1、Designation: A456/A456M 08 (Reapproved 2018)Standard Specification forMagnetic Particle Examination of Large CrankshaftForgings1This standard is issued under the fixed designation A456/A456M; the number immediately following the designation indicates the yearof original adoption or, in the case of r
2、evision, 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 is an acceptance specification for the magneticparticle inspection of forged steel crankshaf
3、ts having mainbearing journals or crankpins 4 in. 200 mm or larger indiameter.1.2 There are three classes, with acceptance standards ofincreasing severity:1.2.1 Class 1.1.2.2 Class 2 (originally the sole acceptance standard of thisspecification).1.2.3 Class 3 (formerly covered in Supplementary Requi
4、re-ment S1 of Specification A456 64 (1970).1.3 This specification is not intended to cover continuousgrain flow crankshafts (see Specification A983/A983M);however, Specification A986/A986M may be used for thispurpose.NOTE 1Specification A668/A668M is a product specification whichmay be used for slab
5、-forged crankshaft forgings that are usually twisted inorder to set the crankpin angles, or for barrel forged crankshafts where thecrankpins are machined in the appropriate configuration from a cylindricalforging.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separate
6、ly as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.5 Unless the order specifies the applicable “M” specifica-tion designati
7、on, the material shall be furnished to the inchunits.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued
8、 by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A275/A275M Practice for Magnetic Particle Examination ofSteel ForgingsA668/A668M Specification for Steel Forgings, Carbon andAlloy, for General Industrial UseA966/A966M Practice for
9、 Magnetic Particle Examination ofSteel Forgings Using Alternating CurrentA983/A983M Specification for Continuous Grain FlowForged Carbon and Alloy Steel Crankshafts for MediumSpeed Diesel EnginesA986/A986M Specification for Magnetic Particle Examina-tion of Continuous Grain Flow Crankshaft ForgingsE
10、1417/E1417M Practice for Liquid Penetrant Testing3. Classification of Indications3.1 Magnetic particle indications on the surface of thecrankshaft shall be classified as follows:3.1.1 Open cracks, flake, or pipe.3.1.2 Nonmetallic inclusions or stringers occurring in alongitudinal direction.3.1.3 Twi
11、st cracks or nonmetallic inclusions usually occur-ring at 45 to 70 from the axis of the journal.3.2 They shall also be classified as follows:3.2.1 Open indications are visible after removal of themagnetic particles or can be detected by the use of contrast dyepenetrant, as described in Type II of Pr
12、actice E1417/E1417M.3.2.1.1 Pinpoint indications are open indications116 in.1.5 mm in maximum dimension, as detected by application ofType II of Practice E1417/E1417M.3.2.2 Non-open indications are indications which are notvisually detectable as described in 3.2.1.1This specification is under the ju
13、risdiction 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 March 1, 2018. Published March 2018. Originallyapproved in 1999. Last previous edition approved in 2013 as A456/
14、A456M 08(2013). DOI: 10.1520/A0456_A0456M-08R18.2For 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.Copyright AST
15、M International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Stan
16、dards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14. Ordering Information4.1 The inquiry and purchase agreement shall contain astatement that the crankshaft(s) is (are) to be subject toacceptance according to this specification. If
17、reference to classis omitted, Class 2 shall apply.4.2 The use of Supplementary Requirements S1 and S2should be specified if required.5. Procedure5.1 Magnetic particle inspection shall be conducted accord-ing to Practice A966/A966M, except when SupplementaryRequirement S1 is to be used. The use of pr
18、od type contacts isnot permitted on finished crankshafts. Magnetic leeches mayonly be used on noncritical parts of the crankshaft whenSupplementary Requirement S2 is utilized.6. Areas of Inspection6.1 Major Critical Areas:6.1.1 The critical area of any crankpin shall be that area plusor minus 60 fro
19、m the 6 oclock position of the pin extending38 in. 10 mm above the thrust collar around the fillet, and58 in. 16 mm into the pin along its axis measured fromapproximately the blend of the pin surface and fillet, as shownin Fig. 1 and Fig. 2.6.1.2 The critical areas of any main bearing journal shall
20、bethat area plus or minus 60 from the 12 oclock position on topof the journal extending38 in. 10 mm above the thrust collararound the fillet and58 in. 16 mm into the journal along itsaxis measured from approximately the blend of the journalsurface and the fillet, as shown in Fig. 1 and Fig. 2.6.1.3
21、The critical area of any crankpin or main journal alsoincludes that surface area closer than14 in. 6 mm to thejunction of the radius blend and the journal surface of any oilhole.6.2 Minor Critical AreasMinor critical areas include allmachined fillets, thrust bearing, and bearing surfaces notspecifie
22、d as major critical areas.7. Acceptance Standards7.1 Class 1:7.1.1 Major Critical Areas:7.1.1.1 Open indications over14 in. 6 mm in length shallbe removed by dimpling to a depth no greater than316 in.5 mm. Open indications over116 to14 in. 1.5 to 6 mm inlength shall be depressed as in 7.2.2.3.7.1.1.
