1、BSI Standards PublicationBS ISO 18517:2015Rubber, vulcanized orthermoplastic Hardnesstesting Introduction andguideBS ISO 18517:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18517:2015. It supersedes BS ISO 18517:2005 which is withdrawn.The UK participati
2、on 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 a contract. Users are responsib
3、le for its correct application. The British Standards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 85587 0ICS 83.060Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Poli
4、cy and Strategy Committee on 30 April 2015.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 18517:2015 ISO 2015Rubber, vulcanized or thermoplastic Hardness testing Introduction and guideCaoutchouc vulcanis ou thermoplastique Essai de duret Introduction et guideINTERNA
5、TIONAL STANDARDISO18517Second edition2015-04-01Reference numberISO 18517:2015(E)BS ISO 18517:2015ISO 18517:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise i
6、n 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 at the address below or ISOs member body in the country of the requester.ISO copyright officeCase pos
7、tale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 18517:2015ISO 18517:2015(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Indentation hardness 25 Types of hardness test 26 Significanc
8、e 37 Uses of hardness tests . 38 Choice of methods . 39 Test piece 410 Standard hardness blocks. 411 Comparison of hardness scales . 4Bibliography 5 ISO 2015 All rights reserved iiiContents PageBS ISO 18517:2015ISO 18517:2015(E)ForewordISO (the International Organization for Standardization) is a wo
9、rldwide 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 interested in a subject for which a technical committee has been established has the right to be represented o
10、n that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this
11、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 documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Dire
12、ctives, 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 responsible for identifying any or all such patent rights. Details of any patent rights identified during the develo
13、pment 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 for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO sp
14、ecific 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 URL: Foreword Supplementary information .The committee responsible for this document is ISO/TC 45, Rubber and r
15、ubber products, Subcommittee SC 2, Testing and analysis.This second edition cancels and replaces the first edition (ISO 18517:2005), which has been technically revised.iv ISO 2015 All rights reservedBS ISO 18517:2015Rubber, vulcanized or thermoplastic Hardness testing Introduction and guide1 ScopeTh
16、is International Standard provides guidance on the determination of the hardness of vulcanized and thermoplastic rubbers.It is intended to provide an understanding of the significance of hardness as a material property and to assist in the selection of an appropriate test method.2 Normative referenc
17、esThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 48
18、, Rubber, vulcanized or thermoplastic Determination of hardness (hardness between 10 IRHD and 100 IRHD)ISO 7267-1, Rubber-covered rollers Determination of apparent hardness Part 1: IRHD methodISO 7267-2, Rubber-covered rollers Determination of apparent hardness Part 2: Shore-type durometer methodISO
19、 7267-3, Rubber-covered rollers Determination of apparent hardness Part 3: Pusey and Jones methodISO 7619-1, Rubber, vulcanized or thermoplastic Determination of indentation hardness Part 1: Durometer method (Shore hardness)ISO 7619-2, Rubber, vulcanized or thermoplastic Determination of indentation
20、 hardness Part 2: IRHD pocket meter methodISO 18898, Rubber Calibration and verification of hardness testersISO 27588, Rubber, vulcanized or thermoplasticDetermination of dead-load hardness using the very low rubber hardness (VLRH) scale3 Terms and definitionsFor the purposes of this document, the f
21、ollowing terms and definitions apply.3.1international rubber hardness degreesIRHDhardness scale chosen so that “0” represents the hardness of material having a Youngs modulus of zero and “100” represents the hardness of a material of infinite Youngs modulusNote 1 to entry: The following conditions a
22、re fulfilled over most of the normal range of hardness:a) one international rubber hardness degree always represents approximately the same proportionate difference in the Youngs modulus;b) for highly elastic rubbers, the IRHD and Shore A durometer scales are comparable.INTERNATIONAL STANDARD ISO 18
23、517:2015(E) ISO 2015 All rights reserved 1BS ISO 18517:2015ISO 18517:2015(E)3.2standard hardnessShardness, in international rubber hardness degrees, obtained using the procedures described in ISO 48 on test pieces of the standard thickness and not less than the minimum lateral dimensions specified3.
