1、Designation:D742010 Designation: D7420 11Standard Test Method forDetermining Tribomechanical Properties of GreaseLubricated Plastic Socket Suspension Joints Using a High-Frequency, Linear-Oscillation (SRV) Test Machine1This standard is issued under the fixed designation D7420; the number immediately
2、 following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis test m
3、ethod was originally published as bilingual company standard TRW 62 051 301 in June2002. TRW Fahrwerksysteme2transferred the copyright on Oct. 5, 2004 to standardization bodies. TheDIN 51834 working group has modified this standard by adding precision information based on roundrobin tests.1. Scope*1
4、.1 This test method covers a procedure for determining the friction and wear behavior of grease lubricated plastic socketsuspension joints, for validation of suspension joint greases and quality inspection for those greases under high-frequencylinear-oscillation motion using the SRV test machine.1.2
5、 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appr
6、opriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3A295 Specification for High-Carbon Anti-Friction Bearing SteelD217 Test Methods for Cone Penetration of Lubricating GreaseD4175 Terminology Relating to
7、 Petroleum, Petroleum Products, and LubricantsD5706 Test Method for Determining Extreme Pressure Properties of Lubricating Greases Using a High-Frequency,Linear-Oscillation (SRV) Test MachineE45 Test Methods for Determining the Inclusion Content of SteelG40 Terminology Relating to Wear and Erosion2.
8、2 DIN Standards:4DIN 51631:1999 Special-boiling-point spirits - Requirements and testingDIN EN 10025-1:2005 Hot rolled products of structural steels - Part 1: General technical delivery conditionsDIN EN ISO 683-17 Heat-treated steels, alloy steels and free-cutting steels - Part 17: Ball and roller b
9、earing steels (replacesDIN 17230-1980)DIN EN ISO 13565-2:1998 Geometrical Product Specifications (GPS) - Surface texture: Profile method - Surfaces havingstratified functional properties - Part 2: Height characterization using the linear material ratio curve2.3 ISO Standard:ISO 1250:1972 Mineral sol
10、vents for paints - White spirits and related hydrocarbon solvents1This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.G0 onLubricating Grease.Current edition approved March 1, 2010. Published April
11、 2010. DOI:10.1520/D742010.Current edition approved Dec. 1, 2011. Published March 2012. Originally approved in 2010. Last previous edition approved in 2010 as D742010. DOI:10.1520/D742011.2TRW Fahrwerksysteme (Chassis Systems), D-50543, Dsseldorf, Germany.3For referencedASTM standards, visit theASTM
12、 website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4Available from Beuth Verlag GmbH (DIN- DIN Deutsches Institut fur Normung e.V.), Burggrafenstrasse 6, 107
13、87, Berlin, Germany, http:/www.en.din.de.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, AS
14、TM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, P
15、O Box C700, West Conshohocken, PA 19428-2959, United States.3. Terminology3.1 Definitions:3.1.1 break-in, nin tribology, an initial transition process occurring in newly established wearing contacts, often accompaniedby transients in coefficient of friction or wear rate, or both, which are uncharact
16、eristic of the given tribological systems long-termbehavior. G40D7420 1123.1.2 coeffcient of friction, or , nin tribology, the dimensionless ratio of the friction force (F) between two bodies to thenormal force (N) pressing these bodies together. G403.1.3 lubricant, nany material interposed between
17、two surfaces that reduces the friction or wear between them. D41753.1.4 lubricating grease, na semifluid to solid product of a dispersion of a thickener in a liquid lubricant. D2173.1.4.1 DiscussionThe dispersion of the thickener forms a two-phase system and immobilizes the liquid lubricant by surfa
18、cetension and other physical forces. Other ingredients are commonly included to impart special properties.3.1.5 nitro-carburizationnitro-carburization, nnitro-carburizing is not defined in the ASTM Dictionary of EngineeringScience and Technology, but is defined in DIN EN 10025-1:2005.3.1.6 Ra (C.L.A
19、.), nin measuring surface finish, the arithmetic average of the absolute distances of all profile points from themean line for a given distance. Amstutz53.1.7 Rpk, nReduced peak height according to DIN EN ISO 13565-2:1998. Rpk is the mean height of the peak sticking outabove the core profile section
