1、Metallic materials Sheet and strip Method for springback evaluation in stretch bendingBS ISO 24213:2017BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06 ISO 2017Metallic materials Sheet and strip Method for springback evaluation in stretch bendingMatriaux mtalliques T
2、les et bandes Mthode dvaluation du retour lastique lors dun cintrage sous tractionINTERNATIONAL STANDARDISO24213Second edition2017-07Reference numberISO 24213:2017(E)National forewordThis British Standard is the UK implementation of ISO 24213:2017. It supersedes BS ISO 24213:2008 , which is withdraw
3、n.The UK participation in its preparation was entrusted to Technical Committee ISE/101/2, Ductility testing.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users
4、 are responsible for its correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017ISBN 978 0 580 96328 5ICS 77.040.10Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of
5、the Standards Policy and Strategy Committee on 30 June 2017.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS ISO 24213:2017 ISO 2017Metallic materials Sheet and strip Method for springback evaluation in stretch bendingMatriaux mtalliques Tles et bandes Mthode dvalua
6、tion du retour lastique lors dun cintrage sous tractionINTERNATIONAL STANDARDISO24213Second edition2017-07Reference numberISO 24213:2017(E)BS ISO 24213:2017ISO 24213:2017(E)ii ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in SwitzerlandAll rights reserved. Unless other
7、wise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address b
8、elow or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 24213:2017ISO 24213:2017(E)ii ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUMENT
9、 ISO 2017, Published in SwitzerlandAll 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, including photocopying, or posting on the internet or an intranet, without prior written perm
10、ission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgISO 24213:2017(E)Foreword
11、 ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols and designations 35 Principle 36 Test apparatus . 37 Test piece 58 Procedure. 59 Test report . 6Annex A (normative) Method for calculating blank holding pressure . 7Annex B (normative) Method for calculating nom
12、inal tensile stress . 9Annex C (normative) Device for determining radius of curvature using a dial gauge .10Bibliography .11 ISO 2017 All rights reserved iiiContents PageBS ISO 24213:2017ISO 24213:2017(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of na
13、tional standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. Intern
14、ational organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those inten
15、ded 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 should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www
16、.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 identifying any or all such patent rights. Details of any patent rights identified during the development of the document
17、 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 convenience of users and does not constitute an endorsement.For an explanation on the voluntary nature of standards, the
18、meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www .iso .org/ iso/ foreword .html.This document was prepared b
19、y Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee SC 2, Ductility testing.This second edition cancels and replaces the first edition (ISO 24213:2008), which has been technically revised.The main changes compared to the previous edition are: the Normative references has bee
20、n updated; Clause 7 c) and Clause 9 a) have been revised to specify the test piece more clearly; In Figure 2 b), a label to the test piece has been added; Clause 8 d) has been revised because the use of dial gauge is one of the methods for determining the radius of curvature; the Bibliography has be
21、en updated.iv ISO 2017 All rights reservedBS ISO 24213:2017ISO 24213:2017(E)ForewordISO (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 t
22、echnical committees. Each member body interested in 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 clos
23、ely with the International Electrotechnical Commission (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 n
24、eeded for the different types of ISO documents should 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 pa
25、tent rights. ISO shall not be held responsible for identifying 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
26、used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to t
27、he World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www .iso .org/ iso/ foreword .html.This document was prepared by Technical Committee ISO/TC 164, Mechanical testing of metals, Subcommittee SC 2, Ductility testing.This second edition cancels
28、 and replaces the first edition (ISO 24213:2008), which has been technically revised.The main changes compared to the previous edition are: the Normative references has been updated; Clause 7 c) and Clause 9 a) have been revised to specify the test piece more clearly; In Figure 2 b), a label to the
29、test piece has been added; Clause 8 d) has been revised because the use of dial gauge is one of the methods for determining the radius of curvature; the Bibliography has been updated.iv ISO 2017 All rights reserved ISO 24213:2017(E)IntroductionThis document has been established to evaluate the amoun
30、t of springback occurring in metallic sheets deformed by stretch bending. It may be used for specifying a material, directly controlling a forming operation, designing dies, or calibrating finite element programs.In metallic sheet forming processes, the geometry of the formed parts may deviate from
