1、raising standards worldwide NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BSI Standards Publication BS ISO 7148-1:2012 Plain bearings Testing of the tribological behaviour of bearing materials Part 1: Testing of bearing metalsBS ISO 7148-1:2012 BRITISH STANDARD National fore
2、word This 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 It supersedes BS ISO 7148-1:1999 which is withdrawn.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 r
3、equest 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 2012 ISBN 978 0 580 71541 9 ICS 21.100.10 Compliance with a
4、British Standard 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 publication Date T e x t a f f e c t e dBS ISO 7148-1:2012 ISO 2012 Plain bearings Testi
5、ng of the tribological behaviour of bearing materials Part 1: Te s t i n g o f b e a r i n g m e t a l s Paliers lisses Essai du comportement tribologique des matriaux antifriction Partie 1: Essai des matriaux mtalliques INTERNATIONAL STANDARD ISO 7148-1 Third edition 2012-10-01 Reference number ISO
6、 7148-1:2012(E)BS ISO 7148-1:2012ISO 7148-1:2012(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 in any form or by any means, electronic or mechanical, including photoc
7、opying 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 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switz
8、erlandBS ISO 7148-1:2012ISO 7148-1:2012(E) ISO 2012 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Normative references 1 3 Symbols and units . 1 4 Special features for the tribological testing of metallic bearing materials .2 5 Test methods . 2 5.1 Test method A Pin-on-disc . 2 5.2
9、 Test method B Block-on-ring . 3 5.3 Test method C Rotation under thrust load 4 6 Test specimens 5 6.1 Disc 5 6.2 Ring . 5 6.3 Pin 5 6.4 Block. 5 6.5 Sleeve . 5 6.6 Plate 6 6.7 Preparation of the test specimens 6 7 Test methods and test equipment 7 8 Lubrication . 7 9 Designation 7 10 Test condition
10、s . 7 11 Test procedure 8 Annex A (informative) Test report 9 Bibliography .11BS ISO 7148-1:2012ISO 7148-1:2012(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standar
11、ds 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 that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take
12、 part in the work. ISO collaborates closely with the International Electrotechnical 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
13、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 requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility
14、 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 7148-1 was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 2, Materials and lubricants, their properties,
15、characteristics, test methods and testing conditions. This third edition cancels 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 ma
16、terials: Part 1: Testing of bearing metals Part 2: Testing of polymer-based bearing materials. iv ISO 2012 All rights reservedBS ISO 7148-1:2012INTERNATIONAL ST ANDARD ISO 7148-1:2012(E) Plain bearings Testing of the tribological behaviour of bearing materials Part 1: Testing of bearing metals 1 Sco
17、pe This part of ISO 7148 specifies tribological tests of metallic bearing materials for 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 compa
18、red with that of other combinations, thus facilitating the selection of a bearing material 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
19、 to vary from one test facility to another. The test results give useful information for 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 Norma
20、tive references The following referenced documents are indispensable for the application 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 Compress
21、ion testing of metallic bearing materials 3 Symbols and units See Table 1. Table 1 Symbols and units Symbol Term Unit A, B, C Test method a Sliding distance km A 5 Elongation at fracture % f Coefficient of friction; ratio between friction force and normal force, i.e.: F f Friction force N F n Normal
22、 force N K A Overlap ratio (area of contact divided by area of wear track) ISO 2012 All rights reserved 1BS ISO 7148-1:2012ISO 7148-1:2012(E) Symbol Term Unit K w Coefficient of wear, volumetric wear rate related to the normal force, i.e.: mm 3 /(N km) l w Linear wear as measured by change in distan
23、ce mm m w Mass of material removed by wear g Ra Surface roughness m R d0,2 Compression limit 0,2 % N/mm 2 R m Tensile strength N/mm 2 R p0,2 0,2 % Proof stress N/mm 2 T Specimens temperature near the sliding surface during testing under steady- state conditions C T amb Ambient temperature C T L Lubr
24、icant temperature 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 mPa s 4 Special features for the tribological testing of metallic bearing m
25、aterials Plain bearings made of metallic materials usually require lubrication (e.g. oil or grease) to ensure a low rate of friction 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 beari
26、ng are always fully separated by a film of lubricant. Under such conditions, friction depends on the rheological properties of the 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 li