20、.3.1.8 Rvk, nReduced valley height according to DIN EN ISO 13565-2:1998. Rvk is the mean depth of the valley reachinginto the material below the core profile section.3.1.9 Rz (DIN), nin measuring surface finish, the average of all Ry values (peak to valley heights) in the assessment length.Amstutz63
21、.1.10 thickener, nin lubricating grease, a substance composed of finely divided particles dispersed in a liquid lubricant toform the products structure. D2173.1.10.1 DiscussionThe thickener can be fibers (such as various metallic soaps) or plates or spheres (such as certain non-soapthickeners) which
22、 are insoluble or, at most, only very slightly soluble in the liquid lubricant. The general requirements are that thesolid particles be extremely small, uniformly dispersed, and capable of forming a relatively stable, gel-like structure with the liquidlubricant.3.2 Definitions of Terms Specific to T
23、his Standard:3.2.1 metal specimen, nrepresented by the lower specimen. Ball stud or ball pins are also used as common synonym.3.2.2 plastic socket, nrepresented by the upper polymeric disk specimen. Plastic seat or beating is also used as commonsynonym.3.2.3 seizure, nlocalized adhesionfusion of pol
24、ymer onto metal between the rubbing surfaces of the test pieces. D57063.2.3.1 DiscussionIn this test method, seizure is indicated by a sharp rise in the coefficient of friction, over steady state, ofgreater than 0.2 for over 20 s. In severe cases, a stoppage in the motor will occur (for example, see
25、 Test Method D5706).3.2.43.3 Abbreviations:3.3.1 SRV, nSchwingung, Reibung, Verschlei (German); oscillating, friction, wear (English translation).4. Summary of Test Method4.1 This test method is performed on SRV test machine using a polymeric disk having three flat pins oscillating at 50 Hz againsta
26、 steel test disk with lubricant (grease) between them. Test load is fixed to 2000 N using a test temperature of 50C and a strokeof 1.5 mm during a test time of 2 h.NOTE 1Test frequency, stroke length, temperature, and polymeric disk and disk material can be varied to simulate field conditions. The p
27、olymericdisk having three flat pins yields surface-on-flat contact geometry.NOTE 2This test can not be executed with SRV I and SRV II models, as they are limited to 1200 N and 1400 N, respectively. The SRV III and SRVIV model are from the test chamber and operating conditions identical, but the SRV
28、IV model allows to tilt and rotate the test chamber. Both are fullycomputer controlled. This test runs in the SRV IV models horizontally and untilted.5. Significance and Use5.1 This test method can be used to quickly determine the lubricating ability of greases lubricating automotive plastic sockets
29、uspension joints. This test method has found wide application in qualifying greases used in chassis systems. This test method isa material and application oriented approach based on inputs from field experiences for characterizing the tribological behavior(friction and wear) using random, discrete,
30、and constant parameter combinations. Users of this test method should determinewhether results correlate with field performance or other applications prior to commercialization.6. Apparatus6.1 SRV Test Machine,7See Fig. 1 and Fig. 2.7. Reagents and Materials7.1 Polymeric Test Disk with Three Pins, =
31、 18.2+0.2-mm diameter. Each pin has a diameter of = 3.0-mm (see Fig. X1.1).5Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.5Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-T
32、P-003-0785, Sheffield Measurement Division, Warner and Swasey, 1985, p. 216Amstutz, Hu, “Surface Texture: The Parameters,”, Bulletin MI-TP-003-0785, Sheffield Measurement Division, Warner and Swasey, 1985, pp. 2931.7Amstutz, Hu, “Surface Texture: The Parameters”, Bulletin MI-TP-003-0785, Sheffield M
33、easurement Division, Warner and Swasey, 1985, pp. 2931.D7420 113The plastic specimen should represent characteristic items of an inner plastic socket surface. Specimens are molded from originalsocket material; functional surfaces shall be free from scratches and any surface damages.7.2 Lower Test Di
34、sk7Vacuum arc remelted (VAR) AISI 52100 steel with a inclusion rating using Method D, Type A, asseverity level number of 0.5 according to Test Methods E45 and Specification A295 or a inclusion sum value K1 # 10 accordingto DIN EN ISO 683-17 and spherodized annealed to obtain globular carbide, 62 6 1