23、2 Pinpoint indications are permissible, except in clus-ters of more than 5 in any14 by14-in. 6 by 6-mm area, inwhich case they must be dimpled to a depth of no more than316 in. 5 mm. If they do not open or increase in number theyare acceptable and need not be removed.7.1.1.3 Non-open indications are
24、 acceptable up to andincluding12 in. 13 mm in length. If non-open indications areover12 in. 13 mm, depress, and if they are not open or areworsening, accept them. Otherwise remove by dimpling to amaximum depth of316 in. 5 mm.7.1.1.4 The total area of dimples shall be limited as in7.2.1.3.7.1.2 Minor
25、 Critical Areas:7.1.2.1 Open indications oriented at an angle in excess of30 to the longitudinal axis must be removed to a depth notexceeding316 in. 5 mm, by dimpling.Metric Equivalents38 in. = 10 mm58 in. = 16 mmFIG. 1 Critical Surface Areas of Crankpin and Main Bearing JournalA456/A456M 08 (2018)2
26、7.1.2.2 Open indications longer than 112 in. 38 mmindividually or more than 3 in. 75 mm of total length perbearing journal, that are parallel to the longitudinal axis within30, must be removed by dimpling to a depth no greater than316 in. 5 mm. Intermittent open indications in a line, spacedless tha
27、n14 in. 6 mm apart, shall be considered continuous oras one indication.7.1.2.3 Open indications18 in. 3 mm to 112 in. 38 mmlong, with the exception of those referred to in 7.1.2.1, shall bedepressed 0.003 to 0.010 in. 0.05 to 0.25 mm below thesurface but need not be removed.7.1.2.4 Open indications
28、less than18 in. 3 mm long neednot be depressed, dimpled, or removed.7.1.2.5 A cluster of open indications, with the exception ofthose referred to in 7.1.2.1, having a total length not exceeding212 in. 65 mm in any 1 by 1-in. 25 by 25-mm square areaof bearing surface shall be depressed 0.002 to 0.010
29、 in. 0.05to 0.25 mm below the surface but need not be removed. Whenthe total length exceeds 212 in. 65 mm, the indications are tobe removed by dimpling to a depth no greater than316 in.5 mm.7.1.2.6 Non-open indications are acceptable.7.1.2.7 The total area of dimples in any journal or crankpinshall
30、not exceed 1 % of the total minor critical area of thecrankpin or main journal concerned.7.1.3 Number of DimplesThe number of dimples percrankshaft, excluding dimples in the areas defined in 6.1.3,shall not exceed the sum of the number of the crankpins andmain journals, nor five per crankpin or main
31、 journal.7.2 Class 2:7.2.1 Major Critical Areas:7.2.1.1 Open indications other than pinpoints are not per-mitted and must be removed by dimpling to a depth no greaterthan316 in. 5 mm. Pinpoint indications are permissible, ifthere are no more than three in any14 by14-in. 6 by 6-mmsquare area. Pinpoin
32、ts in excess of three must be dimpled to adepth of316 in. 5 mm and reduced to no more than threepinpoints unless they are removed at a lesser depth. If no morethan three pinpoints remain at the316-in. 5-mm depth, theyare acceptable and need not be removed.7.2.1.2 Magnetic particle buildup exceeding1
33、4 in. 6 mmin length and which has been found to be non-open by theprocedure described in 3.2.1 shall be jointly investigated by themanufacturer and purchaser, or their representatives. Eachindication, or, with the concurrence of the purchaser, selectedrepresentative indications, shall be explored to
34、 a depth of atleast 0.003 in. 0.05 mm, but not exceeding 0.010 in.0.25 mm. If open indications are found (3.2.1), then therequirements of 7.2.1.1 shall apply. If open indications are notfound, then the indications are acceptable and any exploredarea shall be suitable radiused and classed as a depres
35、sed arearather than a dimple. If the presence of subsurface discontinui-ties is to be investigated, then Practice A275/A275M shall beincluded in such an investigation. However, caution should beexercised in demagnetizing the crankshaft on completion ofthis examination.7.2.1.3 The total area of dimpl
36、es shall be less than 10 % ofthe total major critical area of the crankpin or journal con-cerned. The areas referred to in 6.1.3 shall be excluded fromthe total area allowable.7.2.2 Minor Critical Areas:7.2.2.1 Open indications oriented at an angle in excess of30 to the longitudinal axis must be rem
37、oved at a depth notexceeding316 in. 5 mm, by dimpling.7.2.2.2 Open indications longer than 1 in. 25 mm indi-vidually or more than 2 in. 50 mm of total length per bearingjournal, that are parallel to the longitudinal axis within 30,must be removed by dimpling to a depth no greater than316 in.5 mm. In
38、termittent open indications in a line, spaced less than14 in. 6 mm apart, shall be considered continuous or as oneindication.(1)58 in. 16 mm on pin or journal,(2)Fillet radius, R,(3)Thrust collar, and(4)38 in. 10-mm ring beyond thrust collar.NOTE 1The critical area is 120 on the pin or journal.FIG.
