1、 ISO 2016 Cold-reduced steel sheet of high tensile strength and low yield point with improved formability Tles en acier lamines froid haute rsistance la traction et faible limite dlasticit, et aptitude au formage accrue INTERNATIONAL STANDARD ISO 14590 Third edition 2016-08-15 Reference number ISO 1
2、4590:2016(E) ISO 14590:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, in
3、cluding photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerlan
4、d Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.org ISO 14590:2016(E)Foreword iv 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Dimensions . 2 5 Conditions of manufacture 3 5.1 Steelmaking . 3 5.2 Chemical composition 3 5.3 Chemical analysis 4 5.3.1 Heat an
5、alysis 4 5.3.2 Product analysis . 4 5.4 Mechanical properties 4 5.5 Application . 6 5.6 Weldability 6 5.7 Surface condition 6 5.8 Surface finish 7 5.9 Oiling 7 5.10 Dimensional and shape tolerances 7 6 Sampling Tensile test 7 7 Test methods Tensile test . 7 8 Retests . 7 8.1 Machining and flaws. 7 8
6、.2 Elongation . 7 8.3 Additional tests . 7 9 Resubmission . 8 10 Workmanship 8 11 Inspection and acceptance . 8 12 Coil size . 8 13 Marking 8 14 Information to be supplied by the purchaser. 9 Annex A (normative) Bake hardening test method10 Bibliography .12 ISO 2016 All rights reserved iii Contents
7、Page ISO 14590:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in
8、a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commissi
9、on (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents shou
10、ld be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for id
11、entifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the conv
12、enience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformit y assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) se
13、e the following URL: www.iso.org/iso/foreword.html. The committee responsible for this document is ISO/TC 17, Steel, Subcommittee SC 12, Continuous mill flat rolled products. This third edition cancels and replaces the second edition (ISO 14590:2005), which has been technically revised.iv ISO 2016 A
14、ll rights reserved INTERNATIONAL ST ANDARD ISO 14590:2016(E) Cold-reduced steel sheet of high tensile strength and low yield point with improved formability 1 Scope This International Standard applies to cold-reduced steel sheet of two types that are commercially available in the world. Type 1 repre
15、sents steels that are produced to mechanical properties only and Type 2 represents steels that are produced to both chemical and mechanical properties. Bake hardening steels are included in both types. This International Standard does not cover steels designated as commercial quality or drawing qual
16、ities (covered in ISO 3574), steels of structural quality (covered in ISO 4997) or steels of higher strength with improved formability (covered in ISO 13887). 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for it
17、s application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 6892-1, Metallic materials Tensile testing Part 1: Method of test at room temperature ISO 16162, Cold-rolled steel sheet
18、products Dimensional and shape tolerances 3 T erms a nd definiti ons For the purposes of this document, the following terms and definitions apply. 3.1 bake hardenable steel highly formable steel that, subsequent to cold working, has been subjected to a low-temperature heat treatment, such as that us
19、ed for paint baking (170 C to 200 C), in order to effect a significant increase in its yield strength, primarily due to carbon ageing 3.2 cold-reduced steel sheet product obtained from hot-rolled descaled steel sheet by cold-reducing to the required sheet thickness followed by annealing to recrystal
20、lize the grain structure 3.3 dual-phase steel steel whose thermal processing has resulted in a multi-phase structure that includes one or more low- temperature transformation products, thus providing for improved formability at higher strength levels 3.4 skin pass light cold-rolling of the product N
21、ote 1 to entry: The purpose of the skin passing is one or more of the following: to minimize the appearance of coil breaks, stretcher strains and fluting; to control the shape; and to obtain the required surface finish. Note 2 to entry: Some increase in hardness and some decrease of ductility will r
