1、 SURFACE VEHICLE RECOMMENDED PRACTICE J2329 APR2015 Issued 1997-05 Reaffirmed 2015-04 Superseding J2329 MAY1997 Categorization and Properties of Low-Carbon Automotive Sheet Steels RATIONALE J2329 has been reaffirmed to comply with the SAE five-year review policy. _ SAE Technical Standards Board Rule
2、s provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of
3、the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2015 SAE International All rights reserved. No part of this publication may be reproduced, stored
4、 in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside USA) Fax: 724-776-0790 Em
5、ail: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J2329_201504 Foreworda. CategorizationMechanical property, surface quality, and manufacturing requirements for automo
6、tive sheetsteels, together with improvements in steel manufacturing and processing techniques, have made earliermethods of categorizing sheet steel obsolete. Classification of steel quality by deoxidation process is nolonger appropriate. Uniformity of material properties is of major importance. This
7、 SAE RecommendedPractice furnishes a categorization procedure to aid in selecting low-carbon sheet steel for identified parts andfabrication processes.It is necessary for both the steel user and producer to know the mechanical properties and the range in theseproperties. There is a wide variety of p
8、arts within the automotive industry, and different levels of specificmechanical properties, e.g., rm value, n value, yield strength, and total elongation may be required for specificapplications. With the recent advent of computer simulation of the steel deformation process during diedesign, it is v
9、itally important that certain minimum levels of formability exist within a particular category orgrade of steel. It is suggested that the steel user and steel supplier consult early in the part and die designprocess to determine specific grade requirements. In the past, yield strength has been chose
10、n as a majordiscriminator of the categorization system since this property has meaning to both automotive and steelengineers, this document builds on that rationale but also addresses certain minimum elongation, n value andrm value discriminators. In this document, low-carbon sheet steel is classifi
11、ed by 5 grade levels with yieldstrength, tensile strength, elongation, rm value, and n value requirements. In addition, surface quality and/oraging characteristics are an important consideration. Thus, the categorization system is as follows:1. The first two alphabetic characters will designate hot-
12、rolled or cold-rolled method of manufacture.2. The third numeric character defines grade based on yield strength range, minimum tensile strength,minimum percent elongation, minimum rm value, and minimum n value.3. The fourth alphabetic character classifies the steel type with regards to surface qual
13、ity and/or agingcharacter.4. An optional fifth alphabetic character may restrict the carbon content to a minimum of 0.015%.b. PropertiesThe mechanical properties of the substrate (ductility, work hardening, and plastic anisotropy)determine the ability of the steel to withstand strain in various mode
14、s of forming (such as stretching and deepdrawing). Mechanical properties are important to the formability of uncoated and coated steels, both cold-rolled and hot-rolled. Compared with uncoated steel sheets, hot-dip and electroplated coated steels havedifferent characteristics which may affect automo
15、tive manufacturing operations such as stamping, welding, andpainting. Material related factors greatly influence the formability of coated sheets. Coating characteristicsalthough less important to forming than the substrate, can have a significant influence on forming because thecoating can affect m
16、etal flow over tool and die surfaces.Definition of steel sheet properties is contained in Appendix A.1. ScopeThis SAE Recommended Practice establishes mechanical property ranges for low-carbon automotivehot-rolled sheet, cold-rolled sheet, and metallic-coated sheet steels. It also contains informati
17、on that explainsthe different nomenclature used with these steels.2. References2.1 Applicable PublicationsThe following publications form a part of this specification to the extent specifiedherein. Unless otherwise indicated, the latest issue of SAE publications shall apply.2.1.1 SAE PUBLICATIONSAva
18、ilable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J416Tensile Test SpecimensSAE J863Methods for Determining Plastic Deformation in Sheet Metal StampingsSAE J1392Steel, High-Strength, Hot-Rolled Sheet and Strip, Cold-Rolled Sheet, and Coated SheetSAE J1562Selection of Galvanized
19、(Hot-Dipped and Electrodeposited) Steel Sheet2.1.2 ASTM PUBLICATIONSAvailable from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.ASTM A 370Standard Test Methods and Definitions for Mechanical Testing of Steel ProductsASTM E 8Standard Test Methods of Tension of Metallic MaterialsASTM
20、E 517Standard Test Method for Plastic Strain Ratio r for Sheet MetalASTME646Standard Test Method for Tensile Strain-Hardening Exponents (n value) of Metallic SheetMaterials2.1.3 ASM PUBLICATIONAvailable from ASM International, Attn: MSC/Book Order, P. O. Box 473, Novelty, OH44072-9901.ASM Handbook2.
