ASTM D6425–99 英文版

Designation: D 6425 – 9902 An American National Standard Standard Test Method for Measuring Friction and Wear Properties of Extreme Pressure (EP) Lubricating Oils Using SRV Test Machine1 This standard is issued under the fixed designation D 6425; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. INTRODUCTION This test method represents the transformation of DIN 51834-2:1997. The DIN working group implemented changes at its annual meeting in Munich in September 2000. ASTM Committee D02 adopted these modifications as closely as possible. The DIN working group widens the scope of the standard to accommodate different test conditions and refines repeatability and reproducibility on the base of four international RR tests. It also introduces the wear volume as a tribological quantity. 1. Scope 1.1 This test method covers an extreme pressure (EP) lubricating oil’s coefficient of friction and its ability to protect against wear when subjected to high-frequency, linear oscillation motion. The procedure is identical to that described in DIN 51834. 1.2 This test method can also be used to determine the ability of a non-EP lubricating oil to protect against wear and its coefficient of friction under similar test conditions. 1.3 The values stated in SI units are to be regarded as the standard. The values given in the parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: D 4175 Terminology Relating to Petroleum, Petroleum Products, and Lubricants2 1 This test method is under the jurisdiction of ASTM Committee D-2 D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.L0.11 on Tribiological Properties of Industrial Fluid Lubricants. Current edition approved June Dec. 10, 1999. 2002. Published August March 2003. Originally approved in 1999. Last previous edition approved in 1999 as D 6425–99. 1 This 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. Because it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version of the standard as published by ASTM is to be considered the official document. Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. G 40 Terminology Relating to Wear and Erosion3 2.2 OtherDIN Standards:4 DIN 17230 Roller Bearing Steels DIN 51631:1999 Mineral spirits; special boiling point spirits; requirements DIN 51834, Tribiological Test in the Translatory Oscillation Apparatus (Part 2: Determination of Friction and Wear Data for Lubricating Oils) DIN EN ISO 13565-2:1998 Geometrical Product Specifications (GPS)—Surface Texture: Profile Method; Surfaces having Stratified Functional Properties—Part 2: Height Characterization using Linear Material Ratio Curve (replacement of DIN 4776:1990) 2.3 ISO Standards:5 ISO 1250:1972 Mineral Solvents for Paints, White Spirits and Related Hydrocarbon Solvents 3. Terminology 3.1 Definitions: 3.1.1 break-in, n—in tribiology , an initial transition process occurring in newly established wearing contacts, often accompanied by transients in coefficient of friction or wear rate, or both, that are uncharacteristic of the given tribiological system’s long term behavior. (Synonym: run-in, wear-in) G 40 3.1.2 C.L.A., n—in measuring surface finish, the arithmetic average of the absolute distances of all profile points from the mean line for a given distance.6 3.1.3 coeffıcient of friction µ or f, n—in tribiology, the dimensionless ratio of the friction force (Ff) between two bodies to the normal force (Fn) pressing these bodies together. G 40 µ 5 ~Ff / Fn! (1) 3.1.34 EP lubricating oil, n—a liquid lubricant containing an extreme pressure (EP) additive 3.1.45 extreme pressure (EP) additive, n—in a lubricant, a substance that minimizes damage to metal surfaces in contact under high stress rubbing conditions. D 4175 3.1.56 Hertzian contact area, n—the apparent area of contact between two nonconforming solid bodies pressed against each other, as calculated from Hertz’ equations of elastic deformation. G 40 3.1.67 Hertzian contact pressure, n—the magnitude of the pressure at any specified location in a Hertzian contact area, as calculated from Hertz’ equations of elastic deformation. G 40 3.1.78 lubricant, n—any substance interposed between two surfaces for the purpose of reducing the friction or wear between them. G 40 3.1.8 wear, n—damage to a solid surface, generally involving progressive loss of material, due to relative motion between that surface and a contacting substance or substances. G 40 3.1.9 C.L.A.Pgeom., n—in measuring surface finish,—geometric contact pressure describes the arithmetic average of the absolute distances of all profile points from the mean line for a given distance.5 load carrying capacity at test end. 2 Annual Book of ASTM Standards, Vol 05.02. 