31、the design geometry after the parts are removed from the dies due to elastic recovery. This phenomenon is referred to as springback. ISO 2017 All rights reserved vBS ISO 24213:2017BS ISO 24213:2017Metallic materials Sheet and strip Method for springback evaluation in stretch bending1 ScopeThis docum
32、ent specifies a method for evaluating the amount of springback of sheets of metallic materials known to exhibit large amounts of springback subjected to plane-strain stretch bending, which is a typical deformation mode generated in press-formed panels. By using this method, the amount of springback
33、under stretch bending is evaluated accurately and quantitatively12.2 Normative referencesThe following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated re
34、ferences, the latest edition of the referenced document (including any amendments) applies.ISO 80000-1, Quantities and units Part 1: General3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.ISO and IEC maintain terminological databases for use in sta
35、ndardization at the following addresses: IEC Electropedia: available at h t t p :/ www .electropedia .org/ ISO Online browsing platform: available at h t t p :/ www .iso .org/ obp3.1curvaturereciprocal of the radius of curvature, r, determined at the centre of a stretch-bent specimen on the inner su
36、rface in the longitudinal direction =1r3.2amount of springbackrelative change in curvature of a test piece under force and after removal of the force shown in Figure 1=rrrINTERNATIONAL STANDARD ISO 24213:2017(E) ISO 2017 All rights reserved 1BS ISO 24213:2017ISO 24213:2017(E)a) Under force b) After
37、removal of the forceFigure 1 Radius of curvature of a test piece under force and after removal of the force3.3stretch bendingmethod of bending a test piece under tension3.4blank holding pressureforce applied on the test piece in the direction of its thickness, divided by the surface area of the test
38、 piece contacting the die3.5nominal tensile stresstensile force per unit cross-sectional area of the test piece 2 ISO 2017 All rights reservedBS ISO 24213:2017ISO 24213:2017(E)a) Under force b) After removal of the forceFigure 1 Radius of curvature of a test piece under force and after removal of th
39、e force3.3stretch bendingmethod of bending a test piece under tension3.4blank holding pressureforce applied on the test piece in the direction of its thickness, divided by the surface area of the test piece contacting the die3.5nominal tensile stresstensile force per unit cross-sectional area of the
40、 test piece 2 ISO 2017 All rights reserved ISO 24213:2017(E)4 Symbols and designationsThe symbols used in this document and the corresponding designations are given in Table 1.Table 1 Symbols and corresponding designationsSymbol Designation Unita Thickness of test piece mmb Width of test piece mmFhB
41、lank holding force Nh Amount of punch penetration mmFpPunch force Np Blank holding pressure MPaRpPunch radius mmr Radius of curvature of the inner surface of the test piece under force mmr Radius of curvature of the inner surface of the test piece after removal of the force mmrdDie profile radius mm
42、S Total surface area of test piece in contact with dies mm2T Nominal tensile stress applied to test piece MPaW Distance between dies mmw Width of the base of a dial gauge for measuring the curvature of the test piece after removal of the force (see Annex C).mmx Measured value by a dial gauge for mea
43、suring the curvature of the test piece after removal of the force (length of AD in Figure C.1)mm Curvature of the inner surface of the test piece under force (= r1) mm1 Curvature of the inner surface of the test piece after removal of the force = (r)1 mm1 Amount of springback 2 Spread angle of test
44、piece around punch rad5 PrincipleThis test is a method for evaluating the springback of a metal sheet using a stretch-bending method. The amount of springback is determined as the change in curvatures of a test piece under force and after removal of the force (see formulae in 3.1 and 3.2). The nomin
45、al tensile stress applied to the test piece is determined using the measured value of punch penetration and punch force (see Annex B).6 Test apparatusThe test apparatus is described below.6.1 Stretch-bending testing device for springback evaluation. An example of the stretch-bending device used in t
46、he test is shown in Figure 2. The radius of the semi-cylindrical punch shall be (100 1) mm. However, the radius of the punch tip and its tolerance may be determined by agreement between the parties involved.6.2 Device for determining the radius of curvature of a test piece. The principle for determi
47、ning the radius of curvature with a dial gauge is shown in Annex C, in which a dial gauge with an accuracy of 0,001 mm shall be employed. The use of optical micrometers or other non-contacting length probes is also recommended. ISO 2017 All rights reserved 3BS ISO 24213:2017ISO 24213:2017(E)Dimensio
48、ns in millimetresa) Test apparatus b) Tool setupKey1 load cell2 blank holding force3 die top plate4 die5 blank holder6 punch (R100)7 die bottom plate8 draw beads9 test pieceFigure 2 Example of stretch-bending test apparatus for springback evaluation4 ISO 2017 All rights reservedBS ISO 24213:2017ISO
49、24213:2017(E)Dimensions in millimetresa) Test apparatus b) Tool setupKey1 load cell2 blank holding force3 die top plate4 die5 blank holder6 punch (R100)7 die bottom plate8 draw beads9 test pieceFigure 2 Example of stretch-bending test apparatus for springback evaluation4 ISO 2017 All rights reserved ISO 24213:2017(E)7 Test pieceThe test piece used for the test shall be as follows.a) The test piece shall be rectangular in shape,