27、kely. This may be during the starting or running down phase of a hydrodynamic plain bearing or when high loads, low sliding velocities, poor lubrication or oscillating movements prevent hydrodynamic action. 5 Test methods 5.1 Test method A Pin-on-disc Figure 1 shows a schematic drawing of a disc and
28、 pin assembly. Table 1 (continued) 2 ISO 2012 All rights reservedBS ISO 7148-1:2012ISO 7148-1:2012(E) Key 1 disc or ring 2 pin or block Figure 1 Pin-on-disc test method 5.2 Test method B Block-on-ring Figure 2 shows a schematic drawing of a block and ring assembly. ISO 2012 All rights reserved 3BS I
29、SO 7148-1:2012ISO 7148-1:2012(E) Key 1 disc or ring 2 pin or block Figure 2 Block-on-ring test method 5.3 Test method C Rotation under thrust load Figure 3 shows schematic drawings of a sleeve-to-sleeve and sleeve-to-plate assembly. a) C1 Sleeve-to-sleeve 4 ISO 2012 All rights reservedBS ISO 7148-1:
30、2012ISO 7148-1:2012(E) b) C2 Sleeve-to-plate Figure 3 Rotation under thrust load 6 Test specimens 6.1 Disc The disc shall have the following preferred dimensions: diameter, d 1 : 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 Ring Th
31、e ring shall have an outside diameter, d 1 , of 40 mm to 80 mm and the width, b 1 , of the ring shall exceed the width, b 2 , of the block. 6.3 Pin The pin shall preferably have a diameter, d 2 , of 3 mm to 10 mm. 6.4 Block The cross-section of the block shall be 5 mm to 10 mm high and 5 mm to 10 mm
32、 wide. 6.5 Sleeve The 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 7148-1:2012(E) Dimensions in millimetres Figure 4 Dimensions of sleeve 6.6 Plate The plate can be made by machining. The pref
33、erred basic dimensions of the sleeve are shown in Figure 5. Dimensions in millimetres Figure 5 Dimensions of plate 6.7 Preparation of the test specimens After preparing the test surfaces with the same machining methods in order to obtain a suitable surface finish (similar to the application which is
34、 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; 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
35、and test equipment The pin, block, sleeve or plate, made of the bearing materials, is pressed with a known normal force, F n , against the rotating specimen (disc, ring or sleeve) made from the material of the mating component. In practice, surfaces with cylindrical surface curvature (journal bearin
36、gs) 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 line contact (radius of the block to be larger than the radius of the ring). The linear wear should not excee
37、d 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-than-normal atmosphere, use shall be made of either a sufficiently airtight chamber or a high rate of gas flow.
38、 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 supplied to the sliding track. Vibrations in the loading mechanism, which can cause undefined variations in the a
39、pplied normal force, shall be avoided. 8 Lubrication Oil or grease lubrication shall be used depending on the practical application. The contact surface between the pin, block, sleeve or plate and the disc, ring or sleeve shall be completely filled with lubricant. When oil lubrication is used, it is
40、 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 is not dependent upon the lubricant flow rate. The oil temperature shall be kept constant. NOTE Test r
41、esults can vary widely depending on the lubricant used. 9 Designation EXAMPLE The testing of the tribological behaviour of metallic bearing materials according to test method A (pin-on-disc) is designated as follows:Test ISO 7148-1 -A 10 Test conditions When testing different material/lubricant comb
42、inations 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 variables, shall all be kept constant during the test programme: initial surface roughness, Ra, of the s
43、pecimens; normal force, F n ; lubricant temperature, T L ; sliding distance, a; sliding velocity, U; ISO 2012 All rights reserved 7BS ISO 7148-1:2012ISO 7148-1:2012(E) overlap ratio, K A . In order to simulate friction and wear in a given plain bearing, realistic values of surface roughness, normal
44、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, and constant for each test. At prolonged running under conditions of boundary lubrication
45、, 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 materials for applications in which the plain bearing is expected to run under conditions of
46、 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 completed, the roughness of the mating material surface, Ra, should be measured and given wit
47、h the test results. A newly prepared surface shall be used for each test. As far as the normal force, F n , is concerned, the most widely accepted compromise is to make the maximum force per unit pin, block or sleeve area equal to the force per unit projected bearing area (specific load) of the prac
48、tical 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 generate specific loads (normal force divided by projected contact area) ranging up
49、 to one third of the 0,2 % proof stress, R p0,2 , or one third of the 0,2 % compression limit, R d0,2 , (as specified in ISO 4385) at the temperature of the application. In practice, this value is generally considered to be the maximum permissible force per unit projected area for each material in highly loaded plain bearings under boundary lubrication conditions. For T L , a temperature
