1、Designation: A 748/A 748M 87 (Reapproved 2008)Standard Specification forStatically Cast Chilled White Iron-Gray Iron Dual Metal Rollsfor Pressure Vessel Use1This standard is issued under the fixed designation A 748/A 748M; the number immediately following the designation indicates the yearof origina
2、l 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers statically cast dual metal rollswith the
3、 outer layer of the roll body being chilled white iron ofdifferent chemical composition than the core and journals ofthe roll which is gray cast iron. The castings are suitable forpressure containing parts, the design strength of which is basedon the gray iron portion of the cylinder. The castings a
4、resuitable for service at temperatures up to 450F 232C.1.2 The values stated in 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
5、from the two systems may result in non-conformancewith the standard.1.3 The following safety hazards statement pertains only tothe test method portion, 9, of this specification: This standarddoes not purport to address all of the safety concerns, if any,associated with its use. It is the responsibil
6、ity of the user of thisstandard to establish appropriate safety and health practicesand determine the applicability of regulatory limitations priorto use.2. Referenced Documents2.1 ASTM Standards:2A 278/A 278M Specification for Gray Iron Castings forPressure-Containing Parts for Temperatures Up to 6
7、50F(350C)A 667/A 667M Specification for Centrifugally Cast DualMetal (Gray and White Cast Iron) Cylinders3. Ordering Information3.1 Orders for material under this specification shall includethe following information:3.1.1 ASTM designation and year of issue,3.1.2 Dimensions of dual rolls,3.1.3 Class
8、of gray iron in the roll core (see 4.2),3.1.4 Inspection requirements, if different (see 10.1),3.1.5 Certification, if required (see 11.1), and3.1.6 Special position of marking information, if required(see 12.1).3.2 Any additional requirements not covered in this speci-fication are subject to agreem
9、ent between the manufacturer andpurchaser.4. Materials and Manufacture4.1 The melting procedure shall be optional with thefoundry.4.2 The chilled white iron exterior of the roll body shall bemade to a minimum hardness of 60 Scleroscope “C”. The grayiron portion of the roll shall conform to the appli
10、cable class ofSpecification A 278/A 278M, as determined by design require-ments. The scope of this specification shall include Nos. 20, 25,30, 35, 150, 175, 200, and 250 of Specification A 278/A 278M.4.3 The casting process shall be controlled to produce ametallurgical bond between the chilled white
11、 iron exterior andgray iron interior of the roll body.5. Test Requirements5.1 Tensile RequirementsTensile bars removed from aprolongation at one end of the roll journal, in accordance withSpecification A 278/A 278M, shall have a tensile strength notless than 80 % of that specified by the applicable
12、class ofSpecification A 278/A 278M.5.2 Thickness of Chilled White Iron:5.2.1 The thickness of the clear chilled white iron plus themottled iron at the roll face shall not be more than 30 % of thetotal finished wall thickness.5.2.2 The thickness of the chilled white iron exterior of theroll body shal
13、l be determined by measuring the chill depth atthe ends of the roll face.6. Finish6.1 All surfaces shall be machined or ground, or both, priorto the rolls being placed into service.1This specification is under the jurisdiction of ASTM Committee A04 on IronCastings and is the direct responsibility of
14、 SubcommitteeA04.01 on Grey and WhiteIron Castings.Current edition approved Oct. 1, 2008. Published December 2008. Originallyapproved in 1977. Last previous edition approved in 2003 as A 748/A 748M 87(2008).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
15、 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. Number of Tests7.1 The number of ten
16、sion tests shall be in accordance withSpecification A 278/A 278M.8. Specimen Preparation8.1 Test bars representing the gray iron portion of the rollshall be made from a prolongation at one end of the roll journalin accordance with Specification A 278/A 278M. Tension testspecimens machined from this
17、prolongation shall conform tothe dimensions shown for Specimen “C” in SpecificationA 278/A 278M.9. Test Method9.1 Tension test specimens shall fit the holders of the testingmachine in such a way that the load shall be axial. The use ofself-aligning shackles is suggested. After reaching a stressequiv
18、alent to 15 000 psi 100 MPa, the speed of the movinghead of the testing machine shall not exceed18 in. 3.2mm/min.10. Inspection10.1 The inspector representing the purchaser shall havefree entry at all times, while work on the contract of thepurchaser is being performed, to all parts of the manufactu
19、rersworks that concern the manufacture of the material ordered.The manufacturer shall afford the inspector all reasonablefacilities to satisfy him that the material is being furnished inaccordance with this specification. Unless otherwise specified,all tests and inspections shall be made at the plac
20、e ofmanufacture prior to the shipment, and shall be so conducted asnot to interfere unnecessarily with the operation of the works.11. Acceptance and Certification11.1 Final acceptance of the casting shall follow completemachining of the casting. Upon request of the purchaser andwhen so specified in
21、the purchase order, a certification shall bemade on the basis of acceptance of the material. This shallconsist of a copy of the manufacturers test report or astatement by the supplier, accompanied by a copy of the testresults, that the material has been sampled, tested, and in-spected in accordance
22、with the provisions of this specification.Each certification so furnished shall be signed by an authorizedagent of the supplier or manufacturer.12. Product Marking12.1 Pressure-containing castings made in accordance withthis specification shall have the name of the manufacturer orhis recognized trad
23、emark and the class of iron to which itconforms, cast or indelibly stamped on the surface indicated bythe purchaser or in such a position as not to injure theusefulness of the casting.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any it
24、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
25、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
26、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 Driv
27、e, 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 through the ASTM website(www.astm.org).A 748/A 748M 87 (2008)2
