1、 SURFACE VEHICLE RECOMMENDED PRACTICE J126 APR2015 Issued 1969-09 Reaffirmed 2015-04 Superseding J826 JUN1986 Selecting and Specifying Hot and Cold Rolled Steel Sheet and Strip RATIONALE J826 has been reaffirmed to comply with the SAE five-year review policy. _ SAE Technical Standards Board Rules pr
2、ovide 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 the
3、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 in
4、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 Email:
5、 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/J126_201504 1. ScopeThis SAE Recommended Practice outlines a procedure for selecting the proper specification forcarbon s
6、teel sheet and strip which are purchased to make an identified part. Specifications considered are:ASTM A109Steel, Carbon, Cold Rolled Strip.ASTM A569Steel, Carbon (0.15 maximum percent), Hot Rolled Sheet, Commercial Quality (HRCQ).ASTM A621Steel, Sheet, Carbon, Hot Rolled, Drawing Quality (HRDQ).AS
7、TM A622Steel, Sheet, Carbon, Hot Rolled, Drawing Quality, Special Killed (HRDQSK).ASTMA568Steel, Carbon and High-Strength Low-Alloy Hot Rolled Sheet, and Cold Rolled Sheet,General Requirements.ASTM A366Steel, Carbon, Cold Rolled Sheet, Commercial Quality (CRCQ).ASTM A619Steel, Sheet, Carbon, Cold Ro
8、lled, Drawing Quality (CRDQ).ASTM A620Steel, Sheet, Carbon, Cold Rolled, Drawing Quality, Special Killed (CRDQSK).ASTM A749MSteel, Carbon and High-Strength Low-Alloy, Hot Rolled Strip, General Requirements.ASTM A635Steel Sheet and Strip, Carbon, Hot Rolled Commercial Quality, Heavy Thickness Coils.(
9、Metric ASTM documents are designated by suffix M)It also describes how codes or symbols for specifying certain characteristics may be used in electronic dataprocessing systems. Characteristics covered are:a. Hot or cold rolled.b. Sheet or strip.c. Severity of draw (quality of steel).d. Surface condi
10、tion (finish, etc.).e. Edge condition.f. Dimensions.It is intended that other characteristics and part identification be covered by a supplement to the specification,as necessary.2. References2.1 Applicable PublicationsThe following publications form a part of the specification to the extent specifi
11、edherein. Unless otherwise indicated the latest revision of SAE publications shall apply.2.1.1 ASTM PUBLICATIONSAvailable from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.ASTM A109Steel, Carbon, Cold Rolled Strip.ASTM A569Steel, Carbon (0.15 maximum percent), Hot Rolled Sheet, Comm
12、ercial Quality (HRCQ).ASTM A621Steel, Sheet, Carbon, Hot Rolled, Drawing Quality (HRDQ).ASTM A622Steel, Sheet, Carbon, Hot Rolled, Drawing Quality, Special Killed (HRDQSK).ASTMA568Steel, Carbon and High-Strength Low-Alloy Hot Rolled Sheet, and Cold Rolled Sheet,General Requirements.ASTM A366Steel, C
13、arbon, Cold Rolled Sheet, Commercial Quality (CRCQ).ASTM A619Steel, Sheet, Carbon, Cold Rolled, Drawing Quality (CRDQ).ASTM A620Steel, Sheet, Carbon, Cold Rolled, Drawing Quality, Special Killed (CRDQSK).ASTM A749MSteel, Carbon and High-Strength Low-Alloy, Hot Rolled Strip, General Requirements.ASTM
14、 A635Steel Sheet and Strip, Carbon, Hot Rolled Commercial Quality, Heavy Thickness Coils.(Metric ASTM documents are designated by suffix M)3. ProcedureEvaluate the part to determine the requirements for characteristics A-F, as follows:3.1 A - Hot or Cold Rolled ProductNormally the finish or thicknes
15、s of the metal required for a part willdetermine whether hot-rolled or cold-rolled product should be specified. (See Table 1A, Table 1B, and Table 4.)3.2 B - Sheet or StripPrincipal factors to consider in determining whether sheet or strip should be specified are:Size of part, or more specifically,
16、size of flat steel required to develop part.Thickness of metal required for the part.Hot or cold rolled steel.Selection and specification of temper for cold rolled strip. (See Table 3A, Table 3B.)Equipment on which the metal will be handled and fabricated.Steel industry product classification by siz
17、e. (See Table 1A, Table 1B.)3.3 C - Selection of Sheet Steel for FormabilityFor Cold Rolled Carbon Sheet and Hot Rolled Carbon Sheetand Strip, three levels of formability or drawability (called quality in the steel industry) are available as indicatedin the Scope. They are commonly referred to as CQ
18、, DQ, and DQSK.The following procedure is based on a Forming Severity Index (FSI) which has been developed throughexperience in production forming of sheet metal stampings. The procedure is recommended for determiningthe quality needed for a specific part and fabrication operation.1. Form a sample o