3 Annual Book of ASTM Standards, Vol 03.02. 4 Available from Deutsches Institut für Normunge, Beuth Verlag GmbH, Burggrafenstrasse 6, D-10787 Berlin, Germany. 5 Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-TP-003-0785, Sheffield Measurement Division, Warner and Swazey, 1985, p. 21. 5 Available from International Organization for Standardization (ISO), 1 rue de Varembé, Case postale 56, CH-1211, Geneva 20, Switzerland. 6 ASM Handbook, “Friction, Lubrication, 6 Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-TP-003-0785, Sheffield Measurement Division, Warner and Wear Technology,” Vol 18, October 1992. Swazey, 1985, p. 21. D 6425 – 9902 2 3.1.10 RpK, n—Reduced peak height according to DIN EN ISO 13565-2:1998. RpK is the mean height of the peak sticking out above the core profile section. 3.1.11 RvK, n—Reduced valley height occording to DIN EN ISO 13565-2:1998. RvK is the mean depth of the valley reaching into the material below the core profile section. 3.1.12 Ry, n—in measuring surface finish, the vertical distance between the top of the highest peak and the bottom of the deepest valley in one sampling length of the roughness profile.6 3.1.13 Rz, n—in measuring surface finish, the average of all Ry values (peak to valley heights) in the assessment length. 3.1.11 Ry6 3.1.14 wear, n—in measuring surface finish, the vertical distance between the top—damage to a solid surface, generally involving progressive loss of the highest peak material, due to relative motion between that surface and a contacting substance or substances. G 40 3.1.15 Wv, n—Wear volume is the bottom loss of volume to the deepest valley in one sampling length of the roughness profile.5 ball after a test. 3.2 Definitions of Terms Specific to This Standard: 3.2.1 seizure, n—thestopping of the relative motion as the result of interfacial friction. Discussion: the seizure criteria are the stoppage of the machine, a sharp increase of the coefficient of friction of >+0.2 for over 20 seconds or a coefficient of friction >0.35. If any of these conditions occur the test is not valid. (These criteria were believed to be right, because this standard is related to liquid lubricants). 7 4. Summary of Test Method 4.1 This test method is performed on an SRV test machine using a test ball oscillated at constant frequency and stroke amplitude and under constant load (Fn), against a test disk that has been moistened with the lubricant specimen. The platform to which the test disk is attached is held at a constant temperature. NOTE 1—The frequency of oscillation, stroke length, test temperature, test load, test duration, and test ball and disk material can be varied from those specified in this test method. The test ball yields Hertzian point contact geometry. To obtain line or area contact, test pieces of differing configurations can be substituted for the test ball. 4.2 The friction force, Ff, is measured by a piezo-electric device in the test disk assembly. Peak values of coefficient of friction, f, are determined and recorded as a function of time. 4.3 After a pre-set test period, the test machine and chart recorder are stopped and the wear scar on the ball is measured. If a profilometer is available, a trace of the wear scar on the test disk can also be used to obtain additional wear information. 5. Significance and Use 5.1 This test method can be used to determine anti-wear properties and coefficient of friction of EP lubricating oils at selected temperatures and loads specified for use in applications in which high-speed vibrational or start-stop motions are present for extended periods of time under initial high Hertzian point contact pressures. It has found application as a screening test for lubricants used in gear or cam/follower systems. Users of this test method should determine whether results correlate with field performance or other applications. 6. Apparatus 6.1 SRV Test Machine8 (see Fig. 1), consists of an oscillation drive, a test chamber (see Fig. 2), and a loading device9 with a servomotor and a load cell. The machine is operated by a control device for the oscillating drive, a timer, a load control, a frequency control, a stroke control, a data amplifier to determine the friction coefficient, and a switch and a controller for the heating. An oscilloscope may be used for monitoring. Friction coefficients are recorded in relation to time by a chart recorder, or by data acquisition in a computer. 