BS EN 12814-1-2000 Testing of welded joints of thermoplastics semi-finished products - Bend test《热塑性半成品焊接接头试验 弯曲试验》.pdf

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1、BRITISH STANDARD BS EN 12814-1:2000 Incorporating Corrigendum No. 1 Testing of welded joints of thermoplastics semi-finished products Part 1: Bend tests The European Standard EN 12814-1:1999 has the status of a British Standard ICS 25.160.40 BS EN 12814-1:2000 This British Standard, having been prep

2、ared under the direction of the Sector Committee Materials and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 January 2000 BSI 28 November 2003 ISBN 0 580 35896 8 National foreword This British Standard is the official English language version of

3、EN 12814-1:1999, including Corrigendum September 2003. The UK participation in its preparation was entrusted to Technical Committee PRI/80, Welding thermoplastics, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cros

4、s-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 entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of

5、British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; pr

6、esent to the responsible international/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. Summary of pages This document comprises a front cover, a

7、n inside front cover, the EN title page, pages 2 to 15 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments 14807 Corrigendum No. 1 28 November 2003 Addition to clause 6 and chang

8、es made to Table 3. EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12814-1 November 1999 ICS 25.160.40 Incorporating Corrigendum September 2003 English version Testing of welded joints of thermoplastics semi-finished products - Part 1: Blend test Essai des assemblages souds sur produits semi-f

9、inis thermoplastiques - Partie 1: Essais de pliage Prfen von Schweiverbindungen aus thermoplastischen Kunststoffen - Teil 1: Biegeversuch This European Standard was approved by CEN on 30 September 1999. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the con

10、ditions 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 thre

11、e 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 Aus

12、tria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Central Se

13、cretariat: 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 12814-1:1999 EPage 2 EN 12814-1:1999 Contents Page Foreword 3 1 Scope. 3 2 Normative references . 3 3 Terms and definitions. 4 3.1

14、face bend. 4 3.2 root bend . 4 3.3 side bend . 4 3.4 initial angle “ i “. 4 3.5 final angle “ f “ 4 3.6 bend angle “ “ . 4 4 Symbols and designations. 4 5 Principle of the test 5 6 Sampling procedures . 8 7 Dimensions of test specimens and test arrangement . 9 8 Cutting of test specimens 9 8.1 Gener

15、al requirement 9 8.2 Cutting of tubes. 10 9 Mechanical testing. 11 10 Testing machine. 11 11 Practical determination of bend angle . 12 11.1 Method 1. 12 11.2 Method 2. 12 12 Test report 13 Annex A (informative) Manual test . 15 Page 3 EN 12814-1:1999 Foreword This European Standard has been prepare

16、d by Technical Committee CEN/TC 249, Plastics, the Secretariat of which is held by IBN. 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 May 2000, and conflicting national standards shall be withdr

17、awn at the latest by May 2000. According to the CEN/CENELEC Internal Regulations, 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, Luxem

18、bourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. 1 Scope This standard specifies the dimensions and the method for sampling and preparing test specimens, together with the conditions for carrying out the bend test. The result of the test is also influenced by

19、the deformation behaviour of the tested material, the kind of welding process and the geometry of the sample. The test is applicable to plate and tube butt jointed assemblies made from thermoplastic materials filled or unfilled, but not reinforced, irrespective of the welding process used. It is not

20、 applicable to assemblies with a wall thickness 3 mm. 2 Normative references This European Standard 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. Fo

21、r dated references, subsequent amendments to or revisions of any of these publications apply 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. ISO 2768-1 General tolerances - Part 1: Tole

22、rances for linear and angular dimensions without individual tolerance indications ISO 2818 Plastics - Preparation of test specimens by machining ISO 5893 Rubber and plastics test equipment - Tensile, flexural and compression types (constant rate of traverse) - Description Page 4 EN 12814-1:1999 3 Te

23、rms and definitions For the purposes of this European Standard, the following definitions apply: 3.1 face bend the face corresponding to the open side of the groove is subjected to extension. 3.2 root bend the face corresponding to the root of the weld is subjected to extension. 3.3 side bend one of

24、 the faces of the test specimen corresponding to the cross section of the weld is subjected to extension. 3.4 initial angle “ I ” angle between the two sides of the test specimen above the rollers before the test. 3.5 final angle “ f ” angle between the two sides of the test specimen above the rolle

25、rs when the test is terminated. 3.6 bend angle “ ” angle calculated from the difference between the initial angle and final angle. 4 Symbols and designations Symbols and designations are given in Table 1. Page 5 EN 12814-1:1999 Table 1 - Symbols and designations Symbols Designation Units a Thickness

26、 of test piece millimetre b Width of test specimen millimetre d Diameter of ram end millimetre D Diameter of rollers millimetre D aDistance between axes of rollers millimetre D nNominal outside diameter of tube millimetre H Ram displacement millimetre Ho Initial ram position millimetre H fFinal ram

27、position millimetre L Length of test specimen millimetre iInitial angle Degree fFinal angle Degree Bend angle Degree 5 Principle of the test A bend test may be used in conjunction with other tests (e.g. tensile, tensile creep, macrographic, .), to assess the performance of butt jointed assemblies, m

28、ade from thermoplastics materials1 ) . The test consists of subjecting a test specimen to deformation by bending at a constant speed without reversing the direction of bending during the test. The bend angle (ram displacement) and fracture appearance provide a guide to the ductility of a welded join

29、t and hence the weld quality 2) . The final angle, f , (final ram position) is taken when either fracture occurs, a crack is visible with the naked eye or a maximum load is reached 3) . If no crack occurs the test is terminated at either a bend angle of 160 or at a ram displacement given in Table 2.

