1、July 2016 English price group 9No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 77.040.10!%XLC“2534132www.din.deDIN
2、EN ISO 7438Metallic materials Bend test (ISO 7438:2016);English version EN ISO 7438:2016,English translation of DIN EN ISO 7438:2016-07Metallische Werkstoffe Biegeversuch (ISO 7438:2016);Englische Fassung EN ISO 7438:2016,Englische bersetzung von DIN EN ISO 7438:2016-07Matriaux mtalliques Essai de p
3、liage (ISO 7438:2016);Version anglaise EN ISO 7438:2016,Traduction anglaise de DIN EN ISO 7438:2016-07SupersedesDIN EN ISO 7438:2012-03www.beuth.deDocument comprises 14 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.06.16 DIN
4、EN ISO 7438:2016-07 2 A comma is used as the decimal marker. National foreword This document (EN ISO 7438:2016) has been prepared by Technical Committee ISO/TC 164 “Mechanical testing of metals”, Subcommittee SC 2 “Ductility testing” (Secretariat: JISC, Japan) in collaboration with Technical Committ
5、ee ECISS/TC 101 “Test methods for steel (other than chemical analysis)” (Secretariat: AFNOR, France) in accordance with the agreement on technical cooperation between ISO and CEN (Vienna Agreement). The responsible German body involved in its preparation was DIN-Normenausschuss Materialprfung (DIN S
6、tandards Committee Materials Testing), Working Committee NA 062-01-42 AA Zug- und Duktilittsprfung fr Metalle. Attention is drawn to the fact that the “bend test” as stated in the title of the original ISO document is, however, a technological bending test (in the withdrawn German national Standard
7、DIN 5011 also referred to as “bend-over test”). Depending on the method used, either the term “Biegestempel” (see 4.1.a) and 4.1b) or the term “Biegedorn” (bending device with a clamp, see 4.1.c) is used in the German version. In the English version, the term “former” is used throughout for all thre
8、e methods. For the use of the bending device with two supports and a former (see 4.1a) and Figure 1), the following should be noted: The information regarding a possible clamping and stretch forming of the test piece in the case of a distance between the supports ( + 2 ), given in the National forew
9、ord to DIN EN ISO 7438:2012-03, has been adopted in this standard in the form of a NOTE to Subclause 4.2.2. Furthermore, it should be noted that in case of ( + 2 ) a meaningful interpretation of results as regards the angle of bend or any cracks in the test piece is not possible. It cannot be assume
10、d with certainty that the appearance of cracks in the test piece is the result of a force reduction during the bend test, since a force reduction can also be caused by the geometry of the test piece. Amendments This standard differs from DIN EN ISO 7438:2012-03 as follows: a) the information regardi
11、ng a possible clamping and stretch forming of the test piece in the case of a distance between the supports ( + 2 ), given in the National foreword to DIN EN ISO 7438:2012-03, has been adopted in this standard in the form of a NOTE to Subclause 4.2.2; b) Figure 3 has been revised (test arrangement w
12、ith test piece prior to testing and after the test); c) Figure A.1 and formula (A.4) have been revised; d) the standard has been editorially revised. Previous editions DIN 1605-4: 1936-02 DIN 50111: 1977-11, 1987-09 DIN EN ISO 7438: 2000-07, 2005-10, 2012-03 EUROPEAN STANDARD NORME EUROPENNE EUROPIS
13、CHE NORM EN ISO 7438 January 2016 ICS 77.040.10 Supersedes EN ISO 7438:2005English Version Metallic materials - Bend test (ISO 7438:2016) Matriaux mtalliques - Essai de pliage(ISO 7438:2016) Metallische Werkstoffe - Biegeversuch(ISO 7438:2016) This European Standard was approved by CEN on 21 Novembe
14、r 2015. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtai
15、ned on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN
16、-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland,
17、 Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre:
18、Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 7438:2016 EEuropean foreword .31 Scope . 52 Symbols and designations 53 Principle 54 Test equipment. 64.1 General . 64.2 Bending device with
19、 supports and a former . 74.3 Bending device with a V-block. 74.4 Bending device with a clamp 85 Test piece 85.1 General . 85.2 Edges of rectangular test pieces. 85.3 Width of the test piece 85.4 Thickness of the test piece 85.5 Test pieces from forgings, castings and semi-finished products . 95.6 A
20、greement for test pieces of greater thickness and width . 95.7 Length of the test piece 96 Procedure. 97 Interpretation of results 118 Test report 11Annex A (informative) Determination of the bend angle from the measurement of the displacement of the former 12Contents PageDIN EN ISO 7438:2016-07 EN
21、ISO 7438:2016 (E)2Foreword 4European foreword This document (EN ISO 7438:2016) has been prepared by Technical Committee ISO/TC 164 “Mechanical testing of metals” in collaboration with Technical Committee ECISS/TC 101 “Test methods for steel (other than chemical analysis)” the secretariat of which is
22、 held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July 2016, and conflicting national standards shall be withdrawn at the latest by July 2016. Attention is drawn to the possibility t
23、hat some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 7438:2005. According to the CEN-CENELEC Internal Regulations, the national standards organiza
24、tions of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Mal
25、ta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 7438:2016 has been approved by CEN as EN ISO 7438:2016 without any modification. DIN EN ISO 7438:2016-07 EN ISO 7438:2016 (E)3 Forewor