35、 HRC hardness, the surfaces of the disk beinglapped and free of lapping raw materials. The topography of the disk will be determined by four values:7The sole source of supply of the apparatus known to the committee at this time is Optimol Instruments GmbH, Westendstr. 125, D-80339 Munich, Germany. I
36、f you areaware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend.NOTEAbove: Model III; Below: Model IVFIG. 1 SRV Test MachineD7420 114
37、0.5 m Rz 0.650 m0.35 m C.L.A. (Ra) 0.050 m0.020 m Rpk 0.035 m0.050 m Rvk 0.075 m (24 6 0.5mm diameter by 7.8 6 0.1mm thick)If other surface roughnesses are applied, they have to be measured and stated in the report. The type of coating and/orthermomechanical treatment has to be reported.NOTE 3The st
38、eel 41CrS4 (DIN 1.7039) is also used in practice. The test disks should be polished to RZ1-1.5 m and can be carbo-nitrided.7.3 Grease, Store in a sealed container prior to testing. (Different greases have different characteristics for storage stability andshelf life and users should be guided by the
39、ir own knowledge of the material to be tested, or by the recommendation of thesupplier.)7.4 Cleaning Solvent, Special boiling point spirit type 2-Ain accordance with DIN 51631or ISO 1250. (WarningFlammable.Health hazard.)8. Preparation of Apparatus8.1 SRV Machine Generation III and IVTurn on the tes
40、t machine and the computer, and allow them to warm up for 15 minprior to running tests.9. Procedure9.1 Check the polymeric disk for visible damage or scratches. Clean the polymeric disk and the steel disk by wiping the surfaceswith laboratory tissue soaked with the cleaning solvent. Repeat wiping un
41、til no dark residue appears on the tissue. Immerse thesteel disk in a beaker of the cleaning solvent under ultrasonic vibration for 10 min. Dry the steel test disk with a clean tissue toensure no streaking occurs on the surface. Generally, a new specimen should be used for each test.NOTE 4Ensure tha
42、t the polymer and the constituents of the blend is resistant to the solvent. If the binder is not resistant to the solvent, wipe onlythe polymeric disk surface with a laboratory tissue.9.2 Prior to testing, determine thickness of plastic specimen in all three contact surfaces (pins) by a micrometer
43、gauge caliperrule. Document measurement readings in the test report.9.3 Place the grease using a calibration ring while ensuring that the grease is applied to a height of 0.2-0.3 mm above the metaltest disk.9.4 Place the cleaned polymeric test disk in the adapter with the level side facing the adapt
44、er and the test surface with the threepins pointing upwards. Align the polymeric test disk as shown in Fig. 3.9.5 Tighten the test disk by means of the three screws at the side of the adapter. Place the adapter holding the polymeric testdisk on the lower disk so that the three pins are immersed in t
45、he grease.1. Oscillation drive rod 6. Electrical Resistance Heater2. Test Ball Holder 7. Resistance Thermometer3. Load Rod 8. Test Disk Holder4. Test Ball 9. Piezoelectric Measuring Device5. Test Disk 10. Receiving BlockFIG. 2 Test Chamber Elements (Schematic) of SRV Test MachineD7420 1159.6 Place a
46、 10-mm steel ball in the ring/area specimen holder and tighten it.9.7 Place a small quantity of lubricant in the recess of the adapter.9.8 Place the specimen holder containing the ball into the recess of the adapter.9.9 Position the specimen combination comprising the ring/area holder and ball, the
47、adapter with the polymeric disk and thelower test disk on the test platform in the test chamber. Make sure that one pin of the polymeric test disk is pointing towards theoperator.9.10 Insert the ring-area specimen holder in the openings of the drive axles and tighten it with knurled screws. Slightly
48、 tightenthe lower test disk by means of a clamping bow.9.11 In the SRV basic software, enter the following test parameters:Frequency = 50 HzStroke = 1.5 mmTemperature = 50CLoad 50 N for 30 s, then increase load to 2000 NTest duration = 120 min9.12 To fully tighten the specimen combination, follow th
49、e instructions of the SRV software.10. Report10.1 During testing, friction coefficient f determined from test load Fnand friction load Ffis recorded as well as actual testingtemperature. Friction coefficient traces must be stored on data records.FIG. 3 Test Geometry and Orientation of the Upper Polymeric PinSpecimen in Respect to Oscillatory MotionD7420 11610.2 Report the following informationall parameters used to evaluate material:10.2.1 Temperature, C,10.2.2 Stroke, mm,10.2.3 Frequency, Hz,10.2.4 Relative humid
