NB/SH/T 0189-2017 Determination of anti-wear properties of lubricating oils — Four-ball method

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Card type: Test method

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

• Standard number: NB/SH/T 0189—2017
• Chinese full title: Determination of anti-wear properties of lubricating oils — Four-ball method
• English title: Standard test method for wear preventive characteristics of lubricating fluid—four-ball method
• Replacement relationship: replaces SH/T 0189—1992 "Determination method for anti-wear properties of lubricating oils (four-ball machine method)"
• Adoption relationship: modified adoption by the redrafting method of ASTM D4172-94 (2016) "Determination method for anti-wear properties of lubricating oils (four-ball method)"
• Previous versions: SH/T 0189—1992
• Publication/implementation: published on 2017-12-27, implemented on 2018-06-01
• Issuing authority: National Energy Administration
• Drafting rules: drafted in accordance with the rules given in GB/T 1.1—2009
• Custodianship: Subcommittee on Petroleum Fuels and Lubricants of the National Technical Committee for Standardization of Petroleum Products and Lubricants (SAC/TC280/SC1)
• Proposed by: China Petrochemical Corporation
• Drafting organizations: Lanzhou Lubricating Oil Research and Development Center of PetroChina Company Limited, Research Institute of Petroleum Processing of China Petroleum & Chemical Corporation, Beijing Research Institute of Sinopec Lubricant Company Limited
• Main drafters: Li Tong, Lei Ailian, Ding Fangling, Yang He, Hu Gang

2. Scope of application and non-applicability

• This standard specifies a method for determining the anti-wear properties of lubricating oils using a four-ball testing machine.
• It is applicable to evaluating the anti-wear properties of lubricating oils, including three test conditions: A, B, and C.
• Test condition C is mainly used to evaluate the anti-wear properties of industrial enclosed gear oil L-CKD, and may also be used to evaluate the anti-wear properties of other lubricating oils.
• For the method of evaluating the anti-wear properties of lubricating grease using the same testing machine, see SH/T 0204.
• Not applicable: This standard did not use water-based fluid as test oil for precision statistical tests (Note 2 to Chapter 4).

3. Method principle

Three steel balls with a diameter of 12.7mm are clamped in an oil box and immersed in the test oil. Another steel ball of the same diameter is placed directly on top of the three balls, a specified load is applied, and under the action of the test force, it forms "three-point contact" with the three lower steel balls in the oil box. When the test oil reaches the specified test temperature, the top ball rotates at the specified speed for 60min, after which the test ends. The wear scar diameters of the three lower steel balls are measured, and the average value of their wear scar diameters is taken to evaluate the anti-wear properties of the lubricating oil.

4. Reagents and materials (purity / preparation)

• 7.1 Test steel balls: material conforms to the E-52100 chromium alloy steel balls in the United States ANSI standard, or conforms to the high-carbon chromium bearing steel balls in GB/T 308.1—2013, with a diameter of 12.7mm and a hardness of HRC 61~66.
• 7.2 Cleaning solvents: solvent naphtha conforming to the requirements for No. 2 solvent naphtha in GB 1922—2006, and petroleum ether conforming to the requirements of GB/T 15894.
• Appendix A (normative appendix) Precautions:
  • A.1 Petroleum ether: A.1.1 harmful, vapors can cause flash fire; A.1.2 keep away from heat, sparks, and open flames; A.1.3 store in a closed container; A.1.4 avoid generating vapors, keep away from ignition sources, especially electrical equipment and heat sources; A.1.5 avoid prolonged inhalation of vapors; A.1.6 avoid prolonged skin contact.
  • A.2 Cleaning solvent: A.2.1 vapors can cause flash fire; A.2.2 keep away from heat, sparks, and open flames; A.2.3 store in a closed container; A.2.4 avoid generating vapors, keep away from ignition sources, especially electrical equipment and heat sources; A.2.5 avoid prolonged inhalation of vapors; A.2.6 avoid prolonged skin contact.

5. Apparatus and equipment

• 6.1 Four-ball wear testing machine
  • 6.1.1 The construction of the test section of the four-ball machine is shown in Figure 1 (original Figure 4 Schematic diagram of four-ball contact: motor-driven upper steel ball, 3 lower steel ball fixture, thermocouple, heating wire). Note: First, a distinction should be made between a four-ball extreme pressure testing machine and a four-ball wear testing machine; the four-ball extreme pressure testing machine is designed for testing under heavy loads and has lower sensitivity than a wear testing machine.
  • 6.1.2 Performance requirements for the four-ball testing machine: the maximum speed of the testing machine can reach 2000r/min, with a control accuracy not lower than 5%; the controlled temperature of the test oil can reach 80°C; the test load can reach 400N±2N.
• 6.2 Microscope: capable of measuring the wear scar diameters formed on the surfaces of the three lower steel balls, with a resolution requirement of 0.01mm. If measurement can be performed directly without removing the steel balls from the oil box, efficiency will be higher.

6. Recommended operating conditions

The test conditions are shown in Table 1.

Table 1 Three test conditions

Note (Note 2 to Chapter 4): The four-ball testing machine may be operated under other parameters different from those in Table 1, but the precision specified in Chapter 12 may differ. This standard did not use water-based fluid as test oil for precision statistical tests.

7. Sampling and test specimen preparation

Not provided in the available source.

