NB/SH/T 0847-2010 Determination of friction and wear properties of extreme pressure lubricating oils SRV testing machine method

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Card type: Test method

1. Method number / full name / English name / replacement relationship

• Standard number: NB/SH/T 0847—2010
• Chinese name: Determination of friction and wear properties of extreme pressure lubricating oils SRV testing machine method
• English name: Standard test method for measuring friction and wear properties of extreme pressure (EP) lubricating oils using SRV test machine
• Replacement relationship: not provided in the available source (no mention of replacing any standard)
• Adoption relationship: modified adoption of ASTM D6425-05 "Determination method for friction and wear properties of extreme pressure lubricating oils (SRV testing machine method)", redrafted according to ASTM D6425-05
• Publication/implementation: published on 2011-01-09, implemented on 2011-05-01
• Publishing unit: National Energy Administration
• Custodianship: National Technical Committee for Standardization of Petroleum Products and Lubricants, Subcommittee on Petroleum Fuels and Lubricants (SAC/TC280/SC1)
• Drafting units: Lubricant Research and Development (Shanghai) Center of China Petroleum & Chemical Corporation, Research Institute of Petroleum Processing of China Petroleum & Chemical Corporation
• Participating drafting unit: Lubricant Tianjin Branch of China Petroleum & Chemical Corporation
• Main drafters: Pu Shangbin, Song Haiqing, Yu Qiaozhen, Lüqiu Qiming, Wang Shuqing
• Main technical differences from ASTM D6425-05:
  • Changed some referenced standards in Chapter 2 of ASTM D6425-05, and referenced standards in Clause 3.1.10 and Clause 3.1.11, to the corresponding national standards of our country
  • Changed the cleaning solvent in Clause 7.3 of ASTM D6425-05 to No. 3 solvent naphtha meeting the requirements of GB 1922
• Editorial modifications:
  • Changed the fixture numbers of the 6.1.2 test ball and test disk in this standard to be consistent with the labels in Figure 3 of ASTM D6425-05
  • Deleted the content of Clause 11.1 in ASTM D6425-05
• Appendix: Appendix A is an informative appendix

2. Scope of application and non-applicability

• 1.1 This standard specifies a test method for determining the friction coefficient and anti-wear performance of extreme pressure lubricating oils using a SRV testing machine under high-frequency linear vibration conditions.
• 1.2 This standard also applies to determining the friction coefficient and anti-wear performance of non-extreme pressure lubricating oils under similar test conditions.
• 1.3 This standard uses International System of Units [SI] units.
• 1.4 This standard involves certain hazardous materials, operations, and equipment, but it is not intended to address all safety issues associated with them. Therefore, users should establish appropriate safety and protective measures before applying this standard, and determine the applicability of relevant regulatory limitations.
• Non-applicability: no explicitly listed non-applicable clauses are provided in the available source.

3. Method principle

• 4.1 On a SRV testing machine, the test ball reciprocates on a test disk dipped in lubricant; the motion frequency, stroke, and applied load (F.) are constant, and the worktable working with the test disk is maintained at a constant temperature.
  • Note: The reciprocating motion frequency, stroke, test temperature, test load, test time, and the materials of the test ball and test disk may differ from the requirements of this standard. The test ball usually produces a Hertzian point contact geometry. To obtain line or area contact, specimens of different shapes may be used instead of the test ball.
• 4.2 The friction force F. is measured by a piezoelectric sensor on the test disk assembly, and the friction coefficient f over the entire test process is measured and recorded.
• 4.3 After the test is completed, the wear scar on the test ball is measured. If a surface profilometer is available, additional wear information can also be obtained from the wear scar on the test disk.

