1、raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI Standards Publication BS ISO 7148-2:2012 Plain bearings Testing of the tribological behaviour of bearing materials Part 2: Testing of polymer-based bearing materialsBS ISO 7148-2:2012 BRITISH STAND
2、ARD National foreword This British Standard is the UK implementation of ISO 7148-2:2012. It supersedes BS ISO 7148-2:1999, which is withdrawn. The UK participation in its preparation was entrusted to T e c h n i c a l C o m m i t t e e M C E / 1 2 , P l a i n b e a r i n g s . A list of organization
3、s 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 responsible for its correct application. The British Standards Institution 2012. Published by BSI Standards Limited 2012l. I
4、SBN 978 0 580 71542 6 ICS 21.100.10 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2012. Amendments issued since publication Date T e x t a f f e c
5、t e dBS ISO 7148-2:2012 ISO 2012 Plain bearings Testing of the tribological behaviour of bearing materials Part 2: Testing of polymer-based bearing materials Paliers lisses Essai du comportement tribologique des matriaux antifriction Partie 2: Essai des matriaux pour paliers base de polymre INTERNAT
6、IONAL STANDARD ISO 7148-2 Second edition 2012-10-01 Reference number ISO 7148-2:2012(E)BS ISO 7148-2:2012ISO 7148-2:2012(E) ii ISO 2012 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2012 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized
7、 in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at 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
8、 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in SwitzerlandBS ISO 7148-2:2012ISO 7148-2:2012(E) ISO 2012 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Normative references 1 3 Symbols, units and abbreviated terms 1 4 Special features for the tribological testing
9、of polymer-based materials 2 5 Test methods . 5 5.1 General . 5 5.2 Test method A Pin-on-disc . 5 5.3 Test method B Block (or pin)-on-ring 6 5.4 Test method C Plain bearing-on-shaft . 7 5.5 Test method D Sphere-on-prism 7 5.6 Test method E Rotation under thrust load 8 6 Test specimens 9 6.1 Data req
10、uired 9 6.2 Polymer-based plain bearing materials (pl) 9 6.3 Materials of mating component . 9 6.4 Dimensions of test specimens . 9 6.5 Preparation of the test specimens .14 7 Test methods and test equipment .15 7.1 General 15 7.2 Test method A Pin-on-disc 15 7.3 Test method B Block-on-ring 16 7.4 T
11、est method C Plain bearing-on-shaft 16 7.5 Test method D Sphere-on-prism .16 7.6 Test method E Rotation under thrust load .17 8 Lubrication 17 8.1 General 17 8.2 Dry (dr) .18 8.3 Grease (gr) .18 8.4 Oil (oi) 18 8.5 Solid lubricant (so) .18 9 Designation .18 10 Test conditions 18 10.1 Environmental c
12、onditions 18 10.2 Mounting of the test specimens 19 10.3 Test variables .19 11 Test procedure .21 11.1 Running-in .21 11.2 Carrying out the tests .21 12 Analysis .21 12.1 General 21 12.2 Test results.22 Annex A (informative) Test report .23 Bibliography .25BS ISO 7148-2:2012ISO 7148-2:2012(E) Forewo
13、rd 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 interested in a subject for which a technic
14、al 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 Electrotechnical Commission (IEC) on all matters of el
15、ectrotechnical 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 adopted by the technical committees are circulated to t
16、he 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 patent rights. ISO shall not be held responsible for id
17、entifying any or all such patent rights. ISO 7148-2 was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 2, Materials and lubricants, their properties, characteristics, test methods and testing conditions. This second edition cancels and replaces the first edition (ISO 714
18、8-2:1999), which has been technically revised. ISO 7148 consists of the following parts, under the general title Plain bearings Testing of the tribological behaviour of bearing materials: Part 1: Testing of bearing metals Part 2: Testing of polymer-based bearing materials iv ISO 2012 All rights rese
19、rvedBS ISO 7148-2:2012INTERNATIONAL ST ANDARD ISO 7148-2:2012(E) Plain bearings Testing of the tribological behaviour of bearing materials Part 2: Testing of polymer-based bearing materials 1 Scope This part of ISO 7148 specifies tribological tests of polymer-based plain bearing materials under spec
20、ified working conditions, i.e. load, sliding velocity and temperature, with and without lubrication. From the test results, data are obtained which indicate the relative tribological behaviour of metal- polymer and polymer-polymer rubbing parts. The purpose of this part of ISO 7148 is to obtain, for
21、 polymer material combinations used in plain bearings, reproducible measured values for friction and wear under specified and exactly-defined test conditions without lubrication (dry surfaces) and with lubrication (boundary lubrication). The test results give useful information for practical applica
22、tion only if all parameters of influence are identical. The more the test conditions deviate from the actual application, the greater the uncertainty of the applicability of the results. 2 Normative references The following referenced documents are indispensable for the application of this document.