26、dISO (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 a subject for which a technical
27、 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 Commission (IEC) on all matters of elec
28、trotechnical 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 should be noted. This document was d
29、rafted 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 identifying any or all such patent
30、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 convenience of users and does not cons
31、titute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe co
32、mmittee responsible for this document is ISO/TC 164, Mechanical testing of metals, Subcommittee SC 2, Ductility testing.This third edition cancels and replaces the second edition (ISO 7438:2005), which has been technically revised. The following changes have been made: Figure 3 has been revised; a n
33、ote has been added in 4.2.2; Formula (A.4) and Figure A.1 have been revised.DIN EN ISO 7438:2016-07 EN ISO 7438:2016 (E)4 1 ScopeThis International Standard specifies a method for determining the ability of metallic materials to undergo plastic deformation in bending.This International Standard appl
34、ies to test pieces taken from metallic products, as specified in the relevant product standard. It is not applicable to certain materials or products, for example tubes in full section or welded joints, for which other standards exist.2 Symbols and designationsSymbols and designations used in the be
35、nd test are shown in Figures 1 and 2 and specified in Table 1.Table 1 Symbols and designationsSymbol Designation Unita Thickness or diameter of test piece (or diameter of the inscribed circle for pieces of polygonal cross-section)mmb Width of the test piece mmL Length of the test piece mml Distance
36、between supports mmD Diameter of the former mm Angle of bend degreesr Internal radius of bend portion of test piece after bending mmf Displacement of the former mmc Distance between the plane including the horizontal axis of sup-ports and the central axis of the rounded portion of the former before
37、testmmp Distance between the vertical planes including the central axis of each support and the vertical plane including the central axis of the formermmR Radius of the supports mm3 PrincipleThe bend test consists of submitting a test piece of round, square, rectangular or polygonal cross-section to
38、 plastic deformation by bending, without changing the direction of loading, until a specified angle of bend is reached.The axes of two legs of the test piece remain in a plane perpendicular to the axis of bending. In the case of a 180 bend, the two lateral surfaces may, depending on the requirements
39、 of the product standard, lie flat against each other or may be parallel at a specified distance, an insert being used to control this distance.DIN EN ISO 7438:2016-07 EN ISO 7438:2016 (E)5 4 Test equipment4.1 GeneralThe bend test shall be carried out in testing machines or presses equipped with the
40、 following devices:a) bending device with two supports and a former as shown in Figure 1;b) bending device with a V-block and a former as shown in Figure 2;c) bending device with a clamp as shown in Figure 3.Figure 1 Bending device with two supports and a formerFigure 2 Bending device with a V-block
41、 and a formerDIN EN ISO 7438:2016-07 EN ISO 7438:2016 (E)6 Key1 clamp2 formerFigure 3 Bending device with a clamp4.2 Bending device with supports and a former4.2.1 The length of the supports and the width of the former shall be greater than the width or diameter of the test piece. The diameter of th
42、e former is determined by the product standard. The test piece supports and the former shall be of sufficient hardness (see Figure 1).4.2.2 Unless otherwise specified, the distance between the supports, l, shall be:la=+ ()Da32(1)and shall not change during the bend test.NOTE When the distance betwee
43、n the supports (l) is specified smaller than or equal to D + 2a, it can result in clamping during the test and stretch forming of the test piece.4.3 Bending device with a V-blockThe tapered surfaces of the V-block shall form an angle of 180 (see Figure 2). The angle is specified in the relevant stan
44、dard.DIN EN ISO 7438:2016-07 EN ISO 7438:2016 (E)7 The edges of the V-block shall have a radius between 1 to 10 times the thickness of the test piece and shall be of sufficient hardness.4.4 Bending device with a clampThe device consists of a clamp and a former of sufficient hardness; it may be equip
45、ped with a lever for applying force to the test piece (see Figure 3).Because the position of the left face of the clamp could influence the test results, the left face of the clamp (as shown in Figure 3) should not reach up to or beyond the vertical line through the centre of the circular former sha
46、pe.5 Test piece5.1 GeneralRound, square, rectangular, or polygonal cross-section test pieces shall be used in the test. Any areas of the material affected by shearing or flame cutting and similar operations during sampling of test pieces shall be removed. However, testing a test piece, the affected
47、parts of which have not been removed, is acceptable, provided the result is satisfactory.5.2 Edges of rectangular test piecesThe edges of rectangular test pieces shall be rounded to a radius not exceeding the following values: 3 mm, when the thickness of the test pieces is 50 mm or greater; 1,5 mm,
48、when the thickness of the test pieces is less than 50 mm and more than or equal to 10 mm (inclusive); 1 mm when the thickness is less than 10 mm.The rounding shall be made so that no transverse burrs, scratches or marks are formed which might adversely affect the test results. However, testing a test piece, the edges of which have not been