39、2 Reference Dimensions for CalculationsA456/A456M 08 (2018)37.2.2.3 Open indications18 to 1 in. 3 to 25 mm long, withthe exception of those referred to in 7.2.2.1, shall be depressed0.003 to 0.010 in. 0.05 to 0.25 mm below the surface but neednot be removed.7.2.2.4 Open indications less than18 in. 3
40、 mm long neednot be depressed, dimpled, or removed.7.2.2.5 A cluster of open indications, with the exception ofthose referred to in 7.2.2.1, having a total length not exceeding112 in. 38 mm in any 1 by 1-in. 25 by 25-mm square areaof bearing surface, shall be depressed 0.002 to 0.010 in. 0.05to 0.25
41、 mm below the surface but need not be removed. Whenthe total length exceeds 112 in. 38 mm, the indications are tobe removed by dimpling to a depth no greater than316 in.5 mm.7.2.2.6 Non-open indications are acceptable.7.2.2.7 The total area of dimples in any journal or crankpinshall not exceed 1 % o
42、f the total minor critical area of thecrankpin or main journal concerned.7.2.3 Number of DimplesThe number of dimples percrankshaft, excluding dimples in the areas defined in 6.1.3,shall not exceed the sum of the number of the crankpins andmain journals, nor five per crankpin or main journal.7.3 Cla
43、ss 3:7.3.1 Major Critical AreasSee 7.2.1.7.3.2 Minor Critical Areas:7.3.2.1 Open indications oriented at an angle in excess of30 to the longitudinal axis must be removed at a depth notexceeding316 in. 5 mm, by dimpling.7.3.2.2 Open indications longer than18 in. 3 mm that areparallel to the longitudi
44、nal axis within 30 must be removed bydimpling to a depth no greater than316 in. 5 mm. Intermittentopen indications in a line, spaced less than14 in. 6 mm apart,shall be considered continuous or as one indication.7.3.2.3 Open indications (except pinpoint indications)18 in.3 mm or less in length, with
45、 the exception of those referredto in 7.3.2.1, shall be depressed 0.002 to 0.010 in. 0.05 to0.25 mm, below the surface, but need not be removed.7.3.2.4 Non-open indications are acceptable.7.3.2.5 The total areas of dimples in any journal or crankpinshall not exceed 1 % of the total minor critical ar
46、ea of thecrankpin of main journal concerned.8. Dimpling and Depressing8.1 To dimple means to stone or grind to remove stock in anarea that contains an open indication. All dimples shall have abottom radius of approximately three times the dimple depthand should be smoothly blended to the surface are
47、a with afinish equal to the adjacent bearing surface.8.2 To depress is to flatten or relieve the edges of anindication with a fine pointed abrasive stone with the restrictionthat the depth beneath the original surface shall be 0.002 in.0.05 mm minimum to 0.010 in. 0.25 mm maximum and thatthe depress
48、ions be blended into the bearing surface. A de-pressed area is not considered a dimple and is made only toprevent galling of the bearings.9. Inspection9.1 The manufacturer shall afford the purchasers inspectorall reasonable facilities necessary to satisfy him that thematerial is being produced and f
49、urnished in accordance withthis specification. All tests and inspections shall be made at theplace of manufacture, unless otherwise agreed to, and shall notinterfere unnecessarily with the manufacturers operations.9.2 Upon agreement with the purchaser or if expressed inthe order or if shown on the drawing, the manufacturer of thecrankshaft shall certify that the cranksha
