1、July 2014 Translation by DIN-Sprachendienst.English price group 9No 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!%7H2“2203715www.din.deDDIN ISO 7148-1Plain bearings Testing of the tribological behaviour of bearing materials Part 1: Testing of bearing metals (ISO 7148-1:2012),English translation of DIN ISO 7148-1:2014-07Gleitlager Prfung des tribologischen Verhaltens von Gleitlagerwerkstoffen Teil 1: Pr
3、fung von Lagermetallen (ISO 7148-1:2012),Englische bersetzung von DIN ISO 7148-1:2014-07Paliers lisses Essai du comportement tribologique des matriaux antifriction Partie 1: Essai des matriaux mtalliques (ISO 7148-1:2012),Traduction anglaise de DIN ISO 7148-1:2014-07SupersedesDIN ISO 7148-1:2001-03w
4、ww.beuth.deDocument comprises 14 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 1 Scope 4 2 Normative references 4 3 Symbols and units .4 4 Special features for the tribological tes
5、ting of metallic bearing materials 5 5 Test methods 5 5.1 Test method A Pin-on-disc .5 5.2 Test method B Block-on-ring .6 5.3 Test method C Rotation under thrust load .7 6 Test specimens 8 6.1 Disc .8 6.2 Ring .8 6.3 Pin .8 6.4 Block .8 6.5 Sleeve 8 6.6 Plate 9 6.7 Preparation of the test specimens
6、.9 7 Test methods and test equipment .10 8 Lubrication .10 9 Designation 10 10 Test conditions 10 11 Test procedure .11 Annex A (informative) Test report .12 Bibliography 14 DIN ISO 7148-1:2014-07 2 DIN ISO 7148-1:2014-07 3 National foreword This document (ISO 7148-1:2012) has been prepared by Techn
7、ical Committee ISO/TC 123 “Plain bearings” (Secretariat: JISC, Japan), Subcommittee SC 2 “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 Be
8、arings and Plain Bearings Standards Committee), Working Committee NA 118-02-02 AA Werk-stoffe, 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
9、 all such patent rights. DIN 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 Amendments This standard differs from DIN ISO
10、 7148-1:2001-03 as follows: a) normative references have been updated; b) a new test method has been included. Previous editions DIN ISO 7148-1: 1987-10, 2001-03 1 ScopeThis part of ISO 7148 specifies tribological tests of metallic bearing materials for plain bearings under conditions of boundary lu
11、brication.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 material for running repeatedly or for long periods u
12、nder 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 for practical application only if all parameters of
13、 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 of this document. For dated references, only the
14、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 and unitsSymbol Term UnitA, B, C Test method a Slid
15、ing 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) DIN ISO 7148-1:2014-07 4 Plain bearings Testing of the tribological behaviou
16、r of bearing materials Part 1: Testing of bearing metals 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 l
17、imit 0,2 % N/mm2RmTensile 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
18、 in volume mm3wlLinear 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
19、 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 bearing are always fully separated by a film of lubricant. Under such conditions, friction depends on the rheological
20、 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 likely. This may be during the starting or running down phase of a hydrodynamic plain bearing or when high loads, l
21、ow sliding velocities, 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)DIN ISO 7148-1:2014-07 5 Key1 disc or ring2 pin or blockFigure 1 Pin-on-disc test m
22、ethod5.2 Test method B Block-on-ringFigure 2 shows a schematic drawing of a block and ring assembly.DIN ISO 7148-1:2014-07 6 Key1 disc or ring2 pin or blockFigure 2 Block-on-ring test method5.3 Test method C Rotation under thrust loadFigure 3 shows schematic drawings of a sleeve-to-sleeve and sleeve
23、-to-plate assembly.a) C1 Sleeve-to-sleeveDIN ISO 7148-1:2014-07 7 b) C2 Sleeve-to-plateFigure 3 Rotation under thrust load6 Test specimens6.1 DiscThe disc shall have the following preferred dimensions: diameter, d1: 40 mm to 110 mm; width b: 8 mm to 12 mm.The diameter of the sliding track shall be n
24、oted 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 preferably 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
25、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.DIN ISO 7148-1:2014-07 8 Dimensions in millimetresFigure 4 Dimensions of sleeve6.6 PlateThe plate can be made by machining. The preferred basic dimensions of
26、the sleeve are shown in Figure 5.Dimensions in millimetresFigure 5 Dimensions of plate6.7 Preparation of the test specimensAfter preparing the test surfaces with the same machining methods in order to obtain a suitable surface finish (similar to the application which is to be simulated), the specime
27、ns 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.DIN ISO 7148-1:2014-07 9 7 Test methods and test equipmentThe pin, block, sleeve or plate, made of the bearing ma
28、terials, is pressed with a known normal force, Fn, against the rotating specimen (disc, ring or sleeve) made from 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
29、 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 exceed the thickness of the surface bearing material layer. For thin layers, test met
30、hod 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.Equipment for the continuous measurement of friction and wear shall be available.
