1、BSI Standards Publication BS ISO 815-2:2014 Rubber, vulcanized or thermoplastic Determination of compression set Part 2: At low temperaturesBS ISO 815-2:2014 BRITISH STANDARD National foreword This British Standard is the UK implementation of ISO 815-2:2014. It supersedes BS ISO 815-2:2008 which is
2、withdrawn. The UK participation in its preparation was entrusted to Technical Committee PRI/22, Physical testing of rubber. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of
3、a contract. Users are responsible for its correct application. The British Standards Institution 2014. Published by BSI Standards Limited 2014 ISBN 978 0 580 78735 5 ICS 83.060 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under
4、 the authority of the Standards Policy and Strategy Committee on 30 November 2014. Amendments issued since publication Date Text affectedBS ISO 815-2:2014 ISO 2014 Rubber, vulcanized or thermoplastic Determination of compression set Part 2: At low temperatures Caoutchouc vulcanis ou thermoplastique
5、Dtermination de la dformation rmanente aprs compression Partie 2: basses tempratures INTERNATIONAL STANDARD ISO 815-2 Second edition 2014-11-01 Reference number ISO 815-2:2014(E)BS ISO 815-2:2014ISO 815-2:2014(E)ii ISO 2014 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2014 All rights reserve
6、d. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO a
7、t the address 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 SwitzerlandBS ISO 815-2:2014ISO 815-2:2014(E)Contents Page Foreword iv Int
8、roduction v 1 Scope . 1 2 Normative references 1 3 Principle 1 3.1 Method 1. 1 3.2 Method 2. 2 4 Apparatus for low temperature tests 2 4.1 Method 1. 2 4.2 Method 2. 4 5 Calibration 6 6 Test pieces . 6 6.1 Dimensions . 6 6.2 Preparation 7 6.3 Number 7 6.4 Time interval between production and testing
9、7 6.5 Conditioning 7 7 Test conditions . 8 7.1 Duration of test . 8 7.2 Temperature of test . 8 8 Procedure. 8 8.1 Method 1. 8 8.2 Method 2. 9 9 Expression of results .10 10 Precision 10 11 Test report 10 Annex A (normative) Calibration schedule 12 Bibliography .16 ISO 2014 All rights reserved iiiBS
10、 ISO 815-2:2014ISO 815-2:2014(E) 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 member body inte
11、rested 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 International Electrotechnica
12、l Commission (IEC) on all matters of electrotechnical 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 docu
13、ments should be noted. This document was drafted 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 responsi
14、ble for identifying any or all such patent 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 fo
15、r the convenience of users and does not constitute 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 UR
16、L: Foreword - Supplementary information The committee responsible for this document is ISO/TC45, Rubber and rubber products, SC 2, Testing and analysis. This second edition cancels and replaces the first edition (ISO 815-2:2008), which has been technically revised, mainly by addition of method 1 and
17、 a calibration schedule (Annex A). ISO 815 consists of the following parts, under the general title Rubber, vulcanized or thermoplastic Determination of compression set: Part 1: At ambient or elevated temperatures Part 2: At low temperaturesiv ISO 2014 All rights reservedBS ISO 815-2:2014ISO 815-2:2
18、014(E) Introduction Allowing measurement and recording of the compression set at low temperature is very sensitive to testing conditions, and the values obtained can differ a lot especially for type B test pieces. That is why two measurement methods have been introduced. Method 2 generally gives a h
19、igher compression set than method 1, and this difference should be taken into account when preparing material specifications. Those methods are intended to measure the ability of rubbers of hardness within the range 10 IRHD to 95 IRHD to retain their elastic properties at specified temperatures afte
20、r prolonged compression at constant strain (normally 25 %) under one of the alternative sets of conditions described. For rubber of nominal hardness 80 IRHD and above, a lower compression strain is used: 15 % for a nominal hardness from 80 IRHD to 89 IRHD, and 10 % for a nominal hardness from 90 IRH
21、D to 95 IRHD. ISO 2014 All rights reserved vBS ISO 815-2:2014ISO 815-2:2014(E)vi ISO 2014 All rights reservedBS ISO 815-2:2014Rubber, vulcanized or thermoplastic Determination of compression set Part 2: At low temperatures WARNING 1 Persons using this part of ISO 815 should be familiar with normal l
22、aboratory practice. This part of ISO 815 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. WARNING 2 Cert
23、ain procedures specified in this part of ISO 815 can involve the use of 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 81
24、5 specifies two methods for the determination of the compression set characteristics of vulcanized and thermoplastic rubbers at low temperatures. Method 1 derives from the methodology used in ISO 815-1. Method 2 uses a specified testing device, allowing to measure and record the test piece thickness
25、 during recovery. Due to the load applied during recovery in method 2, no correlation can be established between the results given by both methods. NOTE When rubber is held under compression, physical or chemical changes can occur that prevent the rubber returning to its original dimensions after re
26、lease of the deforming force. The result is a set, where the magnitude of which depends on the time and temperature of compression as well as on the time, temperature, and conditions of recovery. At low temperatures, changes resulting from the effects of glass hardening or crystallization become pre
27、dominant and, since these effects are reversed by raising the temperature, it is necessary for all measurements to be undertaken at the test temperature. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its app
28、lication. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 18899:2013, Rubber Guide to the calibration of test equipment ISO 23529:2010, Rubber General procedures for preparing and cond
29、itioning test pieces for physical test methods 3 Principle 3.1 Method 1 A test piece of known thickness is compressed at standard laboratory temperature to a defined strain, which is then maintained constant for a specified time at a fixed low temperature. The compression is totally released and, af