24、3apparent hardnesshardness, in international rubber hardness degrees, obtained using the procedures described in ISO 48 on test pieces of non-standard dimensions4 Indentation hardnessThe term hardness when applied to rubbers refers to a measure of stiffness obtained from an indentation test. An inde
25、ntor is pressed into the rubber under a given force and the resulting indentation measured as illustrated in Figure 1. In contrast to some methods for other materials, the indentation is measured with the load applied.In most tests, the indentor is surrounded by a foot which rests on the test piece
26、under a given force. In dead-load tests (see Clause 5), the measured indentation is the difference between the indentation caused by a small initial force and that caused by a larger final force.1234Key1 weight or spring to apply force2 indentor3 pressure foot4 test pieceFigure 1 Principle of hardne
27、ss test5 Types of hardness testDistinction is made between dead-load tests, where the indenting force is produced by a weight, and so-called durometers or pocket hardness meters, where the indenting force is applied by a spring.Dead-load methods using a ball indentor with hardness expressed in inter
28、national rubber hardness degrees (IRHD) are specified in ISO 48. This hardness scale is based on the relationship defined in 3.1 and a probit curve relating log10(modulus) to the hardness in IRHD. This results in a scale from 0 to 100 for infinitely soft to infinitely rigid materials. The definition
29、 of IRHD was chosen to give reasonable agreement with the Shore A scale described below.The “normal” dead-load method is intended for use with rubbers in the range 35 IRHD to 85 IRHD and there are modifications for low-hardness and high-hardness rubbers. Method L covers the hardness range from 10 IR
30、HD to 35 IRHD and method H covers the range from 85 IRHD to 100 IRHD. The micro 2 ISO 2015 All rights reservedBS ISO 18517:2015ISO 18517:2015(E)dead-load method is for use on thin test pieces and uses an indentor with diameter one-sixth of that for the “normal” method.ISO 48 also specifies modified
31、procedures for use on curved test pieces, with the result being expressed as apparent hardness.A dead-load method for very soft materials using the very low rubber hardness scale (VLRH) is specified in ISO 27588. This covers a range from about 30 IRHD to below 10 IRHD and the relation between VLRH a
32、nd depth of indentation is linear.For rubber rollers, the Pusey and Jones dead-load instrument is specified in ISO 7267-3 in addition to the ISO 48 and durometer methods in ISO 7267-1 and ISO 7267-2, respectively.Durometers were originally intended to be hand-held but are now often mounted on a stan
33、d with a weight to apply the correct foot pressure. The best known are the Shore gauges, of which there are several different types to cover a range of materials, and which have been produced by a number of manufacturers. Shore A scale durometers for rubbers in the normal hardness range and D scale
34、durometers for hard materials are standardized in ISO 7619-1 together with a micro instrument designated AM and an instrument for soft materials designated AO. The type A uses a truncated cone indentor, types D and AM use a radiused cone, while type AO uses a ball indentor. ISO 7619-2 specifies a po
35、cket meter with a ball indentor designed to read in the IRHD scale.6 SignificanceIn principle, hardness can be related to the modulus of the rubber and empirical formulae can be found in textbooks. A relationship for ball indentation is given in ISO 48 together with graphs of hardness against log(mo
36、dulus). The relationship is only valid for a perfectly elastic rubber, and in practice, can only be considered as approximate.Because of the tenuous relation with Youngs or shear modulus, hardness cannot be considered as a fundamental material property. However, because of the simplicity and cheapne
37、ss of hardness testing together with its essentially non-destructive nature, hardness is universally used as a convenient measure of stiffness.A limitation which is not always appreciated is the discrimination and precision obtainable. Generally, the best that can be achieved is 1 IRHD which transla
38、tes to the order of 4 % modulus in the middle of the scale and 16 % at very low and high hardnesses.7 Uses of hardness testsHardness is a measure of stiffness or modulus which is an important property of rubbers in almost all applications. Its enormous popularity is due to its practical simplicity,
39、versatility in terms of the test piece required, cheapness, and non-destructive nature. Because of this, it is universally used as a quality control test for trouble shooting, as a classification parameter for both compounds and products and as a requirement in material and product specifications. H
40、ardness is widely used as a convenient, non-destructive measure of the state and uniformity of cure of a range of vulcanized products. It can also be used to track ageing, contamination and porosity, and so is suitable for diagnostic purposes.8 Choice of methodsWhen a portable, hand-held instrument
41、is needed, for example for testing products, then a spring-loaded durometer or pocket hardness meter is used. The type A durometer is by far the most popular, but the type AO and the IRHD pocket meter have the advantage of a ball indentor which is less prone to damage than a truncated cone. The IRHD
42、 pocket hardness meter also has a very low variation in spring force over the hardness range and the results correspond directly to those obtained with dead-load instruments. For very hard rubbers and thin test pieces, types D and AM, respectively, are appropriate. The Shore D scale is usually assoc
43、iated with plastics materials, but is in common use for ISO 2015 All rights reserved 3BS ISO 18517:2015ISO 18517:2015(E)harder thermoplastic elastomers and ebonite and is sometimes preferred over Shore A and IRHD scales for rubbers over 90 IRHD.NOTE Durometers have been produced with a built-in devi
44、ce that guarantees the application of the correct foot pressure regardless of the force applied by the operator.The dead-load methods are intended to be the preferred approach for standard test pieces in the laboratory, the micro dead-load method being used where only thin pieces of material are ava
45、ilable. The high and low hardness scales are intended to improve the discrimination at the extremes of the scale, but it has been shown that, for the high scale at least, there is no advantage (for further details, see Reference 1). The VLRH method is preferred for very soft materials.The rationale
46、for using the dead-load instruments is that, a weight gives a constant force and is more stable than a spring. A systematic evaluation of the parameters affecting precision has shown that the dead-load methods are superior in this respect (for further details, see Reference 2). However, many workers
47、 prefer to use the Shore-type durometers on a stand (so they are no longer portable).9 Test pieceIn practice, hardness measurements are made on test pieces and products of various shapes and sizes, particularly when using hand-held durometers. The results obtained are very dependent on test piece di
48、mensions, particularly thickness, and hence it is essential that only the standard test pieces are used to obtain comparative results. Results on non-standard test pieces are termed apparent hardness in ISO 48.The main limitation of apparent hardness measurements is that the results are likely to di
49、ffer from those made on standard test pieces and are only comparable with tests made in the same way using the same geometry. When no micro instrument is available for testing thin material, several plies can be used to obtain a satisfactory test piece thickness, but again, results might vary from those obtained with standard test pieces.10 Standard hardness blocksHardness testers should be calibrated in accordance with ISO 18898, but sets of standard reference blocks are available which are very useful for
