1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 7148-1:2012Plain bearings Testing of the tribological behaviour of bearing materialsPart 1: Testing of bearing metalsBS ISO 7148-1:2012 BRITISH STANDARDNational forewordTh
2、is British Standard is the UK implementation of ISO 7148-1:2012. It supersedes BS ISO 7148-1:1999 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee MCE/12, Plain bearings.A list of organizations represented on this committee can be obtained on request to
3、 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 2012ISBN 978 0 580 71541 9 ICS 21.100.10 Compliance with a British Stan
4、dard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2012.Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 7148-1:2012 ISO 2012Plain bearings Testing of the tribol
5、ogical behaviour of bearing materials Part 1: Testing of bearing metalsPaliers lisses Essai du comportement tribologique des matriaux antifriction Partie 1: Essai des matriaux mtalliquesINTERNATIONAL STANDARDISO 7148-1Third edition 2012-10-01Reference number ISO 7148-1:2012(E)BS ISO 7148-1:2012ISO 7
6、148-1:2012(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 means, electronic or mechanical, including photocopying and microfilm, without permission
7、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 copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 7148-1:2012ISO 7148-1:2012(E) ISO 2
8、012 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Symbols and units . 14 Special features for the tribological testing of metallic bearing materials . 25 Test methods . 25.1 Test method A Pin-on-disc . 25.2 Test method B Block-on-ring . 35.3 Test method C Rotati
9、on under thrust load 46 Test specimens 56.1 Disc 56.2 Ring . 56.3 Pin 56.4 Block. 56.5 Sleeve . 56.6 Plate 66.7 Preparation of the test specimens 67 Test methods and test equipment 78 Lubrication . 79 Designation 710 Test conditions . 711 Test procedure 8Annex A (informative) Test report 9Bibliograp
10、hy .11BS ISO 7148-1:2012ISO 7148-1:2012(E)ForewordISO (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 b
11、ody 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 International Electro
12、technical 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 adopted by
13、 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 patent righ
14、ts. ISO shall not be held responsible for identifying any or all such patent rights.ISO 7148-1 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 third edition cancel
15、s and replaces the second edition (ISO 7148-1:1999), 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 bear
16、ing materials.iv ISO 2012 All rights reservedBS ISO 7148-1:2012INTERNATIONAL STANDARD ISO 7148-1:2012(E)Plain bearings Testing of the tribological behaviour of bearing materials Part 1: Testing of bearing metals1 ScopeThis part of ISO 7148 specifies tribological tests of metallic bearing materials f
17、or plain bearings under conditions of boundary lubrication.The test procedures described in this part of ISO 7148 enable the friction and wear behaviour of bearing material/mating/lubricant combinations to be compared with that of other combinations, thus facilitating the selection of a bearing mate
18、rial for running repeatedly or for long periods under conditions of boundary lubrication, low speed and continuous sliding. Owing to differences in test conditions, measured friction and wear values can be expected to vary from one test facility to another.The test results give useful information fo
19、r practical application 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 referencesThe following referenced documents are indispensable for the application
20、of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 4385, Plain bearings Compression testing of metallic bearing materials3 Symbols and unitsSee Table 1.Table 1 Symbols an
21、d unitsSymbol Term UnitA, B, C Test method a Sliding distance kmA5Elongation at fracture %fCoefficient of friction; ratio between friction force and normal force, i.e.: fFF=fnFfFriction force NFnNormal force NKAOverlap ratio (area of contact divided by area of wear track) ISO 2012 All rights reserve