30、ter the test piece has been allowed to freely recover at the same fixed low temperature, the thickness of the test piece is again measured. INTERNATIONAL ST ANDARD ISO 815-2:2014(E) ISO 2014 All rights reserved 1BS ISO 815-2:2014ISO 815-2:2014(E) 3.2 Method 2 A test piece of known thickness is compr
31、essed at standard laboratory temperature to a defined strain, which is then maintained constant for a specified time at a fixed low temperature. The compression is released and the test piece is allowed to recover at this temperature under a given pressure according to ISO 23529:2010 for thickness m
32、easurement. The thickness is measured either at intervals after the release of the strain (so that an assessment of compression set characteristics can be obtained by plotting of recovery against time at the low temperature) or a specified time after the release of the strain. 4 Apparatus for low te
33、mperature tests 4.1 Method 1 4.1.1 Compression assembly, consisting of compression plates, steel spacers, and clamping device. A typical assembly is shown in Figure 1. A quick release mechanism as shown on Figure 2 may also be used. 4.1.1.1 Compression plates, comprising a pair of parallel, flat, hi
34、ghly polished chromium-plated steel or highly polished stainless-steel plates, between the faces of which the test piece is compressed. The plates shall be sufficiently rigid to ensure that, with a test piece under load, no compression plate bends by more than 0,01 mm, and of sufficient size to ensu
35、re that the whole of the test piece, when compressed between the plates, remains within the area of the plates. NOTE A surface finish not worse than Ra 0,4 m (see ISO 4287) has been found to be suitable. Such an Ra can be obtained by a grinding or polishing operation. 4.1.1.2 Steel spacer(s), to pro
36、vide the required compression, if necessary. Whether spacer(s) will need to be used or not will depend on the design of the compression apparatus. If used, the spacer(s) shall be of such size and shape that contact with the compressed test piece is avoided. The height of the spacer(s) shall be chose
37、n so that the compression applied to the test piece is (25 2) % for hardnesses below 80 IRHD, (15 2) % for hardnesses between 80 IRHD and 89 IRHD, (10 1) % for hardnesses of 90 IRHD and higher. 4.1.1.3 Clamping device, a simple screw device (Figure 1) or a clamping device as shown on Figure 2 are ad
38、equate. 4.1.2 Low-temperature cabinet, capable of maintaining the compression apparatus and test pieces at the test temperature within the tolerance limits specified in 7.2. The low-temperature cabinet can be mechanically refrigerated or it can be cooled directly by dry ice or liquid nitrogen. The c
39、abinet shall be designed so that it is possible to release the test pieces and carry out the subsequent thickness measurements without direct contact, e.g. by means of hand-holes fitted with gloves or a remote-handling device. The cabinet shall be capable of maintaining the temperature within specif
40、ied limits while these operations are being carried out. The time to reach a steady-state temperature depends on the type of cabinet and the overall heat capacity of the compression apparatus. To obtain test results which can be compared with each other, it is necessary, in the case of a 24 h test d
41、uration, to reach the steady-state temperature within the specified limits in the interior of the test pieces in not more than 3 h.2 ISO 2014 All rights reservedBS ISO 815-2:2014ISO 815-2:2014(E) 4.1.3 Pair of tongs, for handling the test pieces. 4.1.4 Thickness gauge, with an accuracy of 0,01 mm (s
42、ee ISO 23529:2010, 7.1), having a flat solid base-plate and exerting a pressure of 22 kPa 5 kPa for solid rubber of hardness equal to or greater than 35 IRHD, or a pressure of 10 kPa 2 kPa if the hardness is less than 35 IRHD. For comparative tests, the same dimensions of the circular foot shall be
43、used. NOTE When using a digital gauge, a resolution of 0,001 mm is needed to obtain the required accuracy. 4.1.5 Timing device, for measuring the recovery time, with a precision of 1 s Key 1 test piece 5 lower plate 2 spacer 6 part formed for clamping in a vice 3 nut 7 locating pin 4 upper plate 8 s
44、crew Figure 1 Example of assembly for the determination of compression set ISO 2014 All rights reserved 3BS ISO 815-2:2014ISO 815-2:2014(E) Figure 2 Example of a quick-release mechanism 4.2 Method 2 4.2.1 Compression apparatus, consisting of compression plates, spacer(s) (optional), a thickness gaug
45、e, a temperature sensor, and a device for applying a specified pressure for thickness measurements. The measurement pressure for thickness measurements is the same as that specified in ISO 23529:2010. The compression apparatus shall be capable of applying the compression and maintaining it during th
46、e whole duration of the test, and it shall be possible to keep the apparatus in a low-temperature cabinet at the specified test temperature. Care shall be taken to ensure that there is as little influence on the test as possible by conduction of heat away from the test piece, for example, through me
47、tal parts which are connected with the outside of the low-temperature cabinet. The part of the apparatus with the compression plates and the test piece shall be within the low-temperature cabinet during the whole of the test, but the thickness gauge may be located outside the cabinet. An example of
48、a compression apparatus is shown in Figure 3. It shall be possible to release the compression of the test piece without opening the low-temperature cabinet. 4.2.1.1 Compression plates, comprising a pair of parallel, flat, highly polished chromium-plated steel or highly polished stainless-steel plate
49、s, between the faces of which the test piece is compressed. The plates shall be sufficiently rigid to ensure that, with a test piece under load, no compression plate bends by more than 0,01 mm, and of sufficient size to ensure that the whole of the test piece, when compressed between the plates, remains within the area of the plates. NOTE A surface finish not worse than Ra 0,4 m (see ISO 4287) has been found to be suitable. Such an Ra can be obtained by a grinding or polishing operation