19、r prototype part from a specimen of known quality of steel using the griddingprocedure outlined in SAE J863. (For the most accurate description of the quality of steel used for thegridded blank, the mechanical properties of a sample taken from material adjacent to the blank usedfor the gridded part
20、should be known. This can be from the same blank, or the sheet preceding orfollowing the sheet to be gridded.) If the specimen fractures, form another sample from the next betterquality of steel.2. Measure the e1 and e2 strains as described in SAE J863. (This should be done on a sample partwhich has
21、 not fractured during forming.)3. Calculate the Forming Severity Index (FSI), for the critical area or areas of the sample part, using thefollowing formulae:_ SAE INTERNATIONAL J126 Reaffirmed APR2015 2 of 11NOTEThe e2 strain is the associated strain (minor) measured perpendicular to the major strai
22、n, e1.When the e2 strain as measured on the grid in the maximum stretch area is 0 to +30%.(Eq. 1)When the e2 strain is 0 to 30% (biaxial tension compression forming).(Eq. 2)where:t = thickness of gridded panel in inches.e1 = major strain expressed as a percent (not a decimal value).e2 = minor strain
23、 expressed as a percent (not a decimal value).The sign of e2 is disregarded (an e2 of 30 is expressed as 30 in the formula).NOTE:a. The thickness t in the above formulae is only a correction factor for calculation of the FSI. Materialformability may not be dependent on the sheet metal thickness.b. I
24、f t is expressed in millimeters, the multiplier will be 13.8 instead of 350.c. The reliability of the equations for stock over 0.125 in or 3 mm has not been established.d. The constant 15 in the above formulae can be modified by mutual consent of the supplier and userto provide the desired degree of
25、 risk of breakage. A constant of 15 approximates a safety factor often percentage of strain points for die, lubricant, press, and material variance of e1 strain (majorstrain). A constant of 20 gives a safety factor of 5, and a constant of 10 gives a safety factor of 15.4. Select the quality of steel
26、 sheet needed for the part from Table 2. When a change in material isindicated by Table 2, the selection should be verified using the new quality of sheet metal to formanother sample part.5. After a sufficient production history has been obtained through the use of the SAE RecommendedPractice J424,
27、Determination of Breakage Allowance for Steel Sheets, the quality of steel being usedshould be reviewed. For a given part an unusually high scrap rate indicates either a tool, lubricant, ormaterial quality selection problem. If material quality is found to be the problem, upgrading should beconsider
28、ed. Conversely, an unusually low scrap rate indicates a less expensive quality should beconsidered. SAE Recommended Practice J863 should be followed to determine the most beneficialmaterial change.EXAMPLEIn the case of 0.080 in or 2.00 mm thick sheet steel with e1 strain of 33% and e2 strain of +10%
29、,the Forming Severity Index (FSI) would be:(Eq. 3)(Eq. 4)FSI0.6e2 15350t+()e1=FSI1.5e2 15350t+()e1=FSI0.610()in()153500.080()+33FSI16=FSI0.610()mm()1513.82.0()+33FSI16=_ SAE INTERNATIONAL J126 Reaffirmed APR2015 3 of 11If the gridded panel was CRCQ steel, the FSI indicates the selection of a lower q
30、uality steel such asHRDQ (A621). Note that in cases such as this where the FSI is greater than +6 there are other factorsthan material which should be investigated to obtain the most economical production.If the gridded panel was HRDQ, the indicated selection would be HRCQ (A569).In the case of 0.03
31、6 in or 0.9 mm thick stock with an e1 strain of 55% and an e2 strain of 15%, the FSIwould be:(Eq. 5)(Eq. 6)If the gridded panel was CRCQ and trouble was being encountered in forming production parts, theindicated selection would be to upgrade to CRDQ (A619). If the gridded panel was CRDQ, theindicat
32、ed selection would be to upgrade to CRDQSK (A620) and if the panel was CRDQSK someother changes may be required in the forming operations or in the design of the part (comments inTable 2).3.4 D - Surface Condition (Finish, etc.)Consider any surface conditions required for the part. Consult Table 4fo
33、r a description of surfaces applicable to the product selected in A, B, and C above. Designate surface, finish,coating, etc. by symbol shown.3.5 E - Edge ConditionConsider any necessary edge conditions required for the part. Consult Table 5 for adescription of edges applicable to the product selecte
