescribed requirements.FIG. 4 Mold for Modified Keel BlockTABLE 2 Diameter and Length of Cast Test BarTest Bar NominalAs Cast Diameter, mm Length, mmMinimum Maximum Minimum MaximumB 30 29 31 150 230A
34、842 85 (2004)312. 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 specification and the re
35、quirements 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 pattern number at a l
36、ocation 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 shipmentshall be in accordance
37、 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 purchase order, marking f
38、or 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, chemi-cal composition,
39、 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 during and after solidif
40、ication, 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 proportions of nodular form an
41、d compacted formgraphite may 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 existence of bosses, p
42、rojections, 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 properties of a casting and
43、those of a test specimen castfrom the same iron. When such a relationship is important andmust be known for a specification application, it may bedetermined by appropriate experimentation.X1.3 When reliable information is unavailable on therelationship between properties in a casting and those in as
44、eparately 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 graphite cast iron in
45、this specification. Thechemical composition of the base iron used to produce com-pacted graphite cast iron may 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 143207 (5.04.2)350 16
46、3229 (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.A 842 85 (2004)4ASTM International takes no position respecting the validity of any patent rights asserted in connection with any it
47、em 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 com
48、mittee 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
49、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 ASTM International, 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 aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or throug
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