31、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 applied normal force, shall be avoided.8 LubricationOil or grease lubrication shall b
32、e 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 preferable for the specimens to be completely immersed in the oil. Spray lubrication m
33、ay 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 results can vary widely depending on the lubricant used.9 DesignationEXAMPLE The testing
34、of the tribological behaviour of metallic bearing materials according to test method A (pin-on-disc) is designated 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 plat
35、e (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 specimens; normal force, Fn; lubricant temperature, TL; sliding distance, a; sliding velocity
36、, U;DIN ISO 7148-1:2014-07 10 overlap ratio, KA.In order to simulate 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
37、, it is important that the surfaces be typical for that application, 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 t
38、o 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 boundary lubrication for appreciable periods of time, this can be taken into account by performing a long-term test, measuring the wear volume
39、 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 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
40、 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 practical application.When comparing material/lubricant combinations in which the bearing materials have different mechanical properties and load capa
41、cities, the test may be carried out with values of normal force which 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 o
42、f 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 TL, a temperature corresponding to the highest temperature which is expected to o
43、ccur 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 combinations without reference to a specific applicatio
44、n, the normal force, Fn, and the lubricant temperature TL(and possibly the surface roughness values Ra) should be varied, preferably, between wide limits.11 Test procedureFriction sliding distance and wear sliding distance curves shall be recorded so that, among others, the periods of running in and
45、 steady-state can be distinguished. The total sliding distance shall be presented in the results.After the tests have been completed, wear of the mating material surface shall also be measured, e.g. by profile tracing with a stylus instrument, so that the contribution of the wear of the mating mater
46、ial to the total wear may be evaluated. This also reveals whether or not the mating material surface has been scratched by contact with the bearing material. In addition, wear of the bearing material shall be determined by weighing before and after the test (after removal of all loose debris). The t
47、est parameters shall be chosen so that the mass of the bearing material removed by wear is more than 5 mg.After the test has been completed, inspect the surface conditions of both the sliding surfaces (formation of a reaction layer, transferred material, scratches, etc.).NOTE Tribological test resul
48、ts can vary considerably from one test to another.To obtain results that are as reliable as possible, it is necessary to run several tests of each combination.DIN ISO 7148-1:2014-07 11 Annex A (informative) Test reportUnless otherwise agreed, the test report shall include the following information:T
49、able A.1 Test reportTest ISO 71481 Symbol UnitPin, block, sleeve or plateDisc, ring or sleeveSpecimens:Type/name Chemical composition Method of production Heat treatment Micro structure Mechanical properties:Hardness HB, HV, HRC Tensile strength RmN/mm20,2 % Proof stress Rp0,2N/mm2Elongation at fracture A5% Dimensions mm Diameter of sliding track mm Surface treatment Surface finishing method Surface roughness Ra m
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1