BS EN 12384-1999 Copper and copper alloys - Determination of spring bending limit on strip《铜和铜合金 带材弹性弯曲极限值测定》.pdf

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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 12384:1999 Incorpor

2、ating Corrigendum No. 1 The European Standard EN 12384:1999 has the status of a British Standard ICS 77.150.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Copper and copper alloys Determination of spring bending limit on stripThis British Standard, having been prepared und

3、er the direction of the Engineering Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 July 1999 BSI 07-2000 ISBN 0 580 32069 3 BS EN 12384:1999 Amendments issued since publication Amd. No. Date Comments 10970 Corrigendum No. 1 July 2000 Amends

4、 equation (1). National foreword This British Standard is the English language version of EN 12384:1999. The UK participation in its preparation was entrusted by Technical Committee NFE/34, Copper and copper alloys, to Subcommittee NFE/34/1, Wrought and unwrought copper and copper alloys, which has

5、the responsibility to: aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list o

6、f 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 Standards Catalogue under the section entitled “Internation

7、al Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a Britis

8、h 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 title page, pages 2 to 9 and a back cover. The BSI coyright notice displayed in this document indicates when the document was last issued.CEN Eu

9、ropean Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1999 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12384:1999 E EU

10、ROPEAN STANDARD EN 12384 NORME EUROPE ENNE EUROPA ISCHE NORM January 1999 ICS 77.150.30 Descriptors: copper, copper alloys, flexural tests, determination, modulus of elasticity, elastic limit English version Copper and copper alloys Determination of spring bending limit on strip Cuivre et alliages d

11、e cuivre De termination de la limite e lastique en flexion de bande Kupfer und Kupferlegierungen Bestimmung der Federbiegegrenze von Ba ndern This European Standard was approved by CEN on 13 December 1998. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the

12、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 obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in t

13、hree 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 Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of

14、Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN 12384:1999 BSI 07-2000 Foreword This European Standard has been prepared by Technical Committee CEN

15、/TC 133, Copper and copper alloys, the Secretariat of which is held by DIN. 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 1999, and conflicting national standards shall be withdrawn at the

16、latest by July 1999. Within its programme of work, Technical Committee CEN/TC 133 requested CEN/TC 133/WG 2, Rolled flat products, to prepare the following standard: EN 12384, Copper and copper alloys Determination of spring bending limit on strip. According to the CEN/CENELEC Internal Regulations,

17、the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Ki

18、ngdom. Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Definitions 3 4 General principle 3 5 Details of the test 3 6 Apparatus 3 6.1 General 3 6.2 Supports 4 6.3 Loading nose 4 6.4 Loading weight 4 6.5 Permanent deflection 4 7 Test pieces 4 7.1 General 4 7.2 Number 4 7.3 Marking 4 7.4

19、Determination of the thickness 5 8 Procedure 5 8.1 General 5 8.2 Determination of the modulus of elasticity 5 8.3 Determination of spring bending limit 5 9 Precision 6 10 Test report 6 Annex A (normative) Determination of spring bending limit 7 Annex B (informative) Bibliography 9Page 3 EN 12384:199

20、9 BSI 07-2000 1 Scope This European Standard specifies test methods to determine the modulus of elasticity E and the spring bending limit s FB of strip in thicknesses from 0,05 mm up to and including 1,0 mm. This standard applies to strip specified in EN 1654. 2 Normative references This European St

21、andard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply

22、 to this European Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. EN 1654, Copper and copper alloys Strip for springs and connectors. NOTE Informative references to documents used in the preparation of

23、 this standard and cited at the appropriate places in the text, are listed in a bibliography, see annex B. 3 Definitions For the purposes of this standard, the following definitions apply. 3.1 modulus of elasticity E relationship between stress and strain in the elastic range In accordance with this

24、 European Standard it is calculated on the basis of the linear beam flexure theory, from the equation: E = (1) 3 3 F 43 w3 s l t where: E is the modulus of elasticity (Youngs modulus), in newtons per square millimetre; F is the force, in newtons; l is the distance between the supports, in millimetre

25、s; s is the deflection, in millimetres; t is the thickness of the strip, in millimetres; w is the width of the test piece, in millimetres. 3.2 spring bending limit s FB stress value up to which the material may be subjected to flexural stress without a given small plastic deformation being exceeded.

26、 It is defined as the outer fibre stress in a test piece of thickness t which, when resting on supports with a distance between them of: l = 100 (2) k3 t where: k is a constant, 0,8 mm; l is the distance between the supports, in millimetres; t is the thickness of the strip, in millimetres; and relie

27、ved of load, shows a permanent deflection s bl of 50mm. It is calculated on the basis of equation (3): s FB = (3) 63 E3 t3 s* l 2 1+1 7( s*/l) 2,4 where: s FB is the spring bending limit, in newtons per square millimetre; E is the modulus of elasticity as defined in 3.1; s* is the forced deflection

28、which, given the distance between supports specified in this standard on the basis of equation (2), results in a permanent deflection of 50mm. NOTE Equation (3) is an approximation. In accordance with W. Kutschera 1, at the extreme low end of the thickness range within the scope of this standard, th

29、e deviation from the real value of spring bending limit would be 1,2 % max. 4 General principle The test takes the form of a bend test with the test piece supported on two supports near the ends of the test piece, and a load applied midway between the supports. Elastic deflection is measured to dete

