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1、 Reference number ISO 34-2:2007(E) ISO 2007 INTERNATIONAL STANDARD ISO 34-2 Second edition 2007-07-15 Rubber, vulcanized or thermoplastic Determination of tear strength Part 2: Small (Delft) test pieces Caoutchouc vulcanis ou thermoplastique Dtermination de la rsistance au dchirement Partie 2: Petit
2、es prouvettes (prouvettes de Delft) Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 08/07/2007 01:24:41 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 3
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6、elow. COPYRIGHT PROTECTED DOCUMENT ISO 2007 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the add
7、ress below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2007 All rights reserved Copyright International Organization fo
8、r Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 08/07/2007 01:24:41 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 34-2:2007(E) ISO 2007 All rights reserved iii Contents Page Foreword iv 1 Sc
9、ope . 1 2 Normative references. 1 3 Principle. 1 4 Apparatus 2 5 Test pieces 2 5.1 Shape and dimensions. 2 5.2 Measurement of dimensions . 2 5.3 Time interval between vulcanization and testing 6 5.4 Number 6 6 Temperature of test 6 7 Procedure 6 8 Expression of results . 6 9 Precision 7 10 Test repo
10、rt . 7 Annex A (informative) Precision. 8 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 08/07/2007 01:24:41 MDTNo reproduction or networking permitted without license from IHS -,-,-
11、 ISO 34-2:2007(E) iv ISO 2007 All rights reserved Foreword ISO (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
12、 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 closely with the Internationa
13、l Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards 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
14、 adopted by the technical committees are circulated to the member bodies for voting. Publication as an International 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
15、 patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 34-2 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee SC 2, Testing and analysis. This second edition cancels and replaces the first edition (ISO 34-2:1996), wh
16、ich has been revised principally to update the normative references (ISO 471, ISO 3383 and ISO 4648 have been replaced by ISO 23529). Since ISO 5893 has also been revised, the force-measuring accuracy of the tensile-testing machine has been corrected to class 2. The text concerning precision in Clau
17、se 9 has been combined with Annexes A, B and C to give a new Annex A. In addition, the layout of Clause 10, the test report, has been updated. ISO 34 consists of the following parts, under the general title Rubber, vulcanized or thermoplastic Determination of tear strength: Part 1: Trouser, angle an
18、d crescent test pieces Part 2: Small (Delft) test pieces Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 08/07/2007 01:24:41 MDTNo reproduction or networking permitted without license
19、 from IHS -,-,- INTERNATIONAL STANDARD ISO 34-2:2007(E) ISO 2007 All rights reserved 1 Rubber, vulcanized or thermoplastic Determination of tear strength Part 2: Small (Delft) test pieces WARNING Persons using this part of ISO 34 should be familiar with normal laboratory practice. This part of ISO 3
20、4 does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions. CAUTION Certain procedures specified in this part of
21、ISO 34 may involve the use or generation of substances, or the generation of waste, that could constitute a local environmental hazard. Reference should be made to appropriate documentation on safe handling and disposal after use. 1 Scope This part of ISO 34 specifies a method for the determination
22、of the tear strength of small test pieces (Delft test pieces) of vulcanized or thermoplastic rubber. NOTE The method does not necessarily give results agreeing with those given by the method described in ISO 34-1, which uses trouser, angle and crescent test pieces. It is used in preference to ISO 34
23、-1 when the available material is limited, and may be particularly suitable for testing small finished products. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated referen
24、ces, the latest edition of the referenced document (including any amendments) applies. ISO 5893:2002, Rubber and plastics test equipment Tensile, flexural and compression types (constant rate of traverse) Specification lSO/TR 9272, Rubber and rubber products Determination of precision for test metho
25、d standards ISO 23529:2004, Rubber General procedures for preparing and conditioning test pieces for physical test methods 3 Principle The force required to tear across the width of a small test piece containing a slit in the centre is measured. Copyright International Organization for Standardizati
26、on Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 08/07/2007 01:24:41 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 34-2:2007(E) 2 ISO 2007 All rights reserved 4 Apparatus 4.1 Tensile-testing machine, comply
27、ing with the requirements of ISO 5893, capable of measuring force with an accuracy corresponding to class 2 as defined in ISO 5893:2002, and with a rate of traverse of the moving grip of 500 mm/min 50 mm/min. The capacity of the test machine shall be such that the force required to tear the test pie
28、ce will be not less than 15 % or more than 85 % of that capacity. 4.2 Die, for cutting out the test piece. The construction of the die and the knife which cuts the slit are shown in Figures 1 and 2. 4.3 Micrometer gauge, complying with the requirements of ISO 23529 and having a circular foot approxi