21、2 Related PublicationsThe following publications are provided for information purposes only and are not arequired part of this document.2.2.1 SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J810Classifications of Common Imperfections in Sheet SteelSAE J940Gl
22、ossary of Carbon Steel Thickness and TolerancesSAE J1058Standard Sheet Steel Thickness and Tolerances2.2.2 ASTM PUBLICATIONSAvailable from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.ASTM A 366/A 366MSpecification for Steel, Sheet, Carbon, Cold-Rolled, Commercial QualityASTMA568/A5
23、68MSpecification for Steel, Sheet, Carbon, and High Strength, Low Alloy, Hot-Rolledand Cold-Rolled, General Requirements forASTMA569/A569MSpecification for Steel, Carbon (0.15 Maximum, Percent), Hot-Rolled Steel andStrip, Commercial QualityASTM A 619A/619MSpecification for Steel, Sheet, Carbon Cold-
24、Rolled Drawing QualityASTM A 620/A 620MSpecification for Steel, Sheet, Carbon, Drawing Quality, Special Killed, Cold-RolledASTM A 621/A 621MSpecification for Steel, Sheet and Strip, Carbon, Hot-Rolled, Drawing QualityASTMA 622/A622MSpecification for Steel, Sheet and Strip, Carbon, Drawing Quality, S
25、pecial Killed,Hot-Rolled_ SAE INTERNATIONAL J2329 Reaffirmed APR2015 2 of 11ASTMA642/A642MSpecification for Steel Sheet, Zinc-Coated (Galvanized by the Hot-Dip Process,Drawing Quality, Special Killed)ASTMA653/A653MSteel Sheet, Zinc Coated (Galvanized) or Zinc-Iron Alloy Coated (Galvannealed)by the H
26、ot-Dip ProcessASTM A 924/A 924MGeneral Requirements for Steel Sheet, Metallic Coated by the Hot-Dip Process2.2.3 OTHER PUBLICATIONSteel Products Manual, Sheet Steel; Iron and Steel Society Publication, January 19883. GradesThe specific grades are identified by a maximum of 5 characters. The first tw
27、o characters will beletters defining method of manufacture of steel; HR for hot rolled and CR for cold rolled. The third character willconsist of a single digit number defining the chemical and forming characteristics as specified in Tables 1through 3. The fourth character, an alphabetic character,
28、will define the type of steel as outlined in Section 4.An additional 5th suffix character, C, may be added if restriction to low-carbon steelmaking is desired by thepurchaser. The single-digit number specifies the mechanical requirements for: yield and tensile strength inMPa, elongation %, rm value,
29、 and n value.TABLE 1COLD-ROLLED STEEL SHEET, COATED AND UNCOATED, MECHANICAL PROPERTIES(1)(2)1. N/R = Not required.2. ASTM A 370, Test parameters in all directions.SAE J2329DesignationYield Strength(MPa) at 0.2%OffsetTensile Strength(MPa) MinimumTotal % Elongationin 50 mmMinimumrm value(3)Min.3. AST
30、M E 517, Parameter for r calculated at 17% strain, rm calculation by (r0 + r90 +2r45)/4. The rm value can be up to 0.2 lower for thickness greater than 1.4 mm and/or Galvanneal products.n Value(4)Min.4. ASTM E 646, n Value calculated from 10 to 20% strain or 10% to end of uniform elongation when uni
31、form elongation is less than 20%.Grade 1 N/R N/R N/R N/R N/RGrade 2 140 to 260 270 34 N/R 0.16Grade 3 140 to 205 270 38 1.5 0.18Grade 4 140 to 185 270 40 1.6 0.20Grade 5 110 to 170 270 42 1.7 0.22TABLE 2HOT-ROLLED STEEL SHEET, COATED AND UNCOATED, MECHANICAL PROPERTIES(1)(2)1. N/R = Not required.2.