6.1.1 On the firmly mounted receiving block (1) in the test chamber (see Fig. 3), there is a piezoelectric device (2) to measure the friction force, Ff, and the friction coefficient, f; the holder for the test disk (3) with a thermostat-controlled electrical resistance heating element (4); a resistance thermometer (5); the oscillation drive rods (6); an exchangeable holder for the test ball (7); and the load rods of the loading device (8). 6.1.2 The design of the receiving block for the test disk should be such that it has integrated cooling coils, or that cooling coils are wound round it, so that the receiving block must be capable to maintaining test temperatures below ambient are possible. down 7 The sole source of supply known to the committee at this time is Optimol Instruments Prüftechnik GmbH, Friedenstrasse 10, D 81671 Munich, Germany. If you are aware of alternative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee,1 which you may attend. 7 ASM Handbook, “Friction, Lubrication, and Wear Technology,” Vol 18, October 1992. 8 Supporting data have been filed 8 The sole source of supply known to the committee at this time is Optimol Instruments Prüftechnik GmbH, Friedenstrasse 10, D 81671 Munich, Germany. If you are aware of alternative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee,1 which you may be obtained by requesting Research Report RR:D02-6425. attend. 9 Optimol Instruments supplies an up-grade kit to allow older machines to operate with 1,600 N, if needed. D 6425 – 9902 3 to +233K. The test disk (9) and the test ball (10) are inserted into their respective holders (3, 4) (see Fig. 3). 6.1.3 Disks are generally used as the lower test piece. Balls, cylinders, rings, or specialized shapes may be used, with appropriate holders, as the upper test piece (see Fig. 4). 6.2 Microscope, equipped with a filar eyepiece graduated in 0.0105-mm divisions or equipped with a micrometre stage readable to 0.0105 mm. Magnification should be sufficient to allow for ease of measurement. One to 103 magnification has been found acceptable. measurement. 6.3 Syringe, suitable for applying 0.03 mL of the lubricating oil under test. 6.4 Tweezers, straight, round, about 200-mm long, with non-marring tips. 6.5 Torque Wrench, initial torque 0.5 to 5 nm. Nm. 6.6 Ultrasonic Cleaner. FIG. 1 SRV Test Machine FIG. 2 Test Chamber 1. Receiving Block 6. O 2. Piezoelectric Measuring Device 7. T 3. Test Disk Holder 8. L 4. Electrical Resistance Heater 9. T 5. Resistance Thermometer 10. FIG. 3 Test Chamber Elements D 6425 – 9902 4 7. Reagents and Materials 7.1 Test Balls,7 AISI 52100 Steel, 60 6 2 HRC hardness, 0.025 6 0.005-µm C.L.A. surface finish, 10-mm diameter. 7.2 Test Disk,7 AISI 52100 steel, 62 6 1 HRC hardness, 0.45 to 0.65-µm Rz the surfaces of the disk are lapped and free of lapping raw materialsu. The topography of the disk will be determined by four vaclues: 0.5 µm < Rz < 0.650 µm; 0.035µm < C.L.A.< 0.050 µm, 0.020 µm < Rpk < 0.035 µm and 0.050 µm < Rvk < 0.075 µm, 24 6 0.5-mm diameter by 7.8 6 0.1-mm thick. NOTE 2—Test pieces made to 100 Cr 6 roller bearing steel (see DIN 17230) are equivalent. 7.3 n-Heptane, reagent grade. NOTE 3—Warning: Flammable. Health Hazard. 7.4 Isopropanol, reagent grade. NOTE 4—Warning: Flammable. Health Hazard. 7.5 Toluene, reagent grade. NOTE 5—Warning: Flammable. Health Hazard. 7.6 Cleaning Solvent, a mixture of equal volumes of n-heptane, isopropanol, and toluene. NOTE 6—Warning: single boiling point spirit type 2-A according to DIN 51631 or ISO 1250. (Warning—Flammable. Health H hazard.) 8. Preparation of Apparatus 8.1 Turn on the test machine and chart recorder and allow to warm up for 15 min prior to running tests. 8.2 Select the friction data to be presented in the crest peak value position in accordance with the manufacturer’s directions. NOTE 73—In most cases, this is accomplished by positioning the sliding switch on electronic card No. 291.35.20E (front side of electronics behind front panel) and the sliding switch located on the back panel of the control unit. 8.3 Turn the amplitude knob to ZERO. 8.4 Switch the stroke adjustment to AUTO position. 8.5 Set the frequency to 50 Hz and duration to 2 h, 00 min, 30 s in accordance with the manufacturer’s instructions. 8.6 Set the load charge amplifier to the setting that corresponds to 300 N the load foreseen for the test in accordance with the manufacturer’s instructions. The test can be run at constant normal forces selected in +100 N increments starting at +100 N. NOTE 84—In later SRV models, the load charge amplifier is set automatically. 