1、Designation:A80295(Reapproved 2015)Standard Practice forSteel Castings,Surface Acceptance Standards,VisualExamination1This standard is issued under the fixed designation A802;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year o
2、f last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This practice covers the acceptance
3、criteria for thesurface inspection of steel castings by visual examination.Fourlevels of acceptance standards are provided.1.2 Acceptance levels utilize Steel Castings Research andTrade Association(SCRATA)2graded reference comparatorsfor the visual determination of surface texture,surfaceroughness,a
4、nd surface discontinuities described as follows:Acceptance levelsASurface TextureBNonmetallic InclusionsCGas PorosityDSolidification DiscontinuitiesESand Expansion DiscontinuitiesFMetal InsertsGThermally Cut SurfacesHMechanically Prepared SurfacesJWelded Surfaces1.3 Descriptions of terms related to
5、casting discontinuitiesare in Section 2.1.4 This standard does not purport to address all of thesafety concerns,if any,associated 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 lim
6、itations prior to use.2.Terminology2.1 Definitions of Terms Specific to This Standard:2.1.1 expansion discontinuities:2.1.1.1 veins,nraised,narrow,linear ridges that formupon cracking of the sand mold or core due to expansion ofsand and the resulting mold or core stresses during filling of themold w
7、ith liquid steel.2.1.1.2 rat tails,nlong,narrow,linear depressions orsmall steps occurring on a casting surface.Rat tails form as aresult of sand expansion and minor buckling of the moldsurface during filling of the mold with liquid metal.2.1.1.3 scab,na raised,rough area on a casting thatusually co
8、nsists of a crust of metal covering a layer of sand.Sometimes,a scab consists of a raised,rough area of essen-tially solid metal on the surface of a casting.2.1.2 external chills:2.1.2.1 external chills,nusually metal blocks,or graphiteand carbon blocks,that are incorporated into the mold tolocally
9、increase the rate of heat removal during solidification.Brackets have the same purpose but represent an integral partof the casting.Brackets are produced by providing suitablecavities in the mold or core.External chills may produce flatspots and edges(raised areas or depressions)on the castingsurfac
10、e.Brackets merely change the casting appearance due totheir presence.Brackets may be removed or allowed to remainon the casting.2.1.2.2 parting line and core print fins,nthin projectionsof excess metal at the parting plane between mold halves orcore and mold.Causes are improper closing of the mold,i
11、nsufficient weighting or clamping of the mold for pouring,oruneven pattern surfaces at the matching locations.Core printfins are usually caused by improper dimensions of core printsof the pattern or core box,by rough placement of cores in a softmold,or by inadequately secured cores.2.1.3 fusion disc
12、ontinuities:2.1.3.1 wrinkles,nelongated,smooth depressions of thecasting surface,frequently appearing in closely spaced groups.Wrinkles result from irregularities of the liquid metal flow inthe mold cavity,frequently associated with low temperature,and are distinguished from the more severe phenomen
13、on oflaps,folds,or cold shuts where the casting surface is actuallyfolded over.1This practice is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloysand is the direct responsibility of SubcommitteeA01.18 on Castings.Current edition approved Nov.1,2015.Published No
14、vember 2015.Originallyapproved in 1982.Last previous edition approved in 2010 as A802/A802M 95(2010)2.DOI:10.1520/A0802-95R15.2Available from Castings Technology International,Advanced ManufacturingPark,Brunel Way,Rotherham,S60 5WG,South Yorkshire,England.http:/.Copyright ASTM International,100 Barr
15、 Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 2.1.3.2 laps,folds,and cold shuts,ninterchangeableterms to describe the appearance of the casting surface that isactually folded over.They develop due to low temperature,unfavorable flow conditions caused by oxide films,or comb
16、i-nations thereof.2.1.3.3 misrun,nan incompletely formed casting,due toonly partial filling of the mold cavity when the liquid metalsolidifies prematurely.The resulting casting appearance ischaracterized by rounded edges,for a mild degree of misrun.Irregular,malformed edges of more severe misruns,and notfully formed castings,are characteristic.Frequently,misrunsare associated with such discontinuities as wrinkles or laps andfolds,or both.2.1.4 gas porosity,na concave discontinuity in castingsdue