29、mately 6 mm in diameter which exerts a pressure of 22 kPa 5 kPa. 4.4 Travelling microscope, giving at least 10 magnification, fitted with a graticule graduated at 0,01 mm intervals. 5 Test pieces 5.1 Shape and dimensions The test pieces shall be rectangular and shall conform to the dimensions shown
30、in Figure 3 and Table 1. The test pieces shall be cut from a sheet by punching with the die (4.2), using a single blow of a mallet or (preferably) a single stroke of a press. The rubber can be wetted with water or a soap solution, and shall be supported on a sheet of slightly yielding material (for
31、example leather, rubber belting or cardboard) on a flat, rigid surface. The tear strength is particularly susceptible to grain effects in the rubber. Normally, all test pieces are prepared with the grain at right angles to their length, but, in cases where grain effects are significant and are to be
32、 evaluated, two sets of test pieces shall be cut from the sheet, one at right angles to the grain and the other parallel to the grain. The thickness d of the test pieces shall be 2,0 mm 0,2 mm. 5.2 Measurement of dimensions 5.2.1 Measurement of thickness Measure the thickness of the test piece by me
33、thod A of ISO 23529:2004. Take at least three gauge readings in the region of the slit. If an even number of readings is taken, use the average of the two median values as the result. If an odd number of readings is taken, use the median value. No reading shall deviate by more than 2 % from the valu
34、e used. When the test results are to be used for comparative purposes, the thickness of any test piece shall not vary by more than 10 % from the mean thickness of all the test pieces. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employe
35、es/1111111001, User=Wing, Bernie Not for Resale, 08/07/2007 01:24:41 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 34-2:2007(E) ISO 2007 All rights reserved 3 Dimensions in millimetres b3 = W w (second method) Figure 1 Die for Delft test pieces Copyright International
36、 Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 08/07/2007 01:24:41 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 34-2:2007(E) 4 ISO 2007 All rights reserved Dimensions in mi
37、llimetres a) Enlarged detail of blade for cutting out test piece b) Enlarged detail of small blade for cutting slit a Cutting edge. Figure 2 Details of Delft test piece die cutting edges a Slit to be symmetrical with the width. Figure 3 Test piece Table 1 Dimensions of test piece Dimension Value mm
38、L Length 60 B Width 9,0 0,1 b Slit length 5,0 0,1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 08/07/2007 01:24:41 MDTNo reproduction or networking permitted without license from I
39、HS -,-,- ISO 34-2:2007(E) ISO 2007 All rights reserved 5 5.2.2 Measurement of the total width outside the slit 5.2.2.1 General The total width outside the slit b3 corresponds to the rubber to be torn. Two methods of measurement can be used. The first method is theoretically more exact, but is diffic
40、ult to use in practice. The second method, which is in common use, is simpler but can give different results. Unless otherwise specified, use the second method. Results obtained using test pieces measured by different methods shall not be compared. 5.2.2.2 First method: Measurement by travelling mic
41、roscope Variations occur in the length of the slit and in the total width of the test piece when the same die is used to prepare test pieces from rubber of different hardnesses. Moreover, the slit might not be uniform throughout its depth, but might be wider at one surface. Take one test piece which
42、 has been cut out with the die, therefore, and use it to measure the width to be torn by cutting the test piece through with a sharp razor blade in the plane of the slit and measuring the cut surfaces (width on either side of the slit) with a travelling microscope. The ends of the slit are curved as
43、 shown in Figure 4, and an attempt shall be made to allow for this curvature when measuring the width on either side of the slit, as follows. Take as the width on the left-hand side b1, which is the distance from the line AB to an imaginary line AB which is situated so that the total area S1 + S2 =
44、S3. Similarly, on the right-hand side, imagine a line CD situated so that the total area S1 + S2 = S3 and b2 is the width. The total width b3 outside the slit (i.e. the rubber to be torn) is then b1 + b2. Dimensions in millimetres b3 = b1 + b2 (first method) a Top. b Bottom. Figure 4 Section through
45、 slit in Delft test piece Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 08/07/2007 01:24:41 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 34-2:2007(E
46、) 6 ISO 2007 All rights reserved 5.2.2.3 Second (simpler) method: Measurement from the dimensions of the die used to cut the test piece Calculate b3 from the dimensions of the die (see Figure 1), using the following equation: 3 bWw= where W is the measured distance between the cutting edges of the d
47、ie; w is the measured width of the blade for cutting the slit. 5.3 Time interval between vulcanization and testing The time between vulcanization and testing shall be in accordance with ISO 23529. 5.4 Number At least three and preferably six test pieces shall be tested. 6 Temperature of test The tes
48、t is normally carried out at a standard laboratory temperature of 23 C 2 C or 27 C 2 C, as specified in ISO 23529. If the test is to be carried out at a temperature other than a standard laboratory temperature, condition the test piece, immediately prior to testing, for a period sufficient for it to reach substantial temperature equilibrium at the test temperature. Keep this p