8.7 Set the desired span, and calibrate the chart recorder in accordance with the manufacturer’s instructions. Select the desired chart speed. FIG. 4 Test Pieces and Holders for Standard Tribological Contacts D 6425 – 9902 5 9. Procedure 9.1 Installation of the Test Pieces and Lubricating Oil Specimen in the Test Chamber: 9.1.1 Using solvent resistant gloves, clean the test ball, ball holder, and disk by wiping the surfaces with laboratory tissue soaked with cleaning solvent (a mixture of equal volumes of n-heptane, isopropanol, and toluene. (single boiling point spirit type 2-A according to DIN 51631). (Warning—This mixture is flammable and a health hazard.) Repeat wiping until no dark residue appears on the tissue. Immerse the ball and disk in a beaker of the cleaning solvent under ultrasonic vibration (if available) for 10 min. Dry the ball holder. Dry the test ball and disk with a clean tissue, ensuring that no streaking occurs on the surface. 9.1.2 Ensure that the machine is unloaded (indicated by a load reading of –13 or –14 N), and install the ball holder (upper specimen holder). 9.1.3 Place 0.03 mL of the lubricating oil to be tested on the cleaned disk. Then install the disk (place on the block). Tighten the fastening screw until resistance just begins. 9.1.4 Place the cleaned ball, using the tweezers, in the disassembled, cleaned, and dried ball holder. Tighten the fastening screw until resistance just begins. 9.1.5 Install the ball holder, and test ball in the test chamber. 9.1.6 Turn on the heater control, and preheat the disk holder to 50°C. 9.1.7 Apply a load of 50 N, loosen the fastening screws on both disk and ball holders, and then immediately tighten them with a torque wrench to 2.2 to 2.5 nm. Nm. 9.2 Test Run: 9.2.1 Start of the Test Run: 9.2.1.1 Allow 10 min for the test pieces and reference test oil to reach and stabilize at the test temperature. The test can be run at cofnstant temperatures selected in +10 K (+10°C) increments starting at +233K to +553K (-40°C to +280°C). 9.2.1.2 When the temperature has stabilized, turn on the chart recorder paper feed (or the computer) and lower the recording pens. Depress the drive start toggle switch until the timer begins to count and then adjust the stroke amplitude knob to 1.00 mm. NOTE 5—Stroke should be checked periodically by measuring the wear track length minus the ball scar diameter. The difference must be smaller than 610% of the set stroke. 9.2.1.3 When the digital timer reaches 30 s, increase the load to 300 N and run at that load for 2 h 6 15 s. 9.2.2 Terminating the Test Run: 9.2.2.1 The test is automatically terminated by the timer when the preset test time has elapsed. The machine will automatically stop. NOTE 96—Power automatically turns off at the end of the test. NOTE 10—If, 7—If, due to seizure, the friction coefficient exceeds the limit f = 0.35, the test should be terminated. If the machine does not automatically shut down at this point, it may have to be switched off manually. 9.2.2.2 At the end of the test, turn off the heater control, turn power back on, and reduce the load to –13 or –14 N for disassembly. 9.2.2.3 Remove and clean the test ball and disk in accordance with 9.1.1. 9.3 Evaluation: 9.3.1 Place the cleaned test ball on a suitable holder, and using a microscope, measure to the nearest 0.01 mm the scar width in the direction of sliding (d1) and again at 90° to the direction of sliding (d2). The mean wear scar diameter (WSD or Wk) is the average of these two measurements (WSD = (d1 + d2)/2). If the wear scar diameter is smaller than 1.1 times the Hertzian contact diameter, the profile of the wear scar in the center should be measured in order to calculate the wear volume, Wv. If the wear scar diameter is greater than 1.1 times the Hertzian contact diameter, the wear scar diameter should only be reported (see Fig. 5). The wear volume, Wv (mm3), should be used. NOTE 8—It is preferrable to measure wear volume. A procedure for measuring the wear profile and calculating the wear volume is described in DIN 51834:2000, part 3. An official English translation of this procedure is in preparation by DIN.4 9.3.2 Although not specifically part of the procedure, when additional wear analysis is required, perform a profilometric trace across the wear scar on the test disk in accordance with the profilometer manufacturer’s instructions. 9.3.3 Measure the minimum and maximum coefficients of friction (fmin, fmax) and the coefficients at 15, 30, 90, and 120 min (f15 , f30, f 90, f120) from the chart recorder graph or computer, with a precision of 0.001. 9.3.4 If strong fluctuations (band width $ 0.005) in the coefficient of friction are indicated on the chart recorder or other output device adjacent to the point at which the coefficient is measured, record the mean value and the magnitude of the fluctuations at that point (see Fig. 5). 9.3.5 The load carrying capacity can be additionally reported as geometric contact pressure Pgeo