SH/T 0577-1993 Determination of high-temperature friction and wear performance of railway diesel engine oils (bronze-steel method)

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Card type: Test method

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

• Standard number: SH/T 0577-93
• Full name: Determination of high-temperature friction and wear performance of railway diesel engine oils (bronze-steel method)
• English name: not provided in the available source
• Replacement relationship: not provided in the available source
• Approval/implementation: approved by China Petrochemical Corporation 1993-08-19, implemented on 1994-05-01

2. Scope of application and non-applicability

• This standard specifies the determination method for high-temperature friction and wear performance of railway diesel engine oils.
• This standard is applicable to the determination of high-temperature friction and wear performance of railway diesel engine oils.
• Not applicable: not provided in the available source.

3. Method principle

This method includes the A method and the B method; the tester selects the A method or the B method according to the oil performance.

3.1 A method One steel ball is pressed tightly against three bronze discs fixed in an oil cup and rotates under a load of 196N±2N and a speed of 600r/min±20r/min. The contact geometry between the steel ball and the bronze discs is the same as the four-ball contact form; in each stage of the test, the contact point is always immersed in the lubricating oil. The test starts at 93℃±3℃, and for each increase of 28℃ the test is conducted at 5min, for a total of seven stages, with the final stage test temperature being 260℃±3℃. At each stage, the friction coefficient is measured and recorded; at the end of the seven stages, the wear scar diameters of the bronze discs are measured and the average value is calculated. The high-temperature friction and wear performance of the test oil is evaluated by the product of the maximum friction coefficient and the average wear scar diameter, and by the temperature at which the maximum friction coefficient occurs.

3.2 B method In this method, the first stage test temperature is 93℃±3℃, and for each increase of 28℃ the test is conducted at 5min, for a total of four stages, with the final stage test temperature being 177℃±3℃. The test results do not include the temperature at which the maximum friction coefficient occurs. All other aspects are the same as the A method.

4. Reagents and materials (purity / preparation)

• 4.2.1 Washing gasoline: meets the requirements of GB 1787.
• 4.2.2 Petroleum ether: boiling range 60～90℃, analytical reagent; or solvent naphtha (meets the requirements of GB 1922 90).
• 4.2.3 Metallographic abrasive paper: model 02 (M 20).
• 4.3 Test specimens
  • 4.3.1 Test steel ball: steel ball specially for four-ball machine, diameter 12.7 mm, Rockwell hardness HRC 64～66. Material GCr15.
  • 4.3.2 Bronze disc: material is high-lead tin bronze (80/10/10 continuously cast bronze, copper 78%～81%, tin 9.3%～10.7%, lead 8.3%～10.7%), diameter 6.35±0.05 mm (requires confirmation against the source standard (source-text extraction): the source text is “6.35[unreadable character]05”), thickness 1.59±? mm (requires confirmation against the source standard (source-text extraction): the source text is “1.59[unreadable characters]nun”), Brinell hardness between HB 90～100, surface roughness Rq 0.63～2.50 μm, Rz 3.2～10 μm (requires confirmation against the source standard (source-text extraction): the source text is “Rg0.63[unreadable separator]2.50}un, R,3.2[unreadable separator]lofun”), machined on a precision lathe.

5. Instruments and equipment

• 4.1.1 Testing machine: when using the A method, the test oil temperature can be heated to 260℃±3℃; when using the B method, the test oil temperature can be heated to 177℃±3℃; a wear four-ball machine with a friction force plotting system.
• 4.1.2 Microscope: magnification 25×, scale division value 0.01mm.
• Others: heating chamber, oil cup, upper chuck, spindle, friction force recorder, temperature controller, timer, etc. (see Section 6 operating procedures).

6. Recommended operating conditions

• Load: preload 588N; test load 196N±2N.
• Rotational speed: 600r/min±20r/min.
• Time per stage test: 5min.
• Test temperature sequence:
  • A method: 93, 121, 149, 177, 204, 232, 260℃.
  • B method: 93, 121, 149, 177℃.
• Test temperature error: ±3℃.
• Testing machine preheating: 15min.

