1、Designation:A986/A986M01(Reapproved 2016)Standard Specification forMagnetic Particle Examination of Continuous Grain FlowCrankshaft Forgings1This standard is issued under the fixed designation A986/A986M;the number immediately following the designation indicates the yearof original adoption or,in th
2、e 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 the magnetic particle exami-nation of forged continuous grain flo
3、w(CGF)crankshaftsintended for medium speed diesel engines.1.2 For the purpose of magnetic particle indicationassessment,the crankshaft is divided into four zones ofdecreasing operational stress.Acceptance criteria have been setfor each zone.1.3 The engines to which these crankshafts are fitted areco
4、mmonly used for diesel electric locomotives,marinepropulsion,and power generation.Engines fueled by naturalgas also fall into this medium speed category.1.4 Specification A983/A983M is a product specificationthat covers the manufacture of CGF crankshafts.1.5 The values stated in either inch-pound un
5、its or SI unitsare to be regarded separately as standard.Within the text,theSI units are shown in brackets.The values stated in eachsystem are not exact equivalents;therefore,each system shallbe used independently of the other.Combining values from thetwo systems may result in nonconformance with th
6、e specifi-cation.2.Referenced Documents2.1 ASTM Standards:2A788/A788M Specification for Steel Forgings,General Re-quirementsA966/A966M Practice for Magnetic Particle Examination ofSteel Forgings Using Alternating CurrentA983/A983M Specification for Continuous Grain FlowForged Carbon and Alloy Steel
7、Crankshafts for MediumSpeed Diesel Engines3.Ordering Information3.1 Specification A983/A983M requires that crankshaftsmade to that specification be examined in accordance withSpecification A986/A986M for magnetic particle examination.It is the responsibility of the purchaser to specify any changesto
8、 the zone allocations for the crankshaft surfaces.4.Procedure4.1 Magnetic particle examination shall be conducted inaccordance with Practice A966/A966M.The use of prod typecontacts is not permitted on finished crankshaft surfaces.Magnetic leeches may be used only on flat noncritical surfaces,and wit
9、hin the limitations specified in Practice A966/A966M.4.2 The magnetic particle examination shall be conductedusing the wet fluorescent method described in Practice A966/A966M.5.Areas of Examination5.1 Zone 1Major Critical Areas:5.1.1 Crankpin JournalsThe major critical area of eachcrankpin journal s
10、hall include that area 660 from the 6 oclockposition of the crankpin and extend38in.10 mm above thefillet collar and58in.15 mm along the crankpin surface asmeasured from the blend of the fillet radius and the journalsurface.These positions are shown in Fig.1.5.1.2 Main Bearing JournalsThe major crit
11、ical areas ofany main bearing journal shall include that area 660 from the12 oclock position on top of the journal and extend38in.10 mm above the fillet collar and58in.15 mm along thejournal as measured from the blend of the fillet radius and thejournal surface.These positions are shown in Fig.1.5.1
12、.3 Oil HolesThe major critical areas in also shallinclude the surfaces surrounding the journal oil holes.Thediameter of this critical area shall be 3d,where d is the oil holediameter before the radius.The critical area shall be centeredon the centerline of the oil hole.In addition,the Zone 1 critica
13、larea shall extend down the oil hole for a distance from thejournal surface equal to the hole diameter.5.2 Zone 2Minor Critical Areas:5.2.1 The Zone 2 minor critical areas shall include thebalance of the fillet radii of the crankpin and main bearingjournals not included in the major critical areas.1
14、This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.06 on Steel Forgings and Billets.Current edition approved Sept.1,2016.Published September 2016.Originallyapproved in 1998.Last previous e
15、dition approved in 2011 as A986/A986M 01(2011).DOI:10.1520/A0986_A0986M-01R16.2For 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 A
16、STM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2.2 When counterweights are attached to the crankshaftwebs by welding,the weld surfaces and12in.13 mm of theadjacent surfaces shall be considered minor critical areas.5.3 Zone 3Journal Running Surfaces:5.3.1 Zone 3 includes the remainder of the crankpin andmain bearing journal surfaces not covered by the major andminor critical areas.5.3.2 Zone 3 also includes the bearing j