22、d 1BS ISO 7148-1:2012ISO 7148-1:2012(E)Symbol Term UnitKwCoefficient of wear, volumetric wear rate related to the normal force, i.e.:KVFwFwwnvn=a=mm3/(N km)lwLinear wear as measured by change in distance mmmwMass of material removed by wear gRa Surface roughness mRd0,2Compression limit 0,2 % N/mm2Rm
23、Tensile strength N/mm2Rp0,20,2 % Proof stress N/mm2TSpecimens temperature near the sliding surface during testing under steady-state conditionsCTambAmbient temperature CTLLubricant temperature CtChTest duration hU Sliding velocity m/sVwMaterial removed by wear as measured by change in volume mm3wlLi
24、near wear rate, i.e.: wlalw= mm/kmwvVolumetric wear rate, i.e.: wVavw= mm3/km Lubricant viscosity mPa s4 Special features for the tribological testing of metallic bearing materialsPlain bearings made of metallic materials usually require lubrication (e.g. oil or grease) to ensure a low rate of frict
25、ion and wear.If possible, lubricated plain bearings should be designed to run under hydrodynamic conditions, where the sliding surfaces of the journal and the plain bearing are always fully separated by a film of lubricant. Under such conditions, friction depends on the rheological properties of the
26、 lubricant, and wear normally does not occur.If hydrodynamic operation cannot be ensured, boundary lubrication prevails and wear of the bearing and mating material is likely. This may be during the starting or running down phase of a hydrodynamic plain bearing or when high loads, low sliding velocit
27、ies, poor lubrication or oscillating movements prevent hydrodynamic action.5 Test methods5.1 Test method A Pin-on-discFigure 1 shows a schematic drawing of a disc and pin assembly.Table 1 (continued)2 ISO 2012 All rights reservedBS ISO 7148-1:2012ISO 7148-1:2012(E)Key1 disc or ring2 pin or blockFigu
28、re 1 Pin-on-disc test method5.2 Test method B Block-on-ringFigure 2 shows a schematic drawing of a block and ring assembly. ISO 2012 All rights reserved 3BS ISO 7148-1:2012ISO 7148-1:2012(E)Key1 disc or ring2 pin or blockFigure 2 Block-on-ring test method5.3 Test method C Rotation under thrust loadF
29、igure 3 shows schematic drawings of a sleeve-to-sleeve and sleeve-to-plate assembly.a) C1 Sleeve-to-sleeve4 ISO 2012 All rights reservedBS ISO 7148-1:2012ISO 7148-1:2012(E)b) C2 Sleeve-to-plateFigure 3 Rotation under thrust load6 Test specimens6.1 DiscThe disc shall have the following preferred dime
30、nsions: diameter, d1: 40 mm to 110 mm; width b: 8 mm to 12 mm.The diameter of the sliding track shall be noted in the test report.6.2 RingThe ring shall have an outside diameter, d1, of 40 mm to 80 mm and the width, b1, of the ring shall exceed the width, b2, of the block.6.3 PinThe pin shall prefer
31、ably have a diameter, d2, of 3 mm to 10 mm.6.4 BlockThe cross-section of the block shall be 5 mm to 10 mm high and 5 mm to 10 mm wide.6.5 SleeveThe sleeve can be made by machining. The preferred basic dimensions of the sleeve are shown in Figure 4. ISO 2012 All rights reserved 5BS ISO 7148-1:2012ISO
32、 7148-1:2012(E)Dimensions in millimetresFigure 4 Dimensions of sleeve6.6 PlateThe plate can be made by machining. The preferred basic dimensions of the sleeve are shown in Figure 5.Dimensions in millimetresFigure 5 Dimensions of plate6.7 Preparation of the test specimensAfter preparing the test surf
33、aces with the same machining methods in order to obtain a suitable surface finish (similar to the application which is to be simulated), the specimens shall be thoroughly cleaned. An example of a cleaning method is: cleaning with alcohol, e.g. ultrasonic bath; drying in hot air; rinsing with hexane;
34、 drying in a drying stove at 110 C.6 ISO 2012 All rights reservedBS ISO 7148-1:2012ISO 7148-1:2012(E)7 Test methods and test equipmentThe pin, block, sleeve or plate, made of the bearing materials, is pressed with a known normal force, Fn, against the rotating specimen (disc, ring or sleeve) made fr
35、om the material of the mating component.In practice, surfaces with cylindrical surface curvature (journal bearings) are also tested by test method B. If they are multilayer materials, there are two alternatives:a) adapt the radius of the ring to that of the block (see Figure 2);b) begin testing with
