1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.TO PLACE A DOCUMENT ORDER: +01 724-776-4970 FAX: +01 724-776-0790SAE WEB ADDRESS http:/w
3、ww.sae.orgCopyright 2000 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001STANDARDSubmitted for recognition as an American National StandardJ431REV.DEC2000Issued 1935-01Revised 2000-12Superseding J431 AUG1996(R)
4、 Automotive Gray Iron Castings1. ScopeThis SAE Standard covers the hardness, tensile strength, and microstructure and specialrequirements of gray iron sand molded castings used in the automotive and allied industries. Specificrequirements are provided for hardness of castings. Test bar tensile stren
5、gth/Brinell hardness (t/h) ratiorequirements are provided to establish a consistent tensile strength-hardness relationship for each grade tofacilitate prediction and control of tensile strength in castings. Provision is made for specification of specialadditional requirements of gray iron automotive
6、 castings where needed for particular applications and serviceconditions.NOTEThis document was revised in 1993 to provide grade specific t/h control. In 1999 the document wasrevised to make SI metric units primary. To better align the grading system with long establishedproduction methods and grades
7、 produced, the previous system of grading by fixed combinations oftensile strength and hardness was changed in 1999 to a system of grading by variable combinations oftest bar t/h ratio and casting hardness grades. The number of hardness grades was increased relativeto the number of previously availa
8、ble ranges to facilitate centering of casting mean hardness in thespecification range so that dependence of cost optimization on controlling near the low or high sides ofspecification ranges is minimized.2. References2.1 Applicable PublicationsThe following publications form a part of this specifica
9、tion to the extent specifiedherein. Unless otherwise indicated, the latest issue of SAE publications shall apply.2.1.1 SAE PUBLICATIONAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J417Hardness Tests and Hardness Number Conversions2.1.2 ASTM PUBLICATIONSAvailable from ASTM
10、, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.ASTM A 48Specification for Gray Iron CastingsASTM A 247Recommended Practice for Evaluating the Microstructure of Graphite in Iron CastingsASTM A 438Transverse Testing of Gray Cast IronASTM E 10Test for Brinell Hardness of Metallic MaterialsAS
11、TM E 562Determining Volume Fraction by Systematic Manual Point CountCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE J431 Revised DEC2000-2-2.2 Related PublicationsThe following publications are pro
12、vided for information purposes only and are not arequired part of this document. Additional information concerning gray iron castings, their properties, and usecan be obtained from:1. Metals Handbook, Vol. 1, 10th Edition, ASM International, Materials Park, OH2. Cast Metals Handbook, American Foundr
13、ymens Society, Des Plaines, IL3. 1981 Iron Castings Handbook, Iron Castings Society, Inc., Cleveland, OH4. H.D. Angus, “Physical and Engineering Properties of Cast Iron,” British Cast Iron ResearchAssociation, Birmingham, England, 2nd Edition, 19765. “Gray, Ductile, and Malleable Iron Castings Curre
14、nt Capabilities,” STP-455, American Society forTesting and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-29596. G.N.J. Gilbert, “Engineering Data on Grey Cast Iron,” BCIRA (1977), Alvechurch, Birmingham,England7. “Tables for Normal Tolerance Limits, Sampling Plans and Screening,” R.E
15、. Odeh and D.B. Owen,Marcel Dekker, Inc., New York and Basel, 19808. “Fatigue Properties of Gray Cast Iron,” L.E. Tucker and D.R. Olberts, SAE Paper 6904713. Grade definition and Designation.3.1 Iron GradeGray iron grades, defined by their minimum test bar t/h ratio, are designated by the letter Gfo
16、llowed by a number equaling the defining minimum test bar t/h ratio multiplied by 100. The units used for thispurpose are MPa for both tensile strength and hardness. The t/h ratio is dimensionless.EXAMPLEG10 designates a gray iron having minimum test bar t/h = 0.100.3.2 Hardness GradeHardness grades
17、, defined by minimum hardness exhibited in castings, are designated bythe letter H followed by a number equaling the minimum casting hardness divided by 100. The castinghardness unit used for this purpose is the MPa.EXAMPLEH18 designates minimum casting hardness of 1800 MPa.3.3 Casting GradeSAE gray
18、 iron casting grades are defined and designated by combining the iron grade andthe hardness grade designations.EXAMPLEG10H18 designates iron in castings with minimum test bar t/h of 0.100 MPa/MPa and minimumcasting hardness of 1800 MPa.3.4 Special RequirementsSpecial requirements, defined for specia