32、ASTM A 370, Test parameters in all directions.SAE J2329DesignationYield Strength(MPa) at 0.2%OffsetTensile Strength(MPa) MinimumTotal % Elongationin 50 mmMinimumn Value(3)Min.3. ASTM E 646, n Value calculated from 10 to 20% strain or 10% to end of uniform elongation when uniform elongation is less t
33、han 20%.Grade 1 N/R N/R N/R N/RGrade 2 180 to 290 270 34 0.16Grade 3 180 to 240 270 38 0.18_ SAE INTERNATIONAL J2329 Reaffirmed APR2015 3 of 11Under certain circumstances particular parts may require steel properties that do not conform exactly to thespecific grades defined herein. These deviations
34、should be resolved through agreement between the steeluser and the steel producer.Cold-rolled and metallic-coated cold-rolled coated steels specified to a 180 MPa or greater minimum yieldstrength are considered high-strength steels. Hot-rolled and metallic-coated hot-rolled steels specified to a 260
35、 MPa or greater minimum yield strength areconsidered high-strength steels.Titanium, Niobium, and other alloy elements can be used in combination, if fully stabilized product is required.Stabilization elements must be reported on chemical certification.4. TypesThere are several types of cold-rolled/c
36、oated steels and hot-rolled steels that result from differences insteel manufacturing processes and automotive stamping operations. The types of steels are referred to byletter code that follows the class designation.4.1 Cold-Rolled and Metallic-Coated Cold-Rolled Sheet SteelTwo types of these steel
37、s are produced. Thesetypes are based on surface quality.4.1.1 Type E is intended for the most critical exposed applications where surface appearance is of primaryimportance. This type of steel will meet requirements for controlled surface texture, surface quality, andflatness.4.1.2 Type U is intende
38、d for unexposed applications and may also have special use where improved ductility overa temper-rolled product is desired. Type U can be produced without temper rolling; this type of steel may beexpected to exhibit coil breaks, fluting, and stretcher straining. Standard tolerances for flatness and
39、surfacetexture are not applicable. In addition, surface imperfections are more prevalent and severe than with TypeE.4.2 Hot-Rolled and Metallic-Coated Hot-Rolled Sheet SteelFour types of hot-rolled steel are available.4.2.1 Type R is an as-hot-rolled coiled product. Typically known as Hot Roll Black
40、 Band. Therefore, it has notbeen processed in any way; i.e., pickled, oiled, temper-rolled, side trimmed, rewound, or cut back toestablished thickness and width tolerances. Yield strength range classes apply only to material that hasbeen cut back to established thickness and width tolerances. Proces
41、sed coils may have had any or all of theprocessing steps listed in the previous paragraph performed subsequent to hot rolling. Ends of coils are cutback to established width and thickness tolerances.TABLE 3HOT-ROLLED AND COLD-ROLLed STEEL SHEET, LOW CARBON, CHEMICAL COMPOSITION(1)1. Ladle or Heat An
42、alysisSAE J2329DesignationCarbon %max(2)2. 0.015% Carbon minimum requirement if suffix C is used. C cannot be specified for Grade 5.ManganeseMax. %PhosphorusMax. %SulfurMax. %.AluminumMin. %Grade 1 0.13 0.60 0.035 0.035 Grade 2 0.10 0.50 0.035 0.030 0.020Grade 3 0.10 0.50 0.030 0.030 0.020Grade 4 0.
43、08 0.40 0.025 0.025 0.020Grade 5 0.02 0.30 0.025 0.025 0.020_ SAE INTERNATIONAL J2329 Reaffirmed APR2015 4 of 114.2.2 Type F has been processed and is available in coils or cut lengths. This material is susceptible to coil breaksand aging.4.2.3 Type N has been processed and is available in coils or
44、cut lengths. This material is nonaging at roomtemperature but is susceptible to coil breaks.4.2.4 Type M has been processed and is available in coils or cut lengths. This material is free from coil breaks anddoes not strain age at room temperature.Some of the product characteristics available for ea
45、ch type of hot-rolled steel are listed in Table 4.5. ExamplesAs previously discussed, categorization is made by commodity, grade, and type.CR2E: Cold-rolled sheet steel with chemical requirements of Table 3 Grade 2, minimum mechanicalproperties as specified in Table 1 Grade 2 and of critical exposed
46、 surface quality.HR3MU: Hot-rolled sheet steel with chemical requirements of Table 3 Grade 3, minimum mechanicalproperties as specified in Table 2 Grade 3, unexposed, M product characteristics as specified inTable 4.For metallic-coated sheet products, SAE J1562 is used to designate coatings of hot-d
47、ipped andelectrodeposited zinc. SAE J1562 should be referenced for full explanation of the nomenclature and productcharacteristics.CR4C EG60G60GE: Cold-rolled sheet steel with the chemical requirements of Table 3 Grade 4,minimum mechanical properties as specified in Table 1 Grade 4, critical exposed
48、 surface quality,0.015% minimum carbon, and two side electrogalvanized coated to 60 g/m2 each side.HR2M 45A45AU: Hot-rolled sheet steel with the chemical requirements of Table 3 Grade 2, minimummechanical properties as specified in Table 2 Grade 2, unexposed, M product characteristic asspecified in Table 4, two side galvannealed coated to 45 g/m2 each side.6. Sampling ProcedureWhen questions arise as
