1、Metallic materials - Bend test The European Standard EN IS0 7438:2005 has the status of a British Standard ICs 77.040.10 BS EN IS0 7438:2005 British Standards NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Copyright European Committee for Standardization Provided by IHS under
2、 license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN IS0 7438:2005 National foreword This British Standard was published under the authority of the Standards Policy and Strategy Committee on 21 October 2005 This British Standard is the official En
3、glish language version of EN IS0 7438:2005. It is identical with IS0 7438:2005. It supersedes BS EN IS0 7438:2000 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee ISE/NFE/4, Mechanical testing of metals, to Subcommittee ISE/NFE/4/2, Ductility testing,
4、which has the responsibility to: - - aid enquirers to understand the text; present to the responsible internationaUEuropean committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate t
5、hem in the UK. - A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitl
6、ed ?International Standards Correspondence Index?, or by using the ?Search? facility of the BSI Electronic Catalogue or of British St andards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance
7、 with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN IS0 title page, the EN IS0 foreword page, the IS0 title page, pages ii to iv, pages 1 to 8, an inside back cover and a back cover.
8、 The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. IDate I Comments O BSI 21 October 2005 ISBN O 580 46375 3 Copyright European Committee for Standardization Provided by IHS under license with CENNot for Resa
9、leNo reproduction or networking permitted without license from IHS-,-,-EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM June 2005 ICs 77.040.1 O Supersedes EN IS0 7438:2000 English version Metallic materials - Bend test (IS0 7438:2005) Matriaux mtalliques - Essai de pliage (IS0 7438:2005) Metallisc
10、he Werkstoffe - Biegeversuch (IS0 7438:2005) This European Standard was approved by CEN on 13 June 2005. CEN members are bound to comply with the CENICENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration
11、. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat 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
12、 under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary
13、, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Noway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Sta
14、ssari, 36 B-1050 Brussels O 2005 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN IS0 7438:2005: E Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking pe
15、rmitted without license from IHS-,-,-EN IS0 7438:2005 Foreword This document (EN IS0 7438:2005) has been prepared by Technical Committee ISOTC 164 “Mechanical testing of metals“ in collaboration with Technical Committee ECISSTC 1 “Steel - Mechanical testing“, the secretariat of which is held by AFNO
16、R. 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 December 2005, and conflicting national standards shall be withdrawn at the latest by December 2005. This document supersedes EN IS0 7438:2000. A
17、ccording to the CENEEN ELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lit
18、huania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorse ment not ice The text of IS0 7438:2005 has been approved by CEN as EN IS0 7438:2005 without any modifications. Copyright European Committee for Standardization
19、 Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EN IS0 74382005 INTERNATIONAL STANDARD IS0 7430 Second edition 2005-06-1 5 Metallic materials - Bend test Matriaux mtalliques - Essai de pliage Reference number IS0 7438:2005(E)
20、Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ii Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or network
21、ing permitted without license from IHS-,-,-EN IS0 74382005 Contents Page Foreword iv 1 Scope . 1 2 Symbols and designations 1 3 Principle . 1 4 Test equipment . 2 5 Test piece 4 6 Procedure 5 7 Interpretation of results 7 8 Test report . 7 Annex A (informative) Determination of the bend angle from t
22、he measurement of the displacement of the former 8 iii Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EN IS0 7438:2005 Foreword IS0 (the International Organization for Standardi
23、zation) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to b
24、e represented on that committee. International organizations, governmental and non-governmental, in liaison with SO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standar
25、ds are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Intern
26、ational Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. IS0 shall not be held responsible for identifying any or all such patent rights. IS0 7438 was
27、 prepared by Technical Committee ISOTC 164, Mechanical testing of metals, Subcommittee SC 2, Ductility testing. This second edition cancels and replaces the first edition (IS0 7438: 1985), which has been technically revised. iv Copyright European Committee for Standardization Provided by IHS under l