19、l applications, are designated by alowercase suffix letter placed at the end of the casting grade designation.EXAMPLE11H20b designates iron meeting special requirements of special service brakedrums.3.5 Equivalency and ConversionEquivalency information for engineering purposes, between this and othe
20、rstandards, is provided in A.4.1, A.4.6, and A.4.7. Grades of this document can have multiple equivalents withgrades of previous SAE and most other standards as exemplified by grades G3000 and G4000. Determinationof current grade equivalent for castings established in production under previous SAE o
21、r other documents,shall be by the producer, in accordance with 5.5.3, based on historical or current test data from the establishedprocess, and reported to and approved by the purchaser. When the producer does not have access to theapplicable historical data, grade determination shall be based on sa
22、mples provided by producer and approvedby purchaser.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE J431 Revised DEC2000-3-4. Grades4.1 Iron GradesIron grades and their t/h lower limit requirements
23、 are shown in Table 1.4.2 Hardness GradesHardness grades and their required lower hardness limits are shown in Table 2. 4.3 Special RequirementsSpecial additional requirements for particular applications and service conditionsand their lower case letter designators are shown in Table 3. Special addi
24、tional requirements shall not changetest bar t/h ratio or casting hardness requirements.TABLE 1IRON GRADESGradeTest Bar t/hRatio Lower Limit(1)MPa/MPa(2)1. Statistically defined2. Both tensile and hardness in MPA unitsTest Bar t/hRatio Lower Limit(1)psi/HB(3)(4)3. For reference only. The MPa/MPa SI
25、metric values are primary. See Section 1.4. Units of HB are kgf per mm2.G7 0.070 100G9 0.090 128G10 0.100 142G11 0.110 156G12 0.120 171G13 0.130 185TABLE 2HARDNESS GRADESGradeCasting HardnessLower Limit(1)MPa(2)1. Statistically Defined.2. Hardness in MPa = HB multiplied by 9.80665.Casting HardnessLo
26、wer Limit(1)HB(3)3. Units of HB are kgf per mm2.H10 1000 102H11 1100 112H12 1200 122H13 1300 133H14 1400 143H15 1500 153H16 1600 163H17 1700 173H18 1800 184H19 1900 194H20 2000 204H21 2100 214H22 2200 224H23 2300 235H24 2400 245Copyright SAE International Provided by IHS under license with SAENot fo
27、r ResaleNo reproduction or networking permitted without license from IHS-,-SAE J431 Revised DEC2000-4-4.4 Casting GradesCombination of iron grade, hardness grade, and special requirement designation, if any,defines casting grade. A partial list of casting grades in common production and use, identif
28、ied as referencegrades and considered standard, is given in Table 4 with current and previous SAE designations. Othercombinations of iron grade and hardness grade which are established in production and use or become so inthe course of application development, or in accordance with 3.5 and 5.5.3, ar
29、e also considered standard. NOTEFor castings successfully established in production and use under previous designations, the currentSAE casting grade shall be determined by the producer and approved by the purchaser (see 3.5).TABLE 3SPECIAL REQUIREMENTSDesignator Application Requirementsa Brake Drum
30、s and Discs and Clutch Plates for Special Service1. Total Carbon 3.4% minimum.2. Microstructure: Lamellar Pearlite. Ferrite 15%(1)1. See ASTM E 562.b Brake Drums and Discs and Clutch Plates for Special Service1. Total Carbon 3.4% minimum.2. Microstructure: Lamellar Pearlite. Ferrite or carbide 5%(1)
31、c Brake Drums and Discs and Clutch Plates for Special Service1. Total Carbon 3.5% minimum.2. Microstructure: Lamellar Pearlite. Ferrite or carbide 5%(1)d Alloy Hardenable Gray Iron Automotive Camshafts(2)2. As-cast requirements. Camshafts may be flame or induction hardened to specified hardness and
32、depth on cam sur-faces.1. Chromium shall be 0.85 to 1.50%(3)2. Molybdenum shall be 0.40 to 0.60%(3)3. Microstructure of cam nose:Extending to 45 degrees on both sides of cam nose centerlineand to minimum depth of 3.2 mm from the surface shall consistof primary carbide (cellular and/or acicular) and
33、graphite in amatrix of fine pearlite.4. The amount of carbide in the cams and method of checking shallbe specified by the purchaser.5. Casting Hardness check location shall be on a bearing surface.3. Ranges for specific castings shall be within the ranges shown.TABLE 4REFERENCE GRADES(1)1. Establish
34、ed in production and use and having near equivalents with previous SAE designations.SAE Casting Grade Previous SAE Designation(2)2. Equivalency based on tensile strength in 30 mm diameter test bars. See Table A4.G9H12 G1800G9H17 G2500G10H18 G3000G11H18 G3000G11H20 G3500G12H21 G4000G13H19 G4000G7H16
