SH/T 0520-1992 Evaluation Method for Thermal Oxidation Stability of Vehicle Gear Oils (L-60 Method)

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Card type: Test method

1. Method Number / Full Name / English Name / Replacement Relationship

• Standard number: SH/T 0520-92
• Chinese full name: Evaluation Method for Thermal Oxidation Stability of Vehicle Gear Oils (L-60 Method)
• English name: not provided in the available source
• Replacement relationship: not provided in the available source
• Approval/implementation: approved by China Petrochemical Corporation 1992-07-23, implemented on 1993-07-01
• Equivalent adoption: United States Federal Standard FS 791B 2504 "Test Method for Evaluating the Thermal Oxidation Stability Performance of Automotive Gear Oils" (see additional notes)

2. Scope of Application and Non-Applicability

• This standard specifies the method for evaluating the thermal oxidation stability of vehicle gear oils using the L-60 method.
• This standard is applicable for evaluating the degree of deterioration of L-CLE vehicle gear oils under severe high-temperature oxidation conditions.
• Not applicable: not provided in the available source.

3. Method Principle

Add 120 mL of sample into an indirectly heated gearbox. The gearbox contains two spur gears and one test bearing. Operate under specified load and copper strip catalytic conditions. Air is bubbled through the sample in the gearbox at a flow rate of 1.1 L/h. The oil temperature is maintained at 162.8℃±0.6℃, and operation is continuous for 50 h. After the test, evaluate the thermal oxidation stability of the vehicle gear oil by examining the test parts and the post-test sample.

4. Reagents and Materials (Purity / Preparation)

• 4.1.9 Cleaning agent: Oakite 811 cleaning agent or Samsung water-based scouring pad, etc.
• 4.1.10 Solvent naphtha: meets the requirements of GB 1922 NY 190.
• 4.1.11 Toluene: meets the requirements of GB 684.
• 4.1.12 Ethanol: meets the requirements of GB 679.
• 4.1.13 360 water sandpaper and scouring cloth.
• 4.1.14 Vaseline: meets the requirements of SH/T 0039.
• 4.1.15 Silica gel.
• 4.1.16 Cork gasket thickness 1.5 mm.
• 4.1.17 White paper gasket thickness 0.125 mm.
• 4.1.6 Copper strip catalyst: two cold-rolled electrolytic copper strips, dimensions 46 mm×14 mm×1.5 mm.
• 4.1.7 Test gears: one pair of cylindrical spur gears for machine tools, one with GA34 number of teeth 34, tooth width 9.5 mm, the other with GA50 number of teeth 50, tooth width 9.5 mm.
• 4.1.8 Test bearing: new non-standard R-14 ball bearing.
• 4.1.4 Dry compressed air.
• Purity/preparation details: not provided in the available source (except as meeting the above standard requirements).

5. Instruments and Equipment

• 4.1 Figure 1—2 is a schematic diagram of the test apparatus and a cross-sectional view of the gearbox installation.
• 4.1.1 Gearbox: the box contains a new test bearing, a pair of new test gears, and two copper strip catalysts.
• 4.1.2 Temperature control system: consists of an insulated heating box, a circulating blower, and two thermocouple sensors, equipped with temperature control, display, and recording instruments.
• 4.1.3 DC generator system: this system is equipped with instruments for adjusting excitation current and measuring output power. The DC generator is 12 V, 45 A, capable of applying a load of 128 W to the test gears.
• 4.1.5 Air flow regulator: a flow meter capable of controlling air flow at 1.1 L/h under a pressure of 7 kPa.
• Figure 1 Schematic diagram of the test apparatus (components: 1— test gearbox; 2— heater; 3— base; 4— blower motor; 5— generator; 6—V type belt; 7— drive motor; 8— bearing housing; 9— air box thermocouple; 10— heating box; 11— radiant heat baffle; 12— gearbox exhaust pipe; 13— viewing window; 14— air inlet pipe; 15— test oil thermocouple)
• Figure 2 Cross-sectional view of the gearbox installation (components: 1— gearbox viewing window sealing plate; 2— gearbox viewing window cork gasket; 3— oil baffle; 4— sealing partition; 5— upper internal spiral oil slinger; 6— upper external oil slinger; 7— driven gear shaft; 8— upper shaft end nut; 9— upper shaft sleeve; 10— test pinion; 11— test bearing clamp plate; 12— lower oil slinger; 13— test bearing bushing; 14— driving gear shaft; 15— lower shaft end nut; 16— test bearing; 17— test large gear; 18— gearbox viewing window glass; 19— air inlet pipe; 20— gearbox viewing window locking bolt; 21— bearing housing bracket; 22— bolt sleeve; 23— bolt; 24— lower bearing; 25— lower oil slinger bushing; 26— lower locking bushing; 27— lower internal spiral oil slinger; 28— lower bearing housing; 29— bearing housing washer; 30— upper bearing housing; 31— upper oil slinger bushing; 32— upper locking bushing; 33— upper bearing; 34— sealing paper gasket; 35— gearbox bracket; 36— gearbox body; 37— heater box; 38— exhaust pipe)

