1、July 2014Translation by DIN-Sprachendienst.English price group 14No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 21
2、.100.10!%7H3“2203716www.din.deDDIN ISO 7148-2Plain bearings Testing of the tribological behaviour of bearing materials Part 2: Testing of polymer-based plain bearing materials(ISO 7148-2:2012),English translation of DIN ISO 7148-2:2014-07Gleitlager Prfung des tribologischen Verhaltens von Gleitlager
3、werkstoffen Teil 2: Prfung von polymeren Gleitlagerwerkstoffen (ISO 7148-2:2012),Englische bersetzung von DIN ISO 7148-2:2014-07Paliers lisses Essai du comportement tribologique des matriaux antifriction Partie 2: Essai des matriaux pour paliers base de polymre (ISO 7148-2:2012),Traduction anglaise
4、de DIN ISO 7148-2:2014-07SupersedesDIN ISO 7148-2:2001-03www.beuth.deDocument comprises 29 pagesIn case of doubt, the German-language original shall be considered authoritative.07.14 A comma is used as the decimal marker. Contents Page National foreword .3 National Annex NA (informative) Bibliograph
5、y 4 1 Scope 5 2 Normative references 5 3 Symbols, units and abbreviated terms 5 4 Special features for the tribological testing of polymer-based materials6 5 Test methods 9 5.1 General 9 5.2 Test method A Pin-on-disc .9 5.3 Test method B Block (or pin)-on-ring .10 5.4 Test method C Plain bearing-on-
6、shaft 11 5.5 Test method D Sphere-on-prism .11 5.6 Test method E Rotation under thrust load .12 6 Test specimens 13 6.1 Data required 13 6.2 Polymer-based plain bearing materials (pl) 13 6.3 Materials of mating component 13 6.4 Dimensions of test specimens .13 6.5 Preparation of the test specimens .
7、18 7 Test methods and test equipment .19 7.1 General 19 7.2 Test method A Pin-on-disc .19 7.3 Test method B Block-on-ring .20 7.4 Test method C Plain bearing-on-shaft 20 7.5 Test method D Sphere-on-prism .20 7.6 Test method E Rotation under thrust load .21 8 Lubrication .21 8.1 General 21 8.2 Dry (d
8、r) 22 8.3 Grease (gr) 22 8.4 Oil (oi) 22 8.5 Solid lubricant (so) 22 9 Designation 22 10 Test conditions 22 10.1 Environmental conditions .22 10.2 Mounting of the test specimens .23 10.3 Test variables .23 11 Test procedure .25 11.1 Running-in 25 11.2 Carrying out the tests 25 12 Analysis 25 12.1 Ge
9、neral 25 12.2 Test results .26 Annex A (informative) Test report .27 Bibliography 29 DIN ISO 7148-2:2014-07 2 DIN ISO 7148-2:2014-07 3 National foreword This document (ISO 7148-2:2012) has been prepared by Technical Committee ISO/TC 123 “Plain bearings” (Secretariat: JISC, Japan), Subcommittee SC 2
10、“Materials and lubricants, their properties, characteristics, test methods and testing conditions”. The responsible German body involved in its preparation was the Normenausschuss Wlz- und Gleitlager (Rolling Bearings and Plain Bearings Standards Committee), Working Committee NA 118-02-02 AA Werk-st
11、offe, Schmierung, Prfung. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. DIN and/or DKE shall not be held responsible for identifying any or all such patent rights. DIN ISO 7148 consists of the following parts, under the general
12、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 The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 527-2 DIN EN ISO 527-2
13、 ISO 527-3 DIN EN ISO 527-3 ISO 2818 DIN EN ISO 2818 ISO 6691 DIN ISO 6691 Amendments This standard differs from DIN ISO 7148-2:2001-03 as follows: a) normative references have been updated; b) new test methods have been included; Previous editions DIN ISO 7148-2: 2001-03 National Annex NA (informat
14、ive) Bibliography DIN EN ISO 527-2, Plastics Determination of tensile properties Part 2: Test conditions for moulding and extrusion plastics DIN EN ISO 527-3, Plastics Determination of tensile properties Part 3: Test conditions for films and sheets DIN EN ISO 2818, Plastics Preparation of test speci
15、mens by machining DIN ISO 6691, Thermoplastic for plain bearings Classification and designation DIN ISO 7148-2:2014-07 4 1 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,
16、 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 polymer material combinations used in plain bearings, reproducible meas
17、ured 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 application only if all parameters of influence are identical. The more the test
18、 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 of this document. For dated references, only the edition cited applies. For undated referenc
19、es, 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 plasticsISO 527-3, Plastics Determination of tensile properties Part 3: Test conditions for films and sheets
20、ISO 2818, Plastics 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.Plain bearings Testing of the tri
21、bological behaviour of bearing materials Part 2: Testing of polymer-based bearing materials DIN ISO 7148-2:2014-07 5 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 f
22、orce, i.e.: fFFfn=-FfFriction force NFnNormal force Ngr Grease KwCoefficient of wear, volumetric 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