4. Reagents and materials (purity / preparation)

• 7.1 Test ball: AISI 52100 steel, Rockwell hardness HRC is 60±2 (original text "60 2", requires confirmation against the source standard (source-text extraction)), surface roughness requirement is 0.020 μm < C.L.A. < 0.030 μm, diameter is 10 mm.
• 7.2 Test disk: the material is AISI 52100 steel produced by vacuum arc remelting, rated as type A according to inclusion rating method D, and evaluated as stiffness grade 0.5 by methods ASTM E45 and ASTM A295; or according to standard ISO 683-17, total impurity content K, ≤10, and spherical carbides obtained by spheroidizing annealing, Rockwell hardness HRC is 62±1 (original text "62 1", requires confirmation against the source standard (source-text extraction)). The test disk surface should be ground but free of abrasive, and the four surface topography parameters of the test disk must satisfy the following ranges: 0.5 μm < R. < 0.650 μm, 0.035 μm < C.L.A. < 0.050 μm, 0.020 μm < Rok < 0.035 μm, 0.050 μm < Rox < 0.075 μm. The test disk diameter is 24 mm +0.5 mm, and thickness is 7.8 mm±0.1 mm (original text "7.8mm 0.Imm", requires confirmation against the source standard (source-text extraction)).
• 7.3 Cleaning solvent: meets the requirements of No. 3 solvent naphtha in GB 1922.
  • Note: Flammable, harmful to health.
• Test oil amount: 0.3 mL (see 9.1.3).

5. Instruments and equipment

• 6.1 SRV testing machine (see Figure 1): composed of a loading device, including a load regulator, temperature regulator, servo motor and power sensor, friction coefficient control device, timer, recorder/oscilloscope for monitoring the friction coefficient, chart recorder or computer data acquisition system for recording the change of friction coefficient with time, and control components for switches and heaters.
• 6.1.1 Fixture (see Figure 3): includes base (1), piezoelectric device (2), test disk fixture (3), resistance heater (4), resistance thermometer (5), reciprocating vibration drive rod (6), removable test ball fixture (7), loading rod (8), test disk (9), test ball (10).
• 6.1.2 The test disk base has a complete resistance heater, enabling the base to maintain the test temperature as low as -40°C (original text "as low as -40°C", requires confirmation against the source standard (source-text extraction)).
• 6.1.3 Test ball fixture (see Figure 4), with the test piece attached, and the corresponding fixture used.
• 6.2 Microscope: the microscope should meet the measurement requirements, equipped with a filar micrometer with divisions of 0.005 mm or equipped with a microscope readable to 0.005 mm (original text "readable to 0.005mm sand", requires confirmation against the source standard (source-text extraction)).
• 6.3 Syringe: suitable for adding 0.3 mL test oil.
• 6.4 Tweezers: straight curved tip, length about 200 mm (original text "length about 200m", requires confirmation against the source standard (source-text extraction)).
• 6.5 Torque wrench: initial torque is 0.5 N·m (original text "0.Sym Nm", requires confirmation against the source standard (source-text extraction)).
• 6.6 Ultrasonic cleaner.

6. Recommended operating conditions

• 8.1 Before starting the test, turn on the testing machine and recorder to preheat for 15 min.
• 8.2 Select the peak position that generates the friction coefficient according to the instructions.
  • Note: In most cases, this can be done by adjusting the slide switch on electronic board No.291.35.20E (on the side panel immediately behind the electronic equipment panel) and the slide switch located on the rear panel of the control unit (only for SRV1 type machines).
• 8.3 Turn the amplitude knob to "zero".
• 8.4 Set the stroke switch to the automatic position.
• 8.5 According to the instructions, set the frequency to 50 Hz, and the time to 2 h 30 s (original text "2h30s", requires confirmation against the source standard (source-text extraction)).
• 8.6 According to the instructions, set the load amplifier to the load required for the test. The test runs under constant load, with a starting load of 100 N and an increment of 100 N.
  • Note: The load amplifier of the new SRV testing machine can be set automatically.
• 8.7 According to the instructions, set the required range and calibrate the recorder, and set the required paper speed.
• Test temperature range: can be selected within the range of -40°~280°C, with selectable increments of 10°C (see 9.2.1.1).
• Test load: starting load 100 N, increment 100 N; in 9.2.1.3 the load is increased to 300 N and run for 2 h±15 s.
• Stroke: 1 mm (see precision test conditions in 11.1).
• Frequency: 50 Hz (see precision test conditions in 11.1).
• Lubricant amount: 0.3 mL (see precision test conditions in 11.1).