6. Recommended Operating Conditions

• Sample amount: 120 mL
• Sample temperature: 162.8℃±0.6℃
• Air box temperature: 171.1℃±2.8℃
• Heating time: within 55～60 min, raise to 162.8℃±0.6℃
• Air flow rate: 1.1 L/h (under pressure of 7 kPa)
• Load: 128 W
• Test time: continuous 50 h
• Air box temperature control adjustment: when the air temperature reaches 177℃, set the temperature controller to the control start position (6.5)
• Calibration of temperature recording and control instruments: accurately adjust the oil bath temperature to 163℃±0.5℃ (6.6)

7. Sampling and Sample Preparation

• 8.1 Add 120 mL of sample into the gearbox through the exhaust pipe. Turn the driving gear shaft four revolutions by hand to lubricate the test gears and bearings. Without heating, start the test machine for 5 min to further lubricate all parts. Then drain the sample from the gearbox until the sample flows out in drops, then drain for 5 min. Then add the weighed 120 mL of new sample into the gearbox.
• Preparation of the test gearbox (6.1): first clean the gearbox with solvent naphtha, then soak with cleaning agent for 4 h. After soaking, clean with a nylon brush and scouring cloth (during cleaning, take care to protect the surfaces of all components; do not use metal brushes or adherent cloths for scrubbing). Then rinse with water, remove water with ethanol, finally clean with toluene, and air dry.
• Preparation of test gears (6.2): polish all surfaces of the test gears with 360 water sandpaper. Carefully check the gear surfaces for scratches, marks, or defects. If any, polish with an oilstone, then clean with solvent, finally clean with toluene, and air dry.
• Preparation of test bearing (6.3): clean with solvent naphtha, finally clean with toluene, and air dry.
• Preparation of copper strip catalyst (6.4): for easy identification, file a notch on one side of a copper strip as a mark. Polish all surfaces of the two copper strip catalysts with 360 water sandpaper, clean and wipe with solvent naphtha and absorbent cotton, finally clean with toluene, and air dry. Before installation, weigh the marked copper strip catalyst (accurate to 0.1 mg). When handling the copper strip catalyst, use only tweezers or filter paper; do not touch directly with hands.