23、) N/mm2Rd,BCompression strength N/mm2Rd0,2Compression limit 0,2 % N/mm2so Solid lubricant TSpecimens temperature near the sliding surface during testing under steady-state conditionsCTambAmbient temperature CTgGlass transition temperature CTlimMaximum permissible temperature CtChTest duration hU Sli
24、ding velocity m/sVWMaterial removed by wear as measured by change in volume mm3wlLinear wear rate, 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
25、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 specimens have expanded under fri
26、ctional 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.DIN ISO 7148-2:2014-07 6 Polymers have a glass transition t
27、emperature, Tg, 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 machined surfaces. The test specimens shall be tested with the same surface conditio
28、ns 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 should have the same fibre orientation as in practical application.In order to avoi
29、d 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 remains stationary. The test system shall be similar to practical application.Polymers s
30、how 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 rough. Also ploughing wear and melting or plastic deformation is possible. Therefore,
31、 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 deformed).Some polymers may show poor repeatability of the results and require repeated t
32、esting (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. polyamides, moisture absorption effects a gradual change in linear dimensions and modifie
33、s 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 from the actual application, the greater is the uncertainty of the applicability of the res
34、ults (see Figures 1 and 2).a) Plain bearing-on-shaftDIN ISO 7148-2:2014-07 7 b) Linear guidance systemFigure 1 Simulation of real rubbing contactsa) Pin-on-discb) Block-on-ringc) Sphere-on-prismDIN ISO 7148-2:2014-07 8 d) Rotation under thrust load Sleeve-to-sleevee) Rotation under thrust load Sleev
35、e-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 methods should correspond to
36、 the practical application as closely as possible.5.2 Test method A Pin-on-discSee Figure 3.DIN ISO 7148-2:2014-07 9 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 li
37、near 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.Figure 3 Test method A Pin-on-disc5.3 Test method B Block (or pin)-on-rin
38、gSee 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 injection moulding of the block because of problems with shrinkage and f
39、ibre 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-ringDIN ISO 7148-2:2014-07 10 5.4 Test method C Plain bearing-on-shaftSee Figure 5.Advantages: best simulation of all possible s
40、ystems; testing of original 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
41、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 and without lubrication (test specimen contains reservoir for lubricant); testing of lubricants interaction with
42、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.Disadvantages: plastic deformation might affect results; increasing sliding surface area due to wear under dry conditio
43、ns.Figure 6 Test method D Sphere-on-prismDIN ISO 7148-2:2014-07 11 5.6 Test method E Rotation under thrust loadSee Figure 7.a) E1 Sleeve-to-sleeveb) E2 Sleeve-to-plateFigure 7 Rotation under thrust loadAdvantages: basic testing of simple specimens; injection-moulded test specimens available; testing
44、 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 injection-moulded specimens affects result
45、s.DIN ISO 7148-2:2014-07 12 6 Test specimens6.1 Data requiredFor one series of tests, several specimens of one material shall be from the same batch, with uniform state after conditioning and uniform finish of the sliding surface. Machined and injection-moulded specimens may create different results
46、 because crystallinity can vary with depth from the surface. They should be tested separately.As the structural condition of the mating materials constitutes an essential factor as far as the repeatability of the test results is concerned, the following information is necessary:a) material specifica
47、tion and composition, including fillers or details of fibre reinforcement (as specified in ISO 6691);b) method of manufacture;c) structure, e.g. density, degree of crystallinity;d) mechanical material properties, e.g. Shore hardness, 0,2 % compression limit, Rd0,2(as specified in ISO 4385), compress
48、ion strength, Rd,B;e) state of conditioning, e.g. moisture content;f) surface condition and surface roughness, Ra, e.g. injection-moulded, machined (as specified in ISO 2818), turned, ground, lapped, polished, milled.6.2 Polymer-based plain bearing materials (pl)These may be made by moulding, inject
49、ion moulding or by cutting bar or tube to length or by machining all over from semi-finished materials or by cutting from injection-moulded or laminated (composite) plates.If fibre-reinforced polymers are to be tested, the fibres shall lie in the same direction in the test as in the final product, e.g. parall
