SH/T 0201-1992 Determination of friction coefficient of liquid lubricants (Falex pin and V block method)

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Card type: Test method

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

• Standard number: SH/T 0201-92
• Chinese full name: Determination of friction coefficient of liquid lubricants (Falex pin and V block method)
• English name: not provided in the available source
• Replacement relationship: replaces ZB F34 020-89 (the source writes “replaces ZB F34 020-89”, the line-break doubt for source-text extraction requires confirmation against the source standard)
• Approval/implementation: approved by China Petrochemical Corporation 1992-05-20, implemented on 1992-05-20

2. Scope of application and non-applicability

• Scope of application: This standard specifies the method for determining the friction coefficient of liquid lubricants using the Falex pin and V block testing machine; it is applicable to evaluating the lubricating performance of various liquid lubricants under specified test conditions.
• Not applicable: not provided in the available source.

3. Method principle

A steel test pin is rotated against the V-shaped groove surfaces of two stationary V blocks immersed in a liquid lubricant sample at 290 r/min rotational speed. A certain load is applied by a ratchet mechanism, the friction torque of the rotating test pin is measured with a torque meter, and the friction coefficient is calculated from the corrected true torque and true load.

4. Reagents and materials (purity / preparation)

• 4.2.4 solvent naphtha: meets the requirements of No. 190 in GB 1922.
• 4.2.5 solvent naphtha: meets No. 90 in GB 1922, or petroleum ether 60～90 ℃, analytical reagent.
• 4.2.1 V block: made of free-cutting structural steel, Rockwell hardness HRC 20～24, surface roughness 0.13～0.25 μm (root mean square value), geometric dimensions as shown in a of Figure 3, main chemical composition as shown in Table 1.
• 4.2.2 test pin: made of alloy structural steel, Rockwell hardness HRB 87～90, surface roughness 0.13～0.25 μm (root mean square value), geometric dimensions as shown in b of Figure 3, main chemical composition as shown in Table 1.
• 4.2.3 shear pin: brass, geometric dimensions as shown in c of Figure 3, main chemical composition as shown in Table 1.
• Table 1 Main chemical composition of test piece materials (%):
  • V block: C 0.32～0.39; Si < 0.20; Mn 1.35～1.65; S 0.08～0.13; P < 0.04.
  • Test pin: C 0.33～0.38; Si 0.20～0.35; Mn 0.60～0.80; S < 0.040; P < 0.040; Cr 0.55～0.75; Ni 1.10～1.40.
  • Shear pin: contains copper 95.0～97.0, iron 0.10 (upper limit not provided in the available source, requires confirmation against the source standard (source-text extraction)).
• Standard inspection copper block (abbreviated as standard block): annealed soft copper, Brinell hardness HB 37～390 (as written in the source, suspected to be HB 37～39 or a similar range, requires confirmation against the source standard (source-text extraction)).

5. Instruments and equipment

• 4.1.1 Falex pin and V block testing machine, schematic diagram of test piece composition as shown in Figure 1.
• 4.1.2 not provided in the available source (source-text extraction missing).
• 4.1.3 Set screw: with a steel ball for a Brinell hardness tester having a diameter of 10 mm.
• 4.1.4 Support plug.
• 4.1.5 Standard inspection copper block (abbreviated as standard block): annealed soft copper, Brinell hardness HB 37～390 (requires confirmation against the source standard (source-text extraction)).
• 4.1.6 Microscope: with scale, division value 0.01 mm.
• 4.1.7 Thermometer: 0～100 ℃, division value 1 ℃.
• 4.1.8 Steel ruler: length 150 mm.
• 4.1.9 Torque calibration mechanism, as shown in Figure 2 (1— torque sensor; 2— pulley frame; 3— pulley; 4— weights; 5— pull wire; 6— force arm rod; 7— rotating body).
• Stopwatch (the source lists it near 4.1.2, numbering requires confirmation against the source standard (source-text extraction)).

6. Recommended operating conditions

• Test pin rotational speed: 290 r/min.
• Break-in load: true load 890 N (200 lbf), break-in 5 min.
• Test load: true load 1334 N (300 lbf), run 15 min.
• Sample temperature: if below 52 ℃, heat with a heating platen to 55 ℃±3 ℃; if above 58 ℃, cool in air to 55 ℃±3 ℃.
• Sample amount: 60 mL.
• Torque calibration: add weights 200 g, run 15 min; increase weights in 5 stages, each stage increasing by 200 g.