35、c G1800 h(3)3. The h suffix was previously used to designate both t/h and carbon require-ments for this grade.G9H17 a G2500 aG10H21 c G3500 cG11H20 b G3500 bG11H24 d G4000 dCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without
36、 license from IHS-,-SAE J431 Revised DEC2000-5-5. Tensile Strength to Hardness Ratio, Hardness, and Casting Tensile Strength5.1 Tensile strength values for the t/h ratio determination shall be obtained as shown in Figure 1 from separatelycast 30 mm test bars (type “B”) in accordance with ASTM A 48 e
37、xcept sampling frequency shall be as neededfor statistical analysis to determine conformance of t/h ratio with requirements of this document. Testspecimens shall be at room temperature, defined as between 10 and 35 C, during tensile testing.FIGURE 1TEST BAR HARDNESS LONGITUDINAL TEST ZONEIN RELATION
38、 TO TENSILE SPECIMEN5.2 Test bar hardness for the t/h ratio determination shall be taken on the tensile test bar between bar center andmidpoint of the as-cast radius, and between 50 and 75 mm from the as-cast bar end as shown in Figures 1 and2.FIGURE 2TEST BAR HARDNESS RADIAL TEST ZONE5.3 Brinell Ha
39、rdness is considered standard for test bars and production castings and shall be determinedaccording to ASTM E 10 after sufficient material has been removed from the casting surface to insurerepresentative hardness readings. The 10 mm ball and 3000 kgf load shall be used unless physicallyprecluded b
40、y specimen dimensions as given in ASTM E 10. Test specimens shall be at room temperature,defined as between 10 and 35 C, during hardness testing. 5.3.1 When a hardness test other than the Brinell test with 10 mm ball and 3000 kgf load must be used, conversionto the 3000 kgf 10 mm ball equivalent sha
41、ll be by applicable conversion table in SAE J417 or by on-sitecalibration using Standard Brinell Bars. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE J431 Revised DEC2000-6-5.4 A non-destructive c
42、asting hardness test location on the casting for monitoring conformance to grade limits shallbe established by agreement between purchaser and producer or determined by producer. It should be readilyaccessible for convenience in performing the test to ensure adequate quantity, consistency, and accur
43、acy ofaccumulated data for statistical validity in service of general variance control. Targeting of hardnessmeasurement at service function related locations shall not be considered a requirement unless specified inaccordance with 5.4.1.5.4.1 In special cases, casting hardness at particular casting
44、 locations considered critical by the designer butdifficult to access or requiring casting destruction may be specified by the purchaser with produceragreement. In such cases, hardness grade conformance may be established directly by hardness readingsso obtained or indirectly by hardness readings at
45、 an accessible location using an agreed method ofcorrelation.5.5 The foundry shall exercise the necessary controls and inspection techniques to ensure compliance with thespecified hardness and t/h ratio minimums. When samples exhibit normal variance patterns, conformancewith grade requirements for t
46、/h and casting hardness shall be determined by long term analysis of productionsamples using Normal Curve statistical methods. For sample sizes less than 30, the lower limit shall be takenas 3 standard deviations below the mean. For sample sizes larger than 30, the lower limits for t/h and castingha
47、rdness control may be optionally taken as the lower 3 standard deviation limit or the lower 99% populationlimit of the one-sided normal distribution at 95% confidence calculated by the confidence interval method (seeA.1.5). 5.5.1 Test bar samples to confirm test bar t/h ratio conformance shall be ra
48、ndom samples. Frequency of samplingmay be specified by purchaser or determined by producer. Minimum frequency per grade shall be 1 per 8 hshift. Sample period may be any time interval or accumulation of time intervals in which the targeted meant/h of producers process control specifications is uncha
49、nged.5.5.2 Casting samples to confirm casting hardness conformance shall be random samples. Frequency ofsampling may be specified by purchaser or determined by producer. Minimum frequency shall be the leastof 5 per 8 h shift or 100% of production. Sample period may be any time interval or accumulation of timeintervals during which the targeted mean casting hardness of producers process control specifications isunchanged.5.5.3 Parts successfully established in pr
