1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 7148-2:2012Plain bearings Testing of the tribological behaviour of bearing materialsPart 2: Testing of polymer-based bearing materialsBS ISO 7148-2:2012 BRITISH STANDARDNa
2、tional forewordThis 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 It supersedes BS ISO 7148-2:1999, which is withdrawn.The UK participation in its preparation was entrusted to T e c h n i c a l C o m m i t t e e M C E / 1 2 , P l a i n b e a r i n g s .A list of organizations represe
3、nted 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.ISBN 978 0 5
4、80 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 publicationDate T e x t a f f e c t e dBS ISO 71
5、48-2:2012 ISO 2012Plain bearings Testing of the tribological behaviour of bearing materials Part 2: Testing of polymer-based bearing materialsPaliers lisses Essai du comportement tribologique des matriaux antifriction Partie 2: Essai des matriaux pour paliers base de polymreINTERNATIONAL STANDARDISO
6、7148-2Second edition2012-10-01Reference numberISO 7148-2:2012(E)BS ISO 7148-2:2012ISO 7148-2:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any mea
7、ns, 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 officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrighti
8、so.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 7148-2:2012ISO 7148-2:2012(E) ISO 2012 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Symbols, units and abbreviated terms 14 Special features for the tribological testing of polymer-based materials 25 Test meth
9、ods . 55.1 General . 55.2 Test method A Pin-on-disc . 55.3 Test method B Block (or pin)-on-ring 65.4 Test method C Plain bearing-on-shaft . 75.5 Test method D Sphere-on-prism 75.6 Test method E Rotation under thrust load 86 Test specimens 96.1 Data required 96.2 Polymer-based plain bearing materials
10、 (pl) 96.3 Materials of mating component . 96.4 Dimensions of test specimens . 96.5 Preparation of the test specimens . 147 Test methods and test equipment .157.1 General 157.2 Test method A Pin-on-disc 157.3 Test method B Block-on-ring 167.4 Test method C Plain bearing-on-shaft 167.5 Test method D
11、Sphere-on-prism . 167.6 Test method E Rotation under thrust load .178 Lubrication 178.1 General 178.2 Dry (dr) . 188.3 Grease (gr) . 188.4 Oil (oi) 188.5 Solid lubricant (so) . 189 Designation .1810 Test conditions 1810.1 Environmental conditions 1810.2 Mounting of the test specimens 1910.3 Test var
12、iables . 1911 Test procedure .2111.1 Running-in . 2111.2 Carrying out the tests . 2112 Analysis .2112.1 General 2112.2 Test results. 22Annex A (informative) Test report .23Bibliography .25BS ISO 7148-2:2012ISO 7148-2:2012(E)ForewordISO (the International Organization for Standardization) is a worldw
13、ide 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 on th
14、at 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.International Standards are drafted in a
15、ccordance 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 the member bodies for voting. Publication as an International Standard req
16、uires 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 identifying any or all such patent rights.ISO 7148-2 was prepared by Technic
17、al 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 7148-2:1999), which has been technically revised.ISO 7148 consists of the follo
18、wing 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 materialsiv ISO 2012 All rights reservedBS ISO 7148-2:2012INTERNATIONAL STANDARD ISO 7148-2:2012(E)Plain bearings
19、Testing of the tribological behaviour of bearing materials Part 2: Testing of polymer-based bearing materials1 ScopeThis part of ISO 7148 specifies tribological tests of polymer-based plain bearing materials under specified working conditions, i.e. load, sliding velocity and temperature, with and wi
20、thout 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 polymer material combinations used in plain bearings, reproducible measured values
21、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 application only if all parameters of influence are identical. The more the test conditions
22、deviate from the actual application, the greater the uncertainty of the applicability of the results.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the late
23、st 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 plasticsISO 527-3, Plastics Determination of tensile properties Part 3: Test conditions for films and sheetsISO 2818, Pl
24、astics Preparation of test specimens by machiningISO 4385, Plain bearings Compression testing of metallic bearing materialsISO 6691, Thermoplastic polymers for plain bearings Classification and designation3 Symbols, units and abbreviated termsSee Table 1. ISO 2012 All rights reserved 1BS ISO 7148-2:
25、2012ISO 7148-2:2012(E)Table 1 Symbols, units and abbreviated termsSymbol Term UnitA, B, C, D, E Test method -a Sliding distance kmdr Dry -fCoefficient of friction; ratio between friction force and normal force, i.e.: fFFfn=-FfFriction force NFnNormal force Ngr Grease KwCoefficient of wear, volumetri
26、c wear rate related to the normal force, i.e.:KVFwFwwnvn=a=mm3/(Nkm)lwLinear wear as measured by change in distance mmMfFriction moment Nmoi Oil -pSpecific force per unit area (force/projected contact area) N/mm2Rd,BCompression strength N/mm2Rd0,2Compression limit 0,2 % N/mm2so Solid lubricant TSpec
27、imens temperature near the sliding surface during testing under steady-state conditionsCTambAmbient temperature CTgGlass transition temperature CTlimMaximum permissible temperature CtChTest duration hU Sliding velocity m/sVWMaterial removed by wear as measured by change in volume mm3wlLinear wear ra
28、te, i.e.; wlalw= mm/kmwvVolumetric wear rate, i.e.: wVavw= mm3/km Lubricant viscosity mPas4 Special features for the tribological testing of polymer-based materialsPolymers have a low thermal conductivity and a low melting temperature, so that heat resulting from contact friction may lead to partial