7. Sampling and sample preparation

• 7.1 Thoroughly clean the V block, test pin, shear pin, oil cup, loading clamp, and other parts that contact the sample with solvent naphtha and petroleum ether in sequence, and dry in air.
• 7.2 Handle the cleaned test pieces carefully to prevent contamination, especially avoid contact of the contact surfaces of the V block and test pin with fingers.
• 7.3 Insert the test pin into the sleeve at the lower end of the testing machine spindle, and lock it with a brass shear pin, as shown in Figure 1.
• 7.4 Insert the V block into the hole of the loading clamp jaw, let the V block contact the test pin, and align the V groove with the axis of the test pin.
• 7.5 Pour 60 mL sample into the oil cup, and place the oil cup on the heating platen of the testing machine so that the test pieces are immersed in the sample. If the sample viscosity is high, slightly open the jaws so that the sample covers the friction surfaces.
• 7.6 Install the load gauge ratchet loading assembly on the loading lever arm.

8. Analysis steps

• 8.1 Start the motor, engage the loading pawl with the ratchet, automatically increase the load until the true load reaches 890 N (200 lbf), disengage the pawl from the ratchet, and break in at this load for 5 min.
• 8.2 Stop the motor, remove the load, and measure the temperature of the sample in the oil cup. If the temperature is below 52 ℃, heat the sample with the heating platen to 55 ℃±3 ℃. If the temperature is above 58 ℃, cool in air to 55 ℃±3 ℃.
• 8.3 Turn the loading ratchet by hand to eliminate the slack state of the loading mechanism, so that the load gauge reading is zero, and the torque gauge reading is also zero or adjusted to zero.
• 8.4 Start the motor, engage the loading ratchet, automatically increase the load until the true load is 1334 N (300 lbf), disengage the pawl, run at this load for 15 min, and let the torque gauge automatically record the torque. If necessary, gently turn the ratchet by hand to keep the load constant.
• 8.5 After the test ends, remove the load, stop the motor, take off the oil cup, discard the sample, remove the load gauge ratchet loading mechanism and test pieces, and clean the testing machine.
• 9.1 The source is located before Chapter 9, and the content is “[garbled text], F months without testing [garbled interval], or after every 10 tests: inspect and calibrate the testing machine; see Appendix A” (source-text extraction noise is severe, suspected to be “no tests for 6 months or more, or after every 10 tests: inspect and calibrate the testing machine; see Appendix A”, requires confirmation against the source standard (source-text extraction)).

9. Qualitative and quantitative determination and calculation formulas

• 9.2 Calculate the average value recorded by the torque gauge, and use the torque calibration curve prepared in clause 6.5 to convert this average value into a true torque value.
• Friction coefficient μ is calculated according to formula (2): μ = 116.8 T / (Ld) …… (2) Where: T— true torque value, N·m; Ld— true load value, N.
• Since the true load used in the test is 1334 N, formula (2) can be simplified to formula (3): μ = 0.08765 T …… (3)
• Note: When the load and torque use imperial units, i.e., pound-force and pound-force·inch respectively, the calculation formula is: μ = 2.97767 T / Ld (the formula number and form in the source require confirmation against the source standard (source-text extraction))
• 6.4 Calculation of true torque value T(N·m): T = 9.81 L (Q + W) …… (1) Where: Q— mass of weight pan, kg; W— mass of weights, kg; 9.81— gravitational acceleration, m/s² (the source writes “9. 81,./.2”, requires confirmation against the source standard (source-text extraction)); L— force arm, m.

10. Precision

Judge the reliability of test results according to the following provisions (95% confidence level).

• 10.1 Repeatability: the difference between two consecutive test results obtained by the same operator using the same equipment in the same laboratory shall not exceed 7% of the arithmetic mean.
• 10.2 Reproducibility: the difference between test results obtained by different operators using the same type of equipment in different laboratories shall not exceed 10% of the arithmetic mean.
• Note: The precision of this standard is determined based on statistical experimental data from 1987 year using 9 test samples in 6 laboratories, derived through mathematical statistics according to GB/T 6683.

11. Report

Take the arithmetic mean of two consecutive test results as the test result, and fill it in the report form shown in Appendix B.

• Appendix B Test Record Table (Reference) Table B1 includes: number, sample name, commissioning unit, date; items: room temperature (℃), initial oil temperature (℃), gauge load (N/lbf), true load (N/lbf), gauge torque (N·m/lbf·in), true torque (N·m/lbf·in), friction coefficient, remarks; first time, second time, average; tester (signature).
• Appendix A Testing Machine Inspection and Calibration (Supplementary): Using two standard oils FL and FH, if the arithmetic mean of two consecutive test results according to Chapters 7 to 9 of this standard falls within the following ranges, the testing machine is considered to be in normal condition, and the test conditions and test operation methods are correct.
  • FL: friction coefficient 0.083～0.092
  • FH: friction coefficient 0.154～0.170

12. Normative References

• GB 1922 Solvent naphtha
• GB/T 6683 Determination and application of precision of test methods for petroleum products
• Editor's note: original standard number GB/T 6683, current standard number GB/T 6683 (source-text extraction displayed as "f; day/T bite i683", requires confirmation against the source standard (source-text extraction)), current standard name: Determination method for precision data of test methods for petroleum products.

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