7. Sampling and specimen preparation

• 9.1 Install the test piece and add the test oil in the test chamber.
• 9.1.1 Wear solvent-resistant gloves, clean the test ball, test ball fixture, and test disk, and wipe the surfaces of these parts with a laboratory dense cloth already moistened with cleaning solvent. Wipe repeatedly until no black residue appears on the dense cloth. Immerse the test ball and test disk in a beaker containing cleaning solvent, and oscillate with an ultrasonic cleaner for 10 min. Air-dry the test ball fixture. Dry the test ball and test disk with a clean dense cloth, ensuring that no streaks appear on the surfaces.
• 9.1.2 Ensure that the testing machine is not loaded (the load meter reading indicates -13 N or -14 N), then install the test ball fixture (upper specimen fixture).
• 9.1.3 On a clean test disk, drip the test oil of 0.3 mL, then install the test disk (on the base), and tighten the fastening screws until resistance is felt.
• 9.1.4 Use tweezers to place the clean test ball into the disassembled, cleaned, and dried test ball fixture. Tighten the fastening screws until resistance is felt.
• 9.1.5 Install the test ball and test ball fixture in the test chamber.
• 9.1.6 Turn on the heating controller and preheat the test disk fixture to 50°.
• 9.1.7 Apply a load of 50 N, loosen the fastening screws of the test disk and test ball fixture, then immediately tighten with a torque wrench to 2.2 N·m~2.5 N·m.

8. Analysis Procedure

• 9.2 Test Run
• 9.2.1 Start of Test Run
  • 9.2.1.1 Allow the test specimen and test oil to reach and maintain the test temperature within 10 min. The test is run under constant temperature conditions. The test temperature range can be selected within the range of -40°~280°C, and can be selected in increments of 10°C.
  • 9.2.1.2 When the temperature is stable, turn on the recorder paper switch (or computer) and lower the recording pen. Press down the toggle switch until the timer starts counting, and adjust the stroke knob to the set value.
    • Note: The stroke should be checked periodically by the difference between the wear scar length on the test disk and the wear scar diameter on the test ball; the difference must be less than ±10% of the set stroke.
  • 9.2.1.3 When the timer reaches the set time, the load is increased to 300 N and run for 2 h±15 s.
• 9.2.2 Termination Evaluation
  • 9.2.2.1 When the set time is reached, the test can be automatically stopped by the timer, and the machine will automatically shut down.
    • Note 1: The power is automatically cut off at the end of the test.
    • Note 2: If due to seizure, the friction coefficient f exceeds the limit value f=0.35, the test should be terminated. If the machine cannot stop automatically at this point, it must be stopped manually.
  • 9.2.2.2 At the end of the test, turn off the heating controller, reconnect the power, and reduce the load to -13 N or -14 N for disassembly.
  • 9.2.2.3 Disassemble and clean the test ball and test disk according to 9.1.1.
• 9.3 Measurement
  • 9.3.1 Place the cleaned test ball on a suitable fixture, and use a microscope to measure the wear scar width in the sliding direction (d₁) and the wear scar width perpendicular to it (d₂), accurate to 0.01 mm. The average wear scar diameter (WSD) is the average of the two measurements (see Equation 1, Equation 2). If the wear scar diameter is less than 1.1 times the Hertzian contact diameter, the wear scar profile should be measured at the center of the wear scar in order to calculate the wear volume W. If the wear scar diameter is greater than 1.1 times the Hertzian contact diameter, the wear scar diameter is more recommended. The wear volume taken as W should use... (the original text here is severely incomplete at source-text extraction, requires confirmation against the source standard (source-text extraction)). The Hertzian contact stress and Hertzian contact diameter corresponding to different test loads are shown in Figure 5.
    • Note: Measuring the wear volume is preferable. For methods of measuring wear volume and calculating wear volume, see DIN 51834-2.
  • 9.3.2 Although no special procedure has been established, when wear analysis is required, the wear scar surface profile on the test disk can be analyzed according to the surface profilometer instructions.
  • 9.3.3 According to the line chart of the recorder or computer, measure the minimum friction coefficient and final friction coefficient (Smin, Sfinal) and the friction coefficient at 15 min, 120 min (f15min, f120min), accurate to 0.001.
  • 9.3.4 If the recorder or other output device shows strong fluctuations near the measured friction coefficient point (amplitude ≥0.005), record the average value and fluctuation value at that point; an example is shown in Figure 6.