7. Sampling and specimen preparation

• 5.1.1 Select three bronze discs and one steel ball, clean them successively with washing gasoline and petroleum ether, and blow dry with dry air. The fixture in contact with the test specimen shall also be cleaned in the same way and dried.
• 5.1.2 Install the bronze discs into the holes of the oil cup. It is permissible to polish the bronze discs along the circumferential direction with metallographic abrasive paper so that they fit closely into the holes of the oil cup.
• 5.1.3 Use clean silk to pick up the steel ball and install it into the upper chuck, and install the upper chuck onto the spindle.
• 5.1.4 Install the oil cup into the heating chamber.
• 5.1.5 Add the test oil into the oil cup so that the test oil covers above the contact point between the steel ball and the bronze discs.
• 5.2 Testing machine preparation
  • 5.2.1 Adjust the spindle drive system so that the rotational speed can reach 600r/min±20r/min.
  • 5.2.2 Turn on the power to preheat the testing machine for 15min.
  • 5.2.3 Calibrate the friction force meter (for the calibration method, refer to the testing machine manual).
  • 5.2.4 Adjust the recorder (for the adjustment method, refer to the recorder manual).

8. Analysis procedure

• 6.1 Fix the oil cup, apply a preload of 588N to the test specimen, and manually drive the spindle to rotate one revolution.
• 6.2 Reduce the load to the test load of 196N±2N.
• 6.3 Adjust the timer to 5min.
• 6.4 Set the test temperatures on the temperature controller according to the test temperature sequence specified in clause 6.9.
• 6.5 Connect the friction force measurement system.
• 6.6 When the temperature reaches the test temperature, first start the friction force recorder, then start the spindle motor. When 5min ends, the testing machine stops running, and the maximum friction force is recorded.
• 6.7 Turn off the recorder, heater, and timer in sequence.
• 6.8 Repeat the steps from clause 6.3 to clause 6.7 to carry out the next stage test.
• 6.9 The test temperature error is ±3℃, and the sequence is: A method: 93, 121, 149, 177, 204, 232, 260℃; B method: 93, 121, 149, 177℃.
• 6.10 After completing the final stage test, remove the load, disconnect the temperature and friction force measurement systems, take off the oil cup, and after the oil cup has cooled, pour out the test oil.
• 6.11 Remove the chuck from the spindle and remove the steel ball.
• 6.12 Clean the oil cup and bronze discs with washing gasoline, remove copper debris around the wear scars with bamboo or wooden tongs, and under the microscope measure the wear scar diameters of the three bronze discs along the direction of the wear scar striations and perpendicular to it, recording six measurement results.
• 6.13 Clean the upper chuck, oil cup, and test fixture successively with washing gasoline and petroleum ether, and blow dry with dry air.

9. Qualitative and quantitative determination and calculation formulas

• 7.1 Take the arithmetic mean of the six measured values of the wear scar diameters of the three bronze discs, and use the arithmetic mean as the average wear scar diameter.
• 7.2 Multiply the maximum friction force recorded under each stage test in clause 6.6 by a constant value and divide by the test load to obtain the friction coefficient. Note: the constant value can be found in the testing machine manual.
• 7.3 Take the maximum value calculated in clause 7.2 as the maximum friction coefficient.
• 7.4 Multiply the maximum friction coefficient by the average wear scar diameter to obtain the friction evaluation grade.
• 7.5 The test temperature of the stage corresponding to the maximum friction coefficient is defined as the temperature at which the maximum friction coefficient occurs.

10. Precision

Use the following values to judge the reliability of the results (95% confidence level).

9.1 A method

• 9.1.1 Repeatability: the difference between two consecutive determination results obtained by the same operator in the same laboratory using the same testing machine on the same test oil shall not exceed the value in Table 1.
• 9.1.2 Reproducibility: the difference between results obtained by different operators in different laboratories using the same type of testing machine on the same test oil sample shall not exceed the value in Table 1.

Table 1 Precision specifications (A method)

9.2 B method

• 9.2.1 Repeatability: the difference between two consecutive determination results obtained by the same operator in the same laboratory using the same testing machine on the same test oil shall not exceed the value in Table 2.
• 9.2.2 Reproducibility: the difference between results obtained by different operators in different laboratories using the same type of testing machine on the same test oil shall not exceed the value in Table 2.

Table 2 Precision specifications (B method)

11. Report

• 8.1 A method
  • 8.1.1 Average wear scar diameter of the bronze discs, accurate to 0.01mm.
  • 8.1.2 Temperature at which the maximum friction coefficient occurs, accurate to 1℃.
  • 8.1.3 Friction evaluation grade, accurate to 0.01mm.
• 8.2 B method
  • The B method reports the two items 8.1.1 and 8.1.3.

12. Referenced documents

• GB 1787 (editor's note: current standard number GB 1787, current standard name: aviation gasoline)
• GB 1922 (the source citation is “GB 1922 90”, the specific name is not provided in the available source)
• Note: the “Referenced standards” section in the source text source-text extraction is “GB 1787 [unreadable character]1922 washing gasoline / solvent oil”, there is noise, requires confirmation against the source standard (source-text extraction).

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