29、 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 specimens have expanded under frictional heat. Hence allowance shall be made for the effects of thermal expansion (change of cle
30、arance) and thermal conductivity (melting) when assessing the results. Where possible the temperature of both test specimens should be controlled.2 ISO 2012 All rights reservedBS ISO 7148-2:2012ISO 7148-2:2012(E)Polymers have a glass transition temperature, Tg, which depends on their chemical struct
31、ure. At this temperature, their physical properties and their tribological behaviour may change.Injection-moulded polymer surfaces have different properties from machined surfaces. The test specimens shall be tested with the same surface conditions as they have in practical application.Reinforcement
32、s 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 should have the same fibre orientation as in practical application.In order to avoid stick-slip, the test rig shall be very stiff and sha
33、ll not be susceptible to vibrations.The tribological behaviour of polymers depends very strongly on the material combination, which part moves and which part remains stationary. The test system shall be similar to practical application.Polymers show wear processes that are different from that of met
34、als. 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 rough. Also ploughing wear and melting or plastic deformation is possible. Therefore, wear cannot be gravimetrically measured in all cases
35、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 deformed).Some polymers may show poor repeatability of the results and require repeated testing (i.e. six or more repetitions).The preparation
36、and preparatory treatment (e.g. conditioning, storage, cleaning) of the test specimens can have a high influence on performance.In some thermoplastics, e.g. polyamides, moisture absorption effects a gradual change in linear dimensions and modifies their mechanical properties. Environmental parameter
37、s should, therefore, be controlled in the test array. Moisture absorption prohibits gravimetrical measurement of wear.The more the test conditions deviate from the actual application, the greater is the uncertainty of the applicability of the results (see Figures 1 and 2).a) Plain bearing-on-shaft I
38、SO 2012 All rights reserved 3BS ISO 7148-2:2012ISO 7148-2:2012(E)b) Linear guidance systemFigure 1 Simulation of real rubbing contactsa) Pin-on-discb) Block-on-ringc) Sphere-on-prism4 ISO 2012 All rights reservedBS ISO 7148-2:2012ISO 7148-2:2012(E)d) Rotation under thrust load Sleeve-to-sleevee) Rot
39、ation under thrust load Sleeve-to-plateFigure 2 Simulation under approximated practical testing conditions and model systems5 Test methods5.1 GeneralDifferent test methods are provided for tests in accordance with this part of ISO 7148 so that the following contact geometries are available. The test
40、 methods should correspond to the practical application as closely as possible.5.2 Test method A Pin-on-discSee Figure 3. ISO 2012 All rights reserved 5BS ISO 7148-2:2012ISO 7148-2:2012(E)Advantages: basic testing of simple test specimens; testing of tribological properties; no increase of sliding s
41、urface area due to wear; initial ranking of materials; simulation of linear guidance system see Figure 1b).Disadvantages: edge of the pin might wipe off lubricant; no injection moulding of the pin with fibre reinforced material; no injection moulding of the disc because of problems with shrinkage.Fi
42、gure 3 Test method A Pin-on-disc5.3 Test method B Block (or pin)-on-ringSee Figure 4.Advantages: basic testing of simple test specimens; testing of tribological properties; no increase of sliding surface area due to wear; initial ranking of materials; with and without lubrication.Disadvantages: no i
43、njection moulding of the block because of problems with shrinkage and fibre orientation; edge of the block might wipe off lubricant; no injection moulding of the disc because of problems with shrinkage.Figure 4 Test method B Block (or pin)-on-ring6 ISO 2012 All rights reservedBS ISO 7148-2:2012ISO 7
44、148-2:2012(E)5.4 Test method C Plain bearing-on-shaftSee Figure 5.Advantages: best simulation of all possible systems; testing of original or scaled bearings; prediction of practical behaviour; with and without lubrication.Disadvantages: long testing time (accelerated testing might cause excessive f
45、rictional heating); difficult alignment of the test bearing; increasing sliding surface area due to wear under boundary lubrication.Figure 5 Test method C Plain bearing-on-shaft5.5 Test method D Sphere-on-prismSee Figure 6.Advantages: testing of polymer/polymer or polymer/metal combinations; with an
46、d without lubrication (test specimen contains reservoir for lubricant); testing of lubricants interaction with polymers; injection-moulded test specimens available; self-adjustment of the alignment of the sliding couple; increasing sliding surface area due to wear under boundary lubrication.Disadvan
47、tages: plastic deformation might affect results; increasing sliding surface area due to wear under dry conditions.Figure 6 Test 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 loadSee Figure 7.a) E1 Sleeve-to-sleeveb)
48、 E2 Sleeve-to-plateFigure 7 Rotation under thrust loadAdvantages: 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; wit
49、h and without lubrication.Disadvantages: plastic deformation affects results; shrinkage at sliding surface on injection-moulded specimens affects results.8 ISO 2012 All rights reservedBS ISO 7148-2:2012ISO 7148-2:2012(E)6 Test specimens6.1 Data requiredFor one series of tests, several specimens of one material shall be from the same batch, with uniform state aft