9. Qualitative and Quantitative and Calculation Formulas

• Definition of friction coefficient (3.3): μ = F₁/F₀ (the original formula (1) is written as M= (F:/F.))
  • F₁: friction force; F₀: normal pressure.
• The geometric contact stress P at the end of the test can also be recorded as the load carrying capacity, calculated according to formula (2):
  • P = 4F₀ / (π d²) (the original formula (2) is written as "4F, / TM", requires confirmation against the source standard (source-text extraction))
  • F₀: normal pressure (test load), N;
  • P: geometric contact stress, N/mm²;
  • d: average wear scar diameter, mm.
• Average wear scar diameter (WSD): the average of the two measured values (d₁, d₂) (see 9.3.1).
• Seizure (3.16) judgment: if the duration for which the friction coefficient is greater than 0.2 exceeds 20 s or the friction coefficient >0.35, the test is marked as invalid (this standard is related to liquid lubricants, so this judgment criterion is feasible).

10. Precision

• 11.1 Precision: The precision currently used comes from DIN 51834-2:2001, which is based on the results of international laboratory cooperative tests from 1997 to 2000, test conditions: load=300 N, stroke=1 mm, temperature=50°C, lubricant amount=0.3 mL.
  • Note: For other test conditions, no other precision has been published.
  • Judge the reliability of test results according to the following provisions (95% confidence level).
• 11.1.1 Average wear scar diameter of the ball WSD
  • 11.1.1.1 Repeatability (r): The difference between two results obtained by the same operator in the same laboratory, using the same instrument, on the same test sample for repeated determinations shall not exceed 0.07 mm.
  • 11.1.1.2 Reproducibility (R): The difference between two single, independent results obtained by different operators in different laboratories, using different instruments, on the same test sample shall not exceed 0.2 mm.
• 11.1.2 Friction coefficient f
  • 11.1.2.1 Repeatability (r): The difference between two results obtained by the same operator in the same laboratory, using the same instrument, on the same test sample for repeated determinations shall not exceed 0.01.
  • 11.1.2.2 Reproducibility (R): The difference between two single, independent results obtained by different operators in different laboratories, using different instruments, on the same test sample shall not exceed 0.03.
• 11.2 For precision data measured under high temperature conditions, please refer to Appendix A.
• 11.3 Bias: Because the friction coefficient and wear scar diameter (WSD) are defined according to this standard, this standard has no bias in the evaluation of the friction and wear characteristics of lubricating oils.
• Appendix A (Informative Appendix) Precision data measured under high temperature conditions:
  • A.1 The precision in Chapter 11 of this standard was determined under the condition of 50°C, and other test temperatures outside 50°C are also allowed. The precision data listed in Table A.1 and Table A.2 were determined after international laboratory cooperative tests on two commercial oils in 2002 and 2003 under the conditions of 80°C and 120°C, and were compared with the data at 50°C.
  • Table A.1 Sixth International Laboratory Cooperative Test-2002 (test conditions: load=300 N; temperature=50°C; time=120 min; stroke=1 mm; frequency=50 Hz; ground AISI 52100 steel disk; φ=10 mm, polished AISI 52100 steel ball):
    • RR2002 220 Industrial lubricating oil A, 120°C: friction coefficient fEND degrees of freedom 31, mean 0.0895, standard deviation ±0.0095, reproducibility (R) 0.0287 (set value: ≤0.03); ball wear scar diameter WK- average/mm degrees of freedom 29, mean 0.4824, standard deviation ±0.0226, reproducibility (R) 0.0654 (set value: ≤0.2)
    • RR2002 220 Industrial lubricating oil A, 80°C: friction coefficient fEND degrees of freedom 29, mean 0.0919, standard deviation ±0.00701, reproducibility (R) 0.0203 (set value: ≤0.03); ball wear scar diameter WK- average/mm degrees of freedom 26, mean 0.477, standard deviation ±0.0261, reproducibility (R) 0.00758 (set value: ≤0.2)
    • RR2001 220 Industrial lubricating oil A, 50°C: friction coefficient fEND degrees of freedom 33, mean 0.1006, standard deviation ±0.0128, repeatability (r) 0.0132 (set value: ≤0.01), reproducibility (R) 0.035 (set value: ≤0.03); ball wear scar diameter WK- average/mm degrees of freedom 34, mean 0.4683, standard deviation ±0.0216, repeatability (r) 0.00778 (set value: ≤0.01), reproducibility (R) 0.0266 (set value: ≤0.07), reproducibility (R) 0.062 (set value: ≤0.2)
    • Note: The number of tests for each test oil sample is >55 times, and statistical calculations are performed using ASTM D2PP software.
  • Table A.2 Seventh International Laboratory Interlaboratory Test - 2003 (Test conditions: load = 300 N; temperature = 50°C; time = 120 min; stroke = 1 mm; frequency = 50 Hz; ground AISI 52100 steel disc; φ=10 mm, polished AISI 52100 steel ball):
    • RR2003 220 industrial lubricating oil B, 120°C: coefficient of friction fEND degrees of freedom 23, mean 0.0986, standard deviation ±0.00839, reproducibility (R) 0.0246 (set value: ≤0.03); wear scar diameter of ball WK- mean/mm degrees of freedom 27, mean 0.4835, standard deviation ±0.0189, reproducibility (R) 0.0548 (specification requirement: ≤0.2)
    • RR2003 220 industrial lubricating oil B, 80°C: coefficient of friction fEND degrees of freedom 24, mean 0.1038, standard deviation ±0.00699, reproducibility (R) 0.0195 (specification requirement: ≤0.03); wear scar diameter of ball WK- mean/mm degrees of freedom 27, mean 0.403, standard deviation ±0.0257, reproducibility (R) 0.0747 (specification requirement: ≤0.2)
    • RR2000 220 industrial lubricating oil B, 50°C: coefficient of friction fEND degrees of freedom 39, mean 0.1105, standard deviation ±0.00891, reproducibility (R) 0.02540 (specification requirement: ≤0.03); wear scar diameter of ball WK- mean/mm degrees of freedom 45, mean 0.47397, standard deviation ±0.0403, reproducibility (R) 0.1146 (specification requirement: ≤0.2)
    • Table A.2 (continued) statistical parameters (D2PP) repeatability (r): coefficient of friction fEND 0.00491 (specification requirement: ≤0.01); wear scar diameter of ball WK- mean/mm 0.0326 (specification requirement: ≤0.07); coefficient of friction fEND 0.00772 (specification requirement: ≤0.01); wear scar diameter of ball WK- mean/mm 0.6680 (specification requirement: ≤0.07)
    • Note: For each test oil sample, the number of tests > 43 times, statistical calculations are performed using ASTM D2PP software (test conditions: load = 300 N; temperature = 50°C; time = 120 min; stroke = 1 mm; frequency = 50 Hz; ground AISI 52100 steel disc; φ=10 mm, polished AISI 52100 steel ball).