23、 For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 527-2, Plastics Determination of tensile properties Part 2: Test conditions for moulding and extrusion plastics ISO 527-3, Plastics Det
24、ermination of tensile properties Part 3: Test conditions for films and sheets ISO 2818, Plastics Preparation of test specimens by machining ISO 4385, Plain bearings Compression testing of metallic bearing materials ISO 6691, Thermoplastic polymers for plain bearings Classification and designation 3
25、Symbols, units and abbreviated terms See Table 1. ISO 2012 All rights reserved 1BS ISO 7148-2:2012ISO 7148-2:2012(E) Table 1 Symbols, units and abbreviated terms Symbol Term Unit A, B, C, D, E Test method - a Sliding distance km dr Dry - f Coefficient of friction; ratio between friction force and no
26、rmal force, i.e.: - F f Friction force N F n Normal force N gr Grease K w Coefficient of wear, volumetric wear rate related to the normal force, i.e.: mm 3 /(Nkm) l w Linear wear as measured by change in distance mm M f Friction moment Nm oi Oil - p Specific force per unit area (force/projected cont
27、act area) N/mm 2 R d,B Compression strength N/mm 2 R d0,2 Compression limit 0,2 % N/mm 2 so Solid lubricant T Specimens temperature near the sliding surface during testing under steady- state conditions C T amb Ambient temperature C T g Glass transition temperature C T lim Maximum permissible temper
28、ature C t Ch Test duration h U Sliding velocity m/s V W Material removed by wear as measured by change in volume mm 3 w l Linear wear rate, i.e.; mm/km w v Volumetric wear rate, i.e.: mm 3 /km Lubricant viscosity mPas 4 Special features for the tribological testing of polymer-based materials Polymer
29、s have a low thermal conductivity and a low melting temperature, so that heat resulting from contact friction may lead to partial melting and hence feign wear. Due to the high thermal expansion of polymers (up to 10 times higher than that of steel) results obtained can be misleading because the test
30、 specimens have expanded under frictional heat. Hence allowance shall be made for the effects of thermal expansion (change of clearance) and thermal conductivity (melting) when assessing the results. Where possible the temperature of both test specimens should be controlled. 2 ISO 2012 All rights re
31、servedBS ISO 7148-2:2012ISO 7148-2:2012(E) Polymers have a glass transition temperature, T g , which depends on their chemical structure. At this temperature, their physical properties and their tribological behaviour may change. Injection-moulded polymer surfaces have different properties from mach
32、ined surfaces. The test specimens shall be tested with the same surface conditions as they have in practical application. Reinforcements and fillers, i.e. fibres, may lead to very strong anisotropy of the material and influence its wear behaviour depending on fibre orientation. The test specimens sh
33、ould have the same fibre orientation as in practical application. In order to avoid stick-slip, the test rig shall be very stiff and shall not be susceptible to vibrations. The tribological behaviour of polymers depends very strongly on the material combination, which part moves and which part remai
34、ns stationary. The test system shall be similar to practical application. Polymers show wear processes that are different from that of metals. There are not only abrasive processes with powder-like wear debris, but also adhesive processes with the creation of transfer layers which may be smooth or r
35、ough. Also ploughing wear and melting or plastic deformation is possible. Therefore, wear cannot be gravimetrically measured in all cases and the wear status shall be judged after the tests (whether the surfaces are fine- or coarse- grained, scored or plucked out, scaled, melted or plastically defor
36、med). Some polymers may show poor repeatability of the results and require repeated testing (i.e. six or more repetitions). The preparation and preparatory treatment (e.g. conditioning, storage, cleaning) of the test specimens can have a high influence on performance. In some thermoplastics, e.g. po