36、 line contact (radius of the block to be larger than the radius of the ring).The linear wear should not exceed the thickness of the surface bearing material layer. For thin layers, test method A (pin-on-disc) and test method C (thrust rotation) are preferred.If tests are performed under an other-tha
37、n-normal atmosphere, use shall be made of either a sufficiently airtight chamber or a high rate of gas flow.Equipment for the continuous measurement of friction and wear shall be available.If grease lubrication is to be used, the equipment shall be such that sufficient grease is continuously supplie
38、d to the sliding track.Vibrations in the loading mechanism, which can cause undefined variations in the applied normal force, shall be avoided.8 LubricationOil or grease lubrication shall be used depending on the practical application. The contact surface between the pin, block, sleeve or plate and
39、the disc, ring or sleeve shall be completely filled with lubricant.When oil lubrication is used, it is preferable for the specimens to be completely immersed in the oil. Spray lubrication may also be used, assuming that the volume of the lubricant supplied is sufficient to ensure that the wear rate
40、is not dependent upon the lubricant flow rate. The oil temperature shall be kept constant.NOTE Test results can vary widely depending on the lubricant used.9 DesignationEXAMPLE The testing of the tribological behaviour of metallic bearing materials according to test method A (pin-on-disc) is designa
41、ted as follows:Test ISO 7148-1 -A10 Test conditionsWhen testing different material/lubricant combinations comparatively, the method of machining and finishing the pin, block, sleeve or plate (bearing material) and the disc, ring or sleeve (mating material), and the following independent test variabl
42、es, shall all be kept constant during the test programme: initial surface roughness, Ra, of the specimens; normal force, Fn; lubricant temperature, TL; sliding distance, a; sliding velocity, U; ISO 2012 All rights reserved 7BS ISO 7148-1:2012ISO 7148-1:2012(E) overlap ratio, KA.In order to simulate
43、friction and wear in a given plain bearing, realistic values of surface roughness, normal force, oil temperature and a sufficiently long sliding distance should be chosen.When materials are being evaluated for specific applications, it is important that the surfaces be typical for that application,
44、and constant for each test.At prolonged running under conditions of boundary lubrication, the roughness of the mating material surface can change gradually as a result of contact with the bearing material. This, in turn, may lead to change in the wear rate of the bearing material. In evaluating mate
45、rials for applications in which the plain bearing is expected to run under conditions of boundary lubrication for appreciable periods of time, this can be taken into account by performing a long-term test, measuring the wear volume as a function of the sliding distance. After the test has been compl
46、eted, the roughness of the mating material surface, Ra, should be measured and given with the test results. A newly prepared surface shall be used for each test.As far as the normal force, Fn, is concerned, the most widely accepted compromise is to make the maximum force per unit pin, block or sleev
47、e area equal to the force per unit projected bearing area (specific load) of the practical application.When comparing material/lubricant combinations in which the bearing materials have different mechanical properties and load capacities, the test may be carried out with values of normal force which
48、 generate specific loads (normal force divided by projected contact area) ranging up to one third of the 0,2 % proof stress, Rp0,2, or one third of the 0,2 % compression limit, Rd0,2, (as specified in ISO 4385) at the temperature of the application. In practice, this value is generally considered to
49、 be the maximum permissible force per unit projected area for each material in highly loaded plain bearings under boundary lubrication conditions.For TL, a temperature corresponding to the highest temperature which is expected to occur in practice shall be chosen. The sliding velocity, U, shall be so low that the system does not reach hydrodynamic conditions.If the friction and wear behaviour of a bearing material/mating/lubricant combination is to be compared with other combi
