1、Designation:A99708(Reapproved 2012)Standard Practice forInvestment Castings,Surface Acceptance Standards,VisualExamination1This standard is issued under the fixed designation A997;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the y
2、ear of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers the acceptance criteria for surfaceinspection of investment castings by visual examination.1.2
3、The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated
4、with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Terminology2.1 Definitions of Terms Specific to This Standard:2.1.1 linear discontinuity,na discontinuity
5、whose lengthis equal to or greater than three times its width.Cracks and coldshuts are examples of linear discontinuity.2.1.2 positive metal,nraised metal on the casting surfaceusually associated with the breakdown of the mold and itsreplacement with the casting metal.2.1.3 surface pit,na non linear
6、 depression in the castsurface whose length is less than three times its width.Surfacepits may be the result of gas or non metallic inclusions.2.1.4 surface roughness,na measure of surface textureusually determined by the use of a comparator.3.Ordering Information3.1 The inquiry or order should spec
7、ify the followinginformation:3.1.1 Acceptance LevelMore than one acceptance levelmay be specified for different surfaces of the same casting(seeSection 4),3.1.2 If any types of discontinuities are unacceptable,3.1.3 Casting surfaces to be examined,3.1.4 Number of castings to be examined,and3.1.5 Add
8、itional acceptance criteria as applicable to all orportions of the casting surface.4.Acceptance Criteria4.1 Levels of acceptance for visual inspection are listed inTable 1.4.2 Parts shall not exhibit any linear discontinuities.4.3 Surface roughness and surface pits that will be removedby machining a
9、re considered acceptable.4.4 Surface discontinuities not covered in this practice shallbe a matter of agreement between the purchaser and themanufacturer.1This practice is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of Sub
10、committeeA01.18 on Castings.Current edition approved Sept.1,2012.Published November 2012.Originallyapproved in 1998.Last previous edition approved in 2008 as A997 08.DOI:10.1520/A0997-08R12.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1
11、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 en
12、tirely 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 either for revision of this standard or for additional standardsand
13、 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 St
14、andards,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 610-832-95
15、85(phone),610-832-9555(fax),or serviceastm.org(e-mail);or through the ASTM website(www.astm.org).Permission rights to photocopy the standard may also be secured from the ASTM website(www.astm.org/COPYRIGHT/).TABLE 1 Visual Inspection Acceptance CriteriaA,BSurface FeatureLevel IILevel IIILevel IVSurf
16、ace PitsC,D,E0.030 in.(0.76mm)diameter by0.015 in.(0.38mm)deep with nomore than 1 per in.2(645 mm2)0.060 in.(1.52mm)diameter by0.030 in.(0.76mm)deep with nomore than 1 per in.2(645 mm2)0.060 in.(1.52mm)diameter by0.030 in.(0.76mm)deep with nomore than 4 per in.2(645 mm2)Positive MetalD,E0.060 in.(1.52mm)diameter by0.015 in.(0.38mm)high with nomore than 1 per in.2(645 mm2)0.125 in.(3.18mm)diameter by0.030 in.(0.76mm)high with nomore than 1 per in.2(645 mm2)0.125 in.(3.18mm)diameter by0.030 in.(0.