34、d in A, B, and C above. Designate the required edgecondition by the symbol shown.3.6 F - DimensionsConsider all dimensions required for the part.Refer to ASTM A568 for thickness tolerance tables.Designate dimensions in the following order: thickness, width, and length. (Note: Use the symbol C for le
35、ngthof material purchased in coil form.) When the measuring unit is inches, all fractions thereof shall be expressedas decimals and not as common fractions (for example, 1.25 in, not 1-1/4 in). State the thickness to threedecimal places and width and length to two decimal places.When metric units ar
36、e used for dimensions, the thickness, width, and length should be expressed inmillimeters. State thickness to one decimal place and width and length in whole numbers.EXAMPLEFor cut length: 0.035 x 36.25 x 84.75 (in) 0.9 x 900 x 2153 (mm)For coil length: 0.047 x 47.37 x C (in) 1.2 x 1200 x C(mm)(Thes
37、e units are not intended to indicate conversion of inch to metric units.)FSI1.515()in()153500.036()+55FSI 5=FSI1.515()mm()1513.80.09()+55FSI 5=_ SAE INTERNATIONAL J126 Reaffirmed APR2015 4 of 113.7 GFor a more complete explanation of industry nomenclature for Cold Rolled or Hot Rolled Steel Sheet, t
38、heAISI Steel Customer Communication Handbooks are recommended.TABLE 1ASTEEL SHEET OR STRIP PRODUCT CLASSIFICATION BY SIZE, METRIC UNITSProduct Thickness, mm Width, mm Other Limitations Specification Symbol (ASTM No.)Hot Rolled Sheet 1.26.0 Over 300 thru 1200 Coils and Cut Lengths A 569M, A 621M, or
39、A 622M1.24.5 Over 12006.012.5 Over 300 thru 1200 Coils Only A 635M4.512.5 Over 1200 thru 1800Hot Rolled Strip 1.25.0 Thru 200 Coils and Cut Lengths A 569M, A 621M, or A 622M1.26.0 Over 200 thru 3006.012.5 Over 200 thru 300 Coils Only A 635MCold Rolled Sheet 0.352.0 Over 50 thru 300 See Note 1 A 366M
40、, A 619M, or A 620M0.35 and Over Over 300 See Note 2Cold Rolled Strip Thru 6.0 Over 12 thru 600 See Note 3 A 109MNOTE 1Cold rolled sheet, coils, and cut lengths, slit from wider coils with cut edge (only), thicknesses 0.352.0 mm and carbon of 0.25% max by cast analysis.NOTE 2When no special edge or
41、finish (other than matte, commercial bright, or luster) is required and/or single strand rolling of widths under 600 mm is not required.NOTE 3Widths 50300 mm with thicknesses of 0.352.0 mm are classified as “sheet“ when slit from wider coils, have a cut edge only, and carbon of 0.25% max by cast ana
42、lysis.TABLE 1BSTEEL SHEET OR STRIP PRODUCT CLASSIFICATION BY SIZE, INCH-POUND UNITSProduct Thickness, in Width, in Other Limitations Specification Symbol (ASTM No.)Hot Rolled Sheet 0.045 thru 0.230 Over 12 thru 48 Coils and Cut Lengths A 569, A 621, or A 6220.045 thru 0.180 Over 480.230 thru 0.500 O
43、ver 12 thru 48 Coils Only A 6350.180 thru 0.500 Over 48 thru 72Hot Rolled Strip 0.045 thru 0.203 Thru 6 Coils and Cut Lengths A 569, A 621, or A 6220.045 thru 0.229 Over 6 thru 120.230 thru 0.500 Over 8 thru 12 Coils Only A 635Cold Rolled Sheet 0.014 thru 0.082 Over 2 thru 12 See Note 1 A 366, A 619
44、, or A 620Over 0.014 Over 12 See Note 2Cold Rolled Strip Thru 0.250 Over 0.50 thru 23.9 See Note 3 A 109NOTE 1Cold rolled sheet, coils, and cut lengths, slit from wider coils with cut edge (only), thicknesses 0.0140.082 in and carbon of 0.25% max by cast analysis.NOTE 2When no special edge or finish
45、 (other than matte, commercial bright, or luster) is required and/or single strand rolling of widths under 24 in is not required.NOTE 3Widths 212 in with thicknesses of 0.0140.082 in are classified as “sheet“ when slit from wider coils, have a cut edge only, and carbon of 0.25% max by cast analysis.
46、_ SAE INTERNATIONAL J126 Reaffirmed APR2015 5 of 11TABLE 2SELECTION OF QUALITY OF STEEL SHEET AND STRIP BASED ON THE FORMING SEVERITY INDEX (FSI)Quality of Steel Usedfor the GriddedSample PanelQuality Suggested When the Forming Severity Indexis Within the Range Given Below20 to 11 10 to 1 0 to +5 +6
47、 and GreaterDQSK DQSK (1) (2)1. This indicates too much is being expected of the sheet metal, a part redesign or breakdown into separate components may be necessary in addition to the factors below.2. This represents a part which is difficult to form, other factors, such as tools, design, drawing compound application, blank development, etc., should be considered to provide an adequate Forming Severity Index because further upgrading is not possible. (Premium quality grades of steel with a high plastic strain ratio (rm) values may be necessary if th
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