30、 1 ) The test may also be used to optimize welding conditions. In this case it is acceptable to use non standard test conditions: for example to decrease the test temperature or increase the speed of bending. 2)Simple manual test is described in annex A (informative). 3)The maximum load may not corr

31、elate with the failing of the welded sample. Page 6 EN 12814-1:1999 Table 2 - Ram displacements corresponding to the bend angle of 160 Dimensions in millimetres Thickness of test specimens Ram displacement 3 a 5 60 5 a 15 70 15 a 20 85 20 a 25 170 25 a 30 150 The bend angle and the ram displacement

32、are determined as described in Figures 1a and 1b. = i- fand H = H f- H oHo HfFigure 1a - Initial position Figure 1b - Final position Figure 1 - Determination of bend angle “ ” and ram displacement H The three different cases for the test are: - asymmetrical welds (see Figures 2 and 3); - symmetrical

33、 welds (see Figures 4 and 5); Page 7 EN 12814-1:1999 - side bend test (see Figure 6). For a thickness equal or above 30 mm the side bend test can be used, or the thickness of the test specimen can be reduced to less than 30 mm by machining from the side in contact with the ram end. Figure 2 - Face b

34、end test for asymmetrical welds Figure 3 - Root bend test for asymmetrical welds Figure 4 - Bend test for symmetrical welds Page 8 EN 12814-1:1999 1 Outside 2 Inside bead Figure 5 - Bend test on tubes 1 Thickness of the test piece Figure 6 - Side bend test 6 Sampling procedures The test specimens sh

35、all be cut perpendicular to the welded joint and machined at least eight hours after welding. Each test specimen is marked so that its original position in the test piece can be identified. No heat treatment or mechanical straightening operations are carried out on the test specimen. The bead shall

36、be removed from the side in contact with the ram end. The bead shall not be removed from the side subjected to extension. Page 9 EN 12814-1:1999 7 Dimensions of test specimens and test arrangement The values for the dimensions of the test specimens and the test arrangement are given in Table 3. All

37、dimensions are given with tolerances in accordance with ISO 2768-1 In the case of tubes, the internal diameter shall not be less than 15 mm. The preparation of plastics test specimens is described in ISO 2818. The joint is situated at the centre of the test specimen. The diameter of the rollers is 5

38、0 millimetres. For tubes, the width of the test specimen shall be equal to 0,1 D nwith a minimum value of 6 mm and a maximum value of 20 mm. Table 3 - Dimensions of test specimens and test arrangement Dimensions in millimetres Test type Test specimen Distance between rollers axes Diameter of ram end

39、 a b L D ad For plates Face 3 a 5 20 150 80 4 and 5 a 10 20 200 90 8 root 10 a 15 30 200 100 12,5 bend 15 a 20 30 250 120 16 20 a 30 30 380 160 25 Side bend 10 + 0,5 a 200 90 8 8 Cutting of test specimens 8.1 General requirement A maximum of 1 mm of the longitudinal edges of the test specimen to be

40、subjected to extension shall be removed at an angle of approximately 45. These chamfers shall be continuous through the bead according to Figure 7. Page 10 EN 12814-1:1999 1 Chamfer 2 Bead Figure 7 - Longitudinal chamfer of test specimens 8.2 Cutting of tubes The bend test specimens shall be cut eit

41、her radially or with parallel sides; as shown in Figures 8a and 8b. Figure 8a - Parallel cutting Figure 8b - Radial cutting Figure 8 - Cutting of test specimens Page 11 EN 12814-1:1999 9 Mechanical testing Test specimens shall be conditioned to a temperature of 23 C 2 C, and unless otherwise specifi

42、ed, the test shall be carried out at a room temperature of 23 C +2/-5 C. The ram speeds for some relevant thermoplastics materials are listed in Table 4. The ram speeds tolerances shall be in accordance with ISO 5893. Table 4 - Ram speed for some thermoplastics Material Speed mm/min PVC-U 10 PP-H, P

43、P-B, PVDF 20 PP-R, PE 50 NOTE For other materials the ram speed shall be chosen to ensure that the test is terminated in about one minute. At least five test specimens shall be tested for each welded test piece. In the case of asymmetrical welds, at least five test specimens shall be tested for each

44、 face of the weld. If up to two test specimens do not achieve the minimum bend angle as specified in the requirements, two further test specimens from the same welded test piece can be tested at the same face. No more than two additional test specimens shall be tested. 10 Testing machine The rate of

45、 travel of the ram shall be continuous, uniform and in accordance with clause 9. The rollers shall be free to rotate. Page 12 EN 12814-1:1999 11 Practical determination of bend angle Several methods are possible to determine the bend angle: 11.1 Method 1 The indicator fixed to the ram permits direct

46、 reading of the initial and final angles as described in Figure 9. Figure 9 - Determination of bend angle with indicator 11.2 Method 2 The bend angle can be measured with arms which remain in contact with the free ends of the test specimen throughout the test, as described in Figure 10. In order to

47、determine the correct angle at fracture, the value shall be recorded at the moment of fracture. Figure 10 - Determination of bend angle with arms Page 13 EN 12814-1:1999 12 Test report The test report shall refer to this standard and it shall include at least the following information: - complete id

48、entification of the test piece and test specimens; - temperature of the test specimen; - temperature of the test; - the ram speed; - the method used to determine the bend angle; - the value of the bend angle required, if applicable; - the appearance of the test specimen following the test: visual ex

49、amination of the ruptured surface; - the date of the test and the name and the signature of the operator; - initial angle for each test specimen; - final angle for each test specimen; - bend angle for each test specimen; - bending direction; - thickness of test specimen; - thickness of test piece (if different to test specimen); - width of test specimen; - diameter of ram end; - length of test specimen; - distance between axes of rolle