1、Designation: A 456/A 456M 08Standard Specification forMagnetic Particle Examination of Large CrankshaftForgings1This standard is issued under the fixed designation A 456/A 456M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the y
2、ear 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. Scope*1.1 This is an acceptance specification for the magneticparticle inspection of forged steel crankshafts having mai
3、nbearing 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 Require-ment S1 of
4、 Specification A 456 64 (1970).1.3 This specification is not intended to cover continuousgrain flow crankshafts (see Specification A 983/A 983M);however, Specification A 986/A 986M may be used for thispurpose.NOTE 1Specification A 668/A 668M is a product specification whichmay be used for slab-forge
5、d 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 separately as
6、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 designation, th
7、e material shall be furnished to the inchunits.2. Referenced Documents2.1 ASTM Standards:2A 275/A 275M Practice for Magnetic Particle Examinationof Steel ForgingsA 668/A 668M Specification for Steel Forgings, Carbonand Alloy, for General Industrial UseA 966/A 966M Practice for Magnetic Particle Exam
8、inationof Steel Forgings Using Alternating CurrentA 983/A 983M Specification for Continuous Grain FlowForged Carbon and Alloy Steel Crankshafts for MediumSpeed Diesel EnginesA 986/A 986M Specification for Magnetic Particle Exami-nation of Continuous Grain Flow Crankshaft ForgingsE 1417 Practice for
9、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 Twist cracks or nonmetallic
10、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 Practice E 1417.3.2.1.1 Pin
11、point indications are open indications116 in. 1.5mm in maximum dimension, as detected by application ofType II of Practice E 1417.3.2.2 Non-open indications are indications which are notvisually detectable as described in 3.2.1.4. Ordering Information4.1 The inquiry and purchase agreement shall cont
12、ain astatement that the crankshaft(s) is (are) to be subject toacceptance according to this specification. If 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 con
13、ducted accord-ing to Practice A 966/A 966M, except when SupplementaryRequirement S1 is to be used. The use of prod type contacts is1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys , and is the direct responsibility of SubcommitteeA01.06
14、on Steel Forgings and Billets.Current edition approved Oct. 1, 2008. Published October 2008. Originallyapproved in 1999. Last previous edition approved in 2003 as A 456/A 456M 99(2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceast
15、m.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United St
16、ates.not 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 from the 6 oclock
17、 position of the pin extending38 in. 10 mm above the thrust collar around the fillet, and58in. 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 bethat area plu
18、s 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 The critical ar
19、ea 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 notspecified as major crit
20、ical 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. 5mm. Open indications over116 to14 in. 1.5 to 6 mm inlength shall be depressed as in 7.2.2.3.7.1.1.2 Pinpoint indi
21、cations 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 than316in. 5 mm. If they do not open or increase in number they areacceptable and need not be removed.7.1.1.3 Non-open indications are acceptable up t
22、o 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 Critical Areas:
23、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.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
24、longitudinal axis within30, must be removed by dimpling to a depth no greater than316 in. 5 mm. Intermittent open indications in a line, spacedless than14 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 o
25、f 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 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
26、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 in. 0.05Metric Equivalents38 in. = 10 mm58 in. = 16 mmFIG. 1 Critical Surface Areas of Crankpin and Main Bearing JournalA 456/A 456M 082to 0.25 mm b
27、elow 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. 5mm.7.1.2.6 Non-open indications are acceptable.7.1.2.7 The total area of dimples in any journal or crankpinshall not exceed 1 % of the
28、 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 journal.7.2 Class 2:
29、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. Pinpoints in excess of three
30、 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 exceeding14 in. 6 mmin length a
31、nd 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 a depth of atleast 0
32、.003 in. 0.05 mm, but not exceeding 0.010 in. 0.25mm. If open indications are found (3.2.1), then the require-ments of 7.2.1.1 shall apply. If open indications are not found,then the indications are acceptable and any explored area shallbe suitable radiused and classed as a depressed area rather tha
33、na dimple. If the presence of subsurface discontinuities is to beinvestigated, then Practice A 275/A 275M shall be included insuch an investigation. However, caution should be exercised indemagnetizing the crankshaft on completion of this examina-tion.7.2.1.3 The total area of dimples shall be less
34、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 removed at a depth n
35、otexceeding316 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. Intermittent open i
36、ndications in a line, spaced less than14 in. 6 mm apart, shall be considered continuous or as oneindication.7.2.2.3 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 re
37、moved.7.2.2.4 Open indications less than18 in. 3 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, s
38、hall be depressed 0.002 to 0.010 in. 0.05to 0.25 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. 5mm.7.2.2.6 Non-open indications are acceptable.7.2.2.7 The total area of dimples
39、in any journal or crankpinshall not exceed 1 % of the total minor critical area of thecrankpin or main journal concerned.(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.NOTEThe critical area is 120 on the pin or journal.FIG. 2 Refe
40、rence Dimensions for CalculationsA 456/A 456M 0837.2.3 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 Class 3:7.3.1 Major Critica
41、l 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 longitudinal axis within 30 must
42、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 the exception of those
43、referredto in 7.3.2.1, shall be depressed 0.002 to 0.010 in. 0.05 to 0.25mm, 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 area of thecrankpin of mai
44、n 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 area with afinish equal to
45、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 depressions be blended into the
46、 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 furnished in accordance w
47、iththis 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
48、 of thecrankshaft shall certify that the crankshaft was tested and is inaccordance with this specification.10. Product Marking10.1 The purchaser of the crankshaft shall provide themanufacturer with any marking or stamping identificationrequired.11. Keywords11.1 acceptance criteria; barrel forged cra
49、nkshaft; crank-shaft forgings; magnetic particle examination; nondestructiveexamination; slab forged crankshaftSUPPLEMENTARY REQUIREMENTSThe following supplementary requirements shall apply only when specified by the purchaser in thecontract or order.S1. Use of Direct Current MagnetizationS1.1 The magnetic particle examination of the crankshaftshall be done in accordance with Practice