37、lyamides, moisture absorption effects a gradual change in linear dimensions and modifies their mechanical properties. Environmental parameters should, therefore, be controlled in the test array. Moisture absorption prohibits gravimetrical measurement of wear. The more the test conditions deviate fro
38、m the actual application, the greater is the uncertainty of the applicability of the results (see Figures 1 and 2). a) Plain bearing-on-shaft ISO 2012 All rights reserved 3BS ISO 7148-2:2012ISO 7148-2:2012(E) b) Linear guidance system Figure 1 Simulation of real rubbing contacts a) Pin-on-disc b) Bl
39、ock-on-ring c) Sphere-on-prism 4 ISO 2012 All rights reservedBS ISO 7148-2:2012ISO 7148-2:2012(E) d) Rotation under thrust load Sleeve-to-sleeve e) Rotation under thrust load Sleeve-to-plate Figure 2 Simulation under approximated practical testing conditions and model systems 5 Test methods 5.1 Gene
40、ral Different test methods are provided for tests in accordance with this part of ISO 7148 so that the following contact geometries are available. The test methods should correspond to the practical application as closely as possible. 5.2 Test method A Pin-on-disc See Figure 3. ISO 2012 All rights r
41、eserved 5BS ISO 7148-2:2012ISO 7148-2:2012(E) Advantages: basic testing of simple test specimens; testing of tribological properties; no increase of sliding surface area due to wear; initial ranking of materials; simulation of linear guidance system see Figure 1b). Disadvantages: edge of the pin mig
42、ht wipe off lubricant; no injection moulding of the pin with fibre reinforced material; no injection moulding of the disc because of problems with shrinkage. Figure 3 Test method A Pin-on-disc 5.3 Test method B Block (or pin)-on-ring See Figure 4. Advantages: basic testing of simple test specimens;
43、testing of tribological properties; no increase of sliding surface area due to wear; initial ranking of materials; with and without lubrication. Disadvantages: no injection moulding of the block because of problems with shrinkage and fibre orientation; edge of the block might wipe off lubricant; no
44、injection moulding of the disc because of problems with shrinkage. Figure 4 Test method B Block (or pin)-on-ring 6 ISO 2012 All rights reservedBS ISO 7148-2:2012ISO 7148-2:2012(E) 5.4 Test method C Plain bearing-on-shaft See Figure 5. Advantages: best simulation of all possible systems; testing of o
45、riginal or scaled bearings; prediction of practical behaviour; with and without lubrication. Disadvantages: long testing time (accelerated testing might cause excessive frictional heating); difficult alignment of the test bearing; increasing sliding surface area due to wear under boundary lubricatio
46、n. Figure 5 Test method C Plain bearing-on-shaft 5.5 Test method D Sphere-on-prism See Figure 6. Advantages: testing of polymer/polymer or polymer/metal combinations; with and without lubrication (test specimen contains reservoir for lubricant); testing of lubricants interaction with polymers; injec
47、tion-moulded test specimens available; self-adjustment of the alignment of the sliding couple; increasing sliding surface area due to wear under boundary lubrication. Disadvantages: plastic deformation might affect results; increasing sliding surface area due to wear under dry conditions. Figure 6 T
48、est method D Sphere-on-prism ISO 2012 All rights reserved 7BS ISO 7148-2:2012ISO 7148-2:2012(E) 5.6 Test method E Rotation under thrust load See Figure 7. a) E1 Sleeve-to-sleeve b) E2 Sleeve-to-plate Figure 7 Rotation under thrust load Advantages: basic testing of simple specimens; injection-moulded test specimens available; testing of tribological properties; initial ranking of material; no increase of sliding surface area due to wear; continuous sliding between specimens; with and without lubrication. Disadvantages: plastic deformation affects results; shrinkage at sliding surface on