11. Report

• 10.1 The report shall include the following information:
  • 10.1.1 All parameters for evaluating the material;
  • 10.1.2 Test temperature, °C;
  • 10.1.3 Test running-in load, N;
  • 10.1.4 Test load, N;
  • 10.1.5 Stroke, mm;
  • 10.1.6 Ball material;
  • 10.1.7 Disc material;
  • 10.1.8 Test oil name.
• 10.2 Report the wear scar diameters of the test balls (d₁, d₂) and their mean value WSD.
• 10.3 Report all measured results of the coefficient of friction, Smin, Sfinal, f15, f50, f500, f100 and the magnitude of strong fluctuations in the coefficient of friction. When there are specific requirements, attach a copy of the friction record.
• 10.4 If the wear scar depth of the test disc was measured, the wear scar depth of the test disc shall be reported.

12. Normative references

• GB 1922 Solvent naphtha for paints and cleaning
• GB/T 18778.2 Geometrical product specifications (GPS) Surface texture: Profile method — Surfaces having defined functional characteristics — Part 2: Characterization of height characteristics by linearized bearing ratio curve (GB/T 18778.2—2003, ISO 13565-2:1996, IDT)
• ISO 683-17 Heat-treated steels, alloy steels and free-cutting steels — Part 17: Rolling bearing steels
• ASTM A295 Technical specifications for high-carbon anti-wear bearing steel
• ASTM E45 Method for evaluating the content of non-metallic inclusions in steel
• DIN 51834-2-2001 Linear reciprocating tribological testing — Part 2: Determination of friction and wear values of lubricating oils
• DIN 51834-3 Linear reciprocating tribological testing — Part 3: Determination of friction characteristics of the synergistic effect between materials and lubricants
• ASTM D6425-05 Determination of friction and wear performance of extreme pressure lubricating oils (SRV testing machine method) (modified adoption of the original standard)

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick Q&A