22、esult from skin passing. ISO 2016 All rights reserved 1 ISO 14590:2016(E) 3.5 ageing change in steel properties with the passage of time Note 1 to entry: Ageing may result in a change in yield strength and a corresponding decrease in ductility during storage. Ageing always has a negative effect on f
23、ormability. The redevelopment of a definite yield point phenomenon as a result of ageing can result in a renewed susceptibility to surface imperfections, such as stretcher strain marks (Lders Lines) and fluting when the steel is formed. To avoid these adverse outcomes, it is essential that the perio
24、d between final processing at the producing mill and fabrication be kept to a minimum. Rotation of stock, by using the oldest material first, is important. Effective roller levelling immediately prior to fabrication can achieve reasonable freedom from stretcher strain marks. 3.6 lot up to a specifie
25、d quantity of steel sheet of the same designation rolled to the same thickness and grade 3.7 Type 1 cold-reduced steel sheet (3.2) specified to mechanical properties only 3.8 Type 2 cold-reduced steel sheet (3.2) specified to both mechanical properties and chemical composition 3.9 preliminary strain
26、 load F WH load (kgf or N) of work hardening reached when the preliminary strain elongation specified in the tensile test is reached Note 1 to entry: Preliminary strain elongation herein shall be 2 %. Note 2 to entry: to entry: Refer to Figure A.2. 3.10 strain ageing yield load F SA load (kgf or N)
27、at yielding measured during the tensile testing of the specimen after it has been strained and heat-treated at 170 C for 20 min Note 1 to entry: Refer to Figure A.1. 3.11 BH amount O BH value (kgf/mm 2or N/mm 2 ) obtained by dividing the value (kgf or N) derived by subtracting the preliminary strain
28、 load, F WH , from the strain ageing yield load, F SA , of the test piece parallel portion original area (mm 2 ) before the preliminary strain 4 Dimensions Cold-reduced steel sheet of high tensile strength and low yield point with improved formability is produced in thicknesses from 0,25 mm to 3,2 m
29、m and in widths of 600 mm and over in coils and cut lengths. Product less than 600 mm wide, slit from wide sheet, will be considered as sheet.2 ISO 2016 All rights reserved ISO 14590:2016(E) 5 Conditions of manufacture 5.1 Steelmaking Unless otherwise agreed upon by the interested parties, the proce
30、sses used in making the steel and in manufacturing cold-reduced steel sheet are left to the discretion of the manufacturer. On request, the purchaser shall be informed of the steelmaking process being used. 5.2 Chemical composition The chemical composition (heat analysis) shall conform to the requir
31、ements given in Tables 1 and 2. Table 1 Chemical composition for Type 2 (heat analysis) Mass fractions in percent Grade a C max. Si max. Mn max. P max. S max. SS220 0,10 0,50 1,00 0,100 0,030 SS260 0,10 0,50 1,50 0,120 0,030 SS300 0,15 0,50 1,50 0,140 0,030 DP250 0,10 0,70 2,00 0,030 0,030 DP280 0,1
32、2 0,70 2,50 0,030 0,030 DP300 0,14 1,40 2,00 0,080 0,030 DP350 0,14 1,40 2,50 0,100 0,030 DP400 0,18 1,40 2,50 0,030 0,030 DP600 0,20 1,40 3,00 0,030 0,030 BH180 0,04 0,50 0,70 0,060 0,030 BH220 0,08 0,50 0,70 0,080 0,030 BH260 0,08 0,50 0,70 0,100 0,030 BH300 0,10 0,50 0,70 0,120 0,030 NOTE Micro-a
33、lloying elements can be added. aSS = structural steel;DP = dual phase;BH = bake hardening. Table 2 Limits on additional chemical elements for Type 2 Mass fractions in percent Element Cu amax. Ni amax. Cr a,bmax. Mo a,bmax. Nb cmax. V cmax. Ti cmax. Heat analysis 0,20 0,20 0,15 0,06 0,008 0,008 0,008
34、 Product analysis 0,23 0,23 0,19 0,07 0,018 0,018 0,018 NOTE Each of the elements listed in this table shall be included in the report of the heat analysis. When the amount of copper, nickel, chromium or molybdenum present is less than 0,02 %, the analysis may be reported as 0,02 %. aThe sum of copp
35、er, nickel, chromium and molybdenum shall not exceed 0,50 % on heat analysis. When one or more of these elements are specified, the sum does not apply; in which case, only the individual limits on the remaining elements apply. bThe sum of chromium and molybdenum shall not exceed 0,16 % on heat analy