8. Analytical procedure

• 9 Preparation of apparatus
  • 9.1 Start the drive motor, adjust the spindle speed to the speed specified by the test conditions; during the test, the precision control should be ±60r/min.
  • 9.2 Adjust the oil temperature controller so that the test oil temperature is the specified test temperature; during the test, the precision control should be ±2°C.
  • 9.3 When using an automatic timer, the timing precision in the 60min test should be ±1min.
  • 9.4 With all test steel balls, the test oil box, and the heating jacket in place, the loading mechanism should be balanced at zero. The load measuring mechanism should be able to detect a change in the loading mechanism when a force of 19.6N is added or removed.
• 10 Test procedure
  • 10.1 According to the requirements for cleaning solvents specified in clause 7.2, first use solvent naphtha, then petroleum ether, to carefully clean the four test steel balls, the upper steel ball fixture, the oil box, and all parts that come into contact with the test oil. The test steel balls may finally be wiped with a clean silk cloth or unused absorbent cotton balls. Once the steel balls have been cleaned, they must not be touched by hand, and no solvent residue may remain on the steel balls.
  • 10.2 Install one clean steel ball in the fixture at the lower end of the spindle.
  • 10.3 Install the other three clean steel balls in the oil box and tighten with a special wrench; the tightening torque is approximately 33.8N·m~67.7N·m.
  • 10.4 Pour the test oil into the oil box so that the test oil exceeds the top of the steel balls by at least 3mm. After a period of time, once the test oil has filled the gaps in the oil cup assembly, observe the test oil level to ensure it meets the requirements. In interlaboratory round-robin tests, issues related to the effect of test oil level on the friction and wear properties of the test oil were not studied.
  • 10.5 Place the oil box on the oil box seat and slowly apply the test load to the load specified by the test conditions, avoiding impact.
  • 10.6 Start the heater and heat the test oil to the test temperature ±2°C. The heating voltage and proportional controller deviation should ensure that the temperature control precision is within the above required range.
  • 10.7 After the test temperature is reached, start the motor so that the spindle speed reaches the speed specified by the set test conditions. A four-ball machine using proportional automatic control will automatically start the test before the test temperature is reached. The proportional control range should be set so that the controller starts the test when the temperature is at least 2°C close to the test oil temperature.
  • 10.8 When the test time reaches 60min±1min, stop heating and turn off the motor, remove the load, take out the oil box, and pour off the test oil.
  • 10.9 Use a microscope to measure the wear scar diameters of the three lower steel balls in the oil box, accurate to 0.01mm. Either of the following two methods may be selected for measurement:
    • 10.9.1 Method 1: Wipe the wear scar area clean with a paper towel and place the oil cup on a dedicated microscope. Measure the wear scar diameter on each steel ball twice, once along the direction of the wear scar and once perpendicular to the first. Report the arithmetic mean of the six measurements of the wear scar diameters of the three steel balls in units of mm.
    • 10.9.2 Method 2: Remove the steel balls from the oil cup and wipe the wear scar area clean. Measure the wear scar diameter on each steel ball twice, once along the direction of the wear scar and once perpendicular to the first. If the wear scar is elliptical, measure the wear scar diameter once parallel to the wear scar and once perpendicular to the wear scar. During measurement, ensure that the line of sight is perpendicular to the measurement surface. As in 10.9.1, report the arithmetic mean of the six measurements of the wear scar diameters of the three steel balls in units of mm.
    • 10.9.3 If the arithmetic mean of the two measurements of the wear scar diameter of any one steel ball deviates from the average of the six measurements by more than 0.04mm, the axial alignment of the upper steel ball and the oil box should be checked.

9. Qualitative and quantitative determination and calculation formula

• 11 Reporting of results: Report the arithmetic mean of the six measurement results of the wear scar diameter in clause 10.9, in millimeters, accurate to 0.01mm. The test speed, load, temperature, and test time should be stated.
• Calculation formula: Not provided in the available source (expressed as the arithmetic mean of the six measured wear scar diameters).

10. Precision

• 12.1 Precision: Judge the reliability of the test results according to the following provisions (95% confidence level).
  • Note: The precision data of this standard were obtained from tests conducted by 13 laboratories on 5 test oils under test condition A and test condition B specified in Chapter 8. For detailed information on the test oils and the average wear scar diameter data obtained under the two test conditions, see Appendix B. It has been verified by testing that test condition C can also meet the precision specified in this standard.
  • 12.1.1 Repeatability, r: For two test results obtained by the same operator in the same laboratory using the same apparatus, according to the same method, on the same test specimen in continuous determinations, the difference between the two results should not exceed 0.12mm.
  • 12.1.2 Reproducibility, R: For two single, independent test results obtained by different operators in different laboratories using different apparatus, according to the same method, on the same test specimen, the difference between the two results should not exceed 0.28mm.
• 12.2 Bias: The wear scar diameter in this standard is defined by this test method; therefore, this standard method has no bias.

11. Report

Report the arithmetic mean of six measurements of the wear scar diameter in 10.9, in millimeters, accurate to 0.01mm. The test speed, load, temperature, and test duration shall be noted.

12. Normative references

• GB/T 308.1—2013 Rolling bearings — Balls — Part 1: Steel balls
• GB 1922—2006 Solvent naphtha for paints and cleaning
• GB/T 15894 Chemical reagent — Petroleum ether (the source text writes CB/T 15894, requires confirmation against the source standard (source-text extraction))
• GB/T 17754—2012 Tribology terminology
• SH/T 0204 Determination of anti-wear properties of lubricating grease (four-ball machine method)
• ASTM D4172-94 (2016) (modified adoption of the source 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-reference Q&A