28、icense with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EN IS0 74382005 Symbol a Metallic materials - Bend test Designation Unit mm Thickness or diameter of test piece (or diameter of the inscribed circle for pieces of polygonal cross-section) 1 Scope Distan
29、ce between the plane including the horizontal axis of supports and the central axis of the rounded portion of the former before test Distance between the vertical planes including the central axis and the vertical axis of each support and the vertical plane including the horizontal central axis of t
30、he former after test This International Standard specifies a method for determining the ability of metallic materials to undergo plastic deformation in bending. mm mm This International Standard applies to test pieces taken from metallic products, as specified in the relevant product standard. It is
31、 not applicable to certain materials or products, for example tubes in full section or welded joints, for which other standards exist. 2 Symbols and designations Symbols and designations used in the bend test are shown in Figures 1 and 2 and specified in Table 1. mm I b I Width of the test piece I m
32、m I L I Length of the test piece I mm I 1 I Distance between supports I mm I D I Diameter of the former I I a I Angle of bend I degrees r mm I I Internal radius of bend portion of test piece after bending I I f I Displacement of the former I mm C P 3 Principle The bend test consists of submitting a
33、test piece of round, square, rectangular or polygonal cross-section to 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
34、a 180“ bend, the two lateral surfaces may, depending on the requirements 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. 1 Copyright European Committee for Standardization Provided by IHS under license wi
35、th CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EN IS0 7438:2005 4 Test equipment 4.1 General The bend test shall be carried out in testing machines or presses equipped with the following devices: a) bending device with two supports and a former as shown in F
36、igure 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 D/ 2 /- v Figure 2 2 Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitte
37、d without license from IHS-,-,-EN IS0 74382005 Key 1 clamp 2 former Figure 3 4.2 Bending device with supports and a former 4.2.1 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 the former is determined by the produ
38、ct 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, I, shall be: a 1 =(D+3a)k- 2 and shall not change during the bend test. 4.3 Bending device with a V-block The tapered surfaces of t
39、he V-block shall form an angle of 180“- a (see Figure 2). The angle a is specified in the relevant standard. 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 clamp The device consists of
40、a clamp and a former of sufficient hardness; it may be equipped 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 th
41、e vertical line through the centre of the circular former shape. 3 Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EN IS0 7438:2005 5 Test piece 5.1 General Round, square, rectan
42、gular, 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 parts of which have not been removed, is accept
43、able, provided the result is satisfactory. 5.2 Edges of rectangular test pieces The 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, when the thickness of the test pieces is
44、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 b
45、een rounded, is acceptable, provided that the result is satisfactory. 5.3 Width of the test piece Unless otherwise specified in the relevant standard, the width of the test piece shall be as follows: a) the same as the product width, if the latter is equal to or less than 20 mm; b) when the width of
46、 a product is more than 20 mm: - (20 k 5) mm for products of thickness less than 3 mm, - between 20 mm and 50 mm for products of thickness equal to or greater than 3 mm. 5.4 Thickness of the test piece 5.4.1 The thickness of test pieces from sheets, strips and sections shall be equal to the thicknes
47、s of the product to be tested. If the thickness of the product is greater than 25 mm, it may be reduced by machining one surface to attain a thickness not less than 25 mm. During bending, the unmachined side shall be on the tension-side surface of the test piece. 5.4.2 Test pieces of round or polygo
48、nal cross-section shall have a cross-section equal to that of the product, if the diameter (for a round cross-section) or inscribed circle diameter (for a polygonal cross-section) does not exceed 30 mm. When the diameter, or the inscribed circle diameter, of the test piece exceeds 30 mm up to and including 50 mm, it may be reduced to not less than 25 mm. When the diameter, or inscribed circle diameter, exceeds 50 mm it shall be reduced to not less than 25 mm (see Figure 4). During bending, the unmachined side shall be on the tension-side surface of the test piec