36、sis. When one or more of these elements are specified, the sum does not apply; in which case, only the individual limits on the remaining elements apply. cHeat analysis greater than 0,008 % may be supplied after agreement between the producer and purchaser. ISO 2016 All rights reserved 3 ISO 14590:2
37、016(E) 5.3 Chemical analysis 5.3.1 Heat analysis An analysis of each heat of steel shall be made by the manufacturer to determine compliance with the requirements of Tables 1 and 2. On request, a report of the heat analysis shall be made available to the purchaser or the purchasers representative. E
38、ach of the elements listed in Tables 1 and 2 shall be included in the report of the heat analysis. When the amount of copper, nickel, chromium or molybdenum present is less than 0,02 %, the analysis may be reported as “0,15 to 0,40 0,03 0,04 Si 0,30 to 0,60 0,60 0,05 0,06 Mn 0,60 to 1,15 1,15 to 1,7
39、0 1,70 0,04 0,05 Subject to negotiation P 0,04 0,04 0,01 Not applicable S 0,06 0,01 NOTE 1 This table applies to Type 2 Grades SS, DP and BH. NOTE 2 The above maximum tolerance is the allowable excess over the specified requirement and not the heat analysis. For example, for Grade DP350, the followi
40、ng product analysis values are within these tolerances: C 0,17; Mn 1,04; P not applicable; S 0,04 and Si 0,55. 5.4 Mechanical properties Type 1 and Type 2 steels shall satisfy the mechanical properties shown, respectively, in Tables 4 and 5 when they are determined in accordance with the requirement
41、s of Clauses 6 and 7. On request, a report of the mechanical properties shall be made to the purchaser. NOTE Prolonged storage of the sheet can result in ageing, leading to an adverse effect on formability.4 ISO 2016 All rights reserved ISO 14590:2016(E) Table 4 Mechanical properties for Type 1 Grad
42、e a R eL bN/mm 2 , min. O BH cN/mm 2 , min. R m dN/mm 2 , min. A min, % e L o= 50 mm L o= 80 mm 175YL 175 340 31 29 205YL 205 370 29 27 235YL 235 390 27 25 265YL 265 440 23 21 295YL 295 490 21 19 325YL 325 540 18 17 355YL 355 590 15 14 225YY 225 490 22 20 245YY 245 540 19 18 265YY 265 590 16 15 365Y
43、Y 365 780 12 11 490YY 490 980 5 4 185YH 185 30 340 31 29 NOTE 1 MPa = 1 N/mm 2 . aYL = forming/drawing use;YY = dual phase;YH = bake hardening. bR eL= lower yield strength. cO BH= see 3.11. dR m= tensile strength. eA = percentage elongation after fracture. ISO 2016 All rights reserved 5 ISO 14590:20
44、16(E) Table 5 Mechanical properties for Type 2 Grade a R eL bMPa, min. O BH cMPa, min. R m dMPa, min. A min, % e,fL o= 80 mm SS220 220 320 30 SS260 260 360 28 SS300 300 400 26 DP250 250 400 26 DP280 280 600 20 DP300 300 400 26 DP350 350 600 16 DP400 400 800 8 DP600 600 1 000 5 BH180 180 300 32 BH220
45、 220 30 320 30 BH260 260 30 360 28 BH300 300 30 400 26 NOTE 1 1 MPa = 1 N/mm 2 . NOTE 2 Micro-alloying elements can be added. NOTE 3 For DP and BH steels, less than 0,7 mm thickness, reduce minimum R eLby 2 %. NOTE 4 When yield phenomenon in not obvious, use Rp 0,2 % in place of R eL . aSS = structu
46、ral steel;DP = dual phase;BH = bake hardening. bR eL= lower yield strength. cO BH= see 3.11. dR m= tensile strength. eA = percentage elongation after fracture. fL o= original gauge length of test piece. 5.5 Application It is desirable that the specified product be identified for fabrication by name
47、of the part or by intended application. Proper identification of the part may include visual examination, prints or description, or a combination of these. 5.6 Weldability This product is normally suitable for welding when appropriate welding conditions are selected. NOTE 1 As the carbon content inc
48、reases above 0,15 %, spot welding becomes increasingly difficult. NOTE 2 Because the heat of welding might significantly lower the strength of Grade 490 YY, this grade is not recommended for welding. 5.7 Surface condition The condition of the surface of cold-reduced steel sheet is not required to be
49、 the same for unexposed parts as it is for exposed parts.6 ISO 2016 All rights reserved ISO 14590:2016(E) Surface condition of sheet for unexposed parts may contain pores, some slight pitting, small marks, light scratches, and a light discoloration. The surface of sheet for exposed parts shall be reasonably free of these conditions. Unless otherwise agreed, only one side is inspected. 5.8 Surfac e finish 5.8.1 Cold-reduced steel sheet is normally produced in a matte f