30、rmine the modulus of elasticity and permanent deflection is measured to determine the spring bending limit. 5 Details of the test For technical and metrological reasons, the given range of thicknesses is divided for test purposes into range A (see Table 1) for strip with thicknesses from 0,15 mm up

31、to and including 1,0 mm, and range B (see Table 1) for strip with thicknesses from 0,05 mm up to and including 0,20 mm. Where the two ranges overlap, i.e. for thicknesses from 0,15 mm up to and including 0,20 mm, the results of testing are the same. Unless explicitly referring to them separately, th

32、e requirements of clauses 6 to 9 apply to both ranges. 6 Apparatus 6.1 General The test set-up (see Figure 1) shall consist of two supports, which are able to slide, and a deflectometer, which comprises a weight for applying load and a deflection device. The deflectometer shall act on the test piece

33、 at its centre between the supports. NOTE Equation (3) is applicable to deflections up to s* = 0,463 l.Page 4 EN 12384:1999 BSI 07-2000 1 loading nose 2 test piece 3 support with straight, horizontal edge 4 support with curved edge Figure 1 Test set-up (schematic) 6.2 Supports The supports shall be

34、two steel blocks, 10,2 mm wide and of right-angled triangular section. Sharp supporting edges shall be formed by a 608 angle of the triangular section, with edge radius less than 0,03 mm. One of the supporting edges shall be straight and the other one convex with a radius of curvature of 15 mm perpe

35、ndicular to the right angle triangular section. The distance between the supports shall be continuously adjustable, symmetrically to the axis of loading, to within 0,1 mm in a range from 15 mm up to and including 100 mm. 6.3 Loading nose The loading nose used for applying the load and producing the

36、deflection shall be in contact with the test piece at two points (see Figure 2). The two points at which the load is applied shall lie to the left and right of the longitudinal axis of the test piece. The centre of the test piece shall be left free to permit measurement of the deflection. 1 test pie

37、ce 2 loading nose Figure 2 Loading nose (schematic) 6.4 Loading weight The loading weight required for determining the modulus of elasticity shall have a mass of 100,0 g 1,0 g for range A (see Table 1) test pieces and 10,0 g 0,10 g for range B (see Table 1) test pieces. 6.5 Permanent deflection The

38、permanent deflection required for calculating the spring bending limit shall be produced by progressive forced deflection and relief. Increments of 0,667 mm have been found to be expedient. 7 Test pieces 7.1 General Test pieces corresponding to the dimensions given in Table 1 shall be cut from sampl

39、es of strip. Test pieces shall be taken from the sample in such a way that the characteristics of the material are not affected. Scissors shall not be used. The test pieces shall be cut or milled from the sample with the aid of a cutting tool, the edges being as free from burrs as possible and the d

40、irection of cut being parallel to that of rolling unless another alignment is requested by the purchaser. Table 1 Dimensions of test pieces Dimensions in millimetres Range Thickness Width Length A 1,0 to 0,30 10 150 0,30 to 0,15 70 B 0,20 to 0,10 60 0,10 to 0,05 50 The longitudinal edges shall be de

41、burred, care being taken to avoid deforming the test pieces or damaging their surfaces. On no account shall test pieces be straightened or bent, as this alters their spring characteristics. 7.2 Number A total of four test pieces is required for determining the modulus of elasticity and the spring be

42、nding limit. Two test pieces per surface side shall be measured from each sample. 7.3 Marking The sides of the test pieces shall be unambiguously marked as top or bottom of the strip. Normally the convex side of strips curved lengthwise is indicated as the top and the concave side as the bottom.Page

43、 5 EN 12384:1999 BSI 07-2000 7.4 Determination of the thickness Since the thickness of the test piece enters the calculation of the modulus of elasticity, raised to the third power, it shall be measured with great care. The thickness of each test piece shall be determined in the middle, to the neare

44、st 1mm. 8 Procedure 8.1 General The elastic deflection, when the modulus of elasticity is being measured, and the permanent deflection, in the case of spring bending limit measurements, shall be measured midway between the supports. The deflection shall be measured when the test piece is relieved of

45、 load. The limits of error shall not exceed a maximum of 2mm. The modulus of elasticity may be determined more than once for the same test piece. Test pieces which have already been tested in order to determine the modulus of elasticity may be used to determine the spring bending limit, but this may

46、 be determined only once per test piece as the elastic and plastic characteristics of the test pieces are changed as a result of the test. The test shall be carried out at a temperature between 188C and 288C. 8.2 Determination of the modulus of elasticity To determine the modulus of elasticity, the

47、distance between the supports shall be: for range A test pieces: 1003 t; for range B test pieces: 215,43 t. The modulus of elasticity of test pieces less than 0,07 mm thick shall not be determined, as the uncertainty of measurement increases inversely to the span between the supports. In such cases,

48、 the spring bending limit may be calculated using the guideline value specified for the modulus of elasticity. The following applies to test pieces of both ranges. The test piece shall be placed symmetrically on the supports, this position being taken to be the zero position for the deflection measu

49、rement. The deflection s produced by the loading weight shall be measured and the result used to calculate the modulus of elasticity in accordance with equation (1). The modulus of elasticity of four test pieces per sample shall be determined, two being tested top side up, and two bottom side up. For calculating the spring bending limit, either the mean or the respective single value of the modulus of elasticity may be used. 8.3 Determination of spring bending limit 8.3.1 General The spring bending limit shall be determ