8. Analysis Procedure

• 8.2 Adjust the air flow rate to 1.1 L/h under a pressure of 7 kPa.
• 8.3 Start the test machine, turn on the heating switch, record the time, adjust the temperature so that the sample temperature rises to 162.8℃±0.6℃ within 55～60 min, adjust the generator voltage so that the output power is 128 W.
• 8.4 When the sample temperature reaches 162.8℃±0.6℃, record the test start time; at this time, the air box temperature should be 171.1℃±2.8℃.
• 8.5 The test runs continuously for 50 h. If the test is interrupted for more than 5 min, the test is invalid. If the test is interrupted within the last 2 h of 50 h, the test result is still valid.
• 8.6 After completing the 50 h operation, stop the machine, remove the air box cover, place the sample from the air inlet into a clean container within 5 min, weigh and record the weight of the discharged sample.
• 8.7 Remove the gearbox viewing window.
• 8.8 When disassembling the gearbox, do not damage the deposits on the components. Remove the copper strip catalyst, test gears, test bearing, and all components inside the gearbox.
• Installation of the test apparatus (Chapter 7):
  • 7.1 Installation of the test gearbox: according to Figure 2, install the components inside the gearbox in order from inside to outside: test bearing, test gears, copper strip catalyst, gearbox viewing window, sealing cork gasket and white paper gasket. Use new ones for each test.
  • 7.2 Installation of the test bearing: when installing the test bearing, face the side with the manufacturer's number outward. Tighten the bolts of the test bearing clamp so that the bearing runs freely.
  • 7.3 Installation of the test gears: when installing the test gears, face the side with the manufacturer's number outward. Tighten the shaft end nuts.
  • 7.4 Installation of the copper strip catalyst: install the copper strip catalyst holder, tighten the holder bolts, insert the copper strip catalyst into the slot of the clamp, and insert the marked copper strip catalyst on the inner side.
  • 7.5 Installation of the thermocouple: insert the thermocouple into the lower part of the gearbox, immerse it in the sample for 5 mm, and tighten the nut.
  • 7.6 Installation of the gearbox viewing window: apply a thin layer of vaseline on two new cork gaskets of 1.5 mm thickness and four paper gaskets of 0.125 mm thickness. Attach the paper gaskets to both sides of the cork gaskets, then sandwich the glass between the cork gaskets with attached paper gaskets. Then install the whole assembly onto the gearbox using the fixing plate, and tighten the bolts.
  • 7.7 Installation of the air thermocouple: install the thermocouple inside the air box cover, extending 75 mm below the cover plate, and tighten it.
  • 7.8 Installation of the exhaust pipe: install the exhaust pipe at the bottom of the gearbox and tighten the nut.
• Calibration of the test apparatus (Chapter 5):
  • 5.1 New test apparatus must be calibrated using two reference oils.
  • 5.2 After each year of use or after 20 tests, the test apparatus must be calibrated with two reference oils RGO-4668 and RGO-4669.
  • 5.3 After the test apparatus is moved or repaired with parts replaced, it must also be calibrated with two reference oils.
• Adjustment of air box temperature control (6.5): Before testing, the air box temperature control must be adjusted. First, install the air box cover with insulation layer on the test apparatus, insert the thermocouple to 75 mm below the top of the cover, connect the power to the heater and circulation fan, and when the air temperature reaches 177℃, adjust the temperature controller to the control start position. This adjustment is necessary during initial installation and should be checked periodically during testing to ensure consistency with the given temperature.
• Calibration of temperature recording and control instruments (6.6): Because this test is extremely sensitive to temperature, after installing a new test apparatus, all temperature control instruments and thermocouples must be calibrated with standard measuring instruments (and thereafter calibrated once a year). When calibrating thermocouples, immerse the thermocouple in a thermostatic oil bath with a stirrer, with an immersion depth of 20 mm, and accurately adjust the oil bath temperature to 163℃±0.5℃.

9. Qualitative and Quantitative Determination and Calculation Formulas

• 9.1 Clean the deposits on the marked copper strip with solvent naphtha, then rinse with toluene, air dry, and weigh (accurate to 0.1 mg). Report the copper strip weight loss expressed as %. The other copper strip does not need cleaning and remains as is.
• 9.2 Determine the 100℃ kinematic viscosity of the sample before and after the test. Unless otherwise specified, the sample is not filtered. The viscosity increase rate is expressed as %.
• 9.3 Determine the pentane insolubles of the sample after the test, expressed as %.
• 9.4 Determine the toluene insolubles of the sample after the test, expressed as %.
• 9.5 Determine the total acid number of the sample after the test, expressed as mgKOH/g.
• 9.6 Test weight loss: calculate the difference in test weight before and after the test, expressed as g.
• 9.7 Inspect and describe the condition of deposits on the surfaces of gears, bearings, and copper strips, and attach color photographs of the above test pieces.
  • 9.7.1 Colors are classified as: natural color, light brown, brown, dark brown, black.
  • 9.7.2 Hardness is classified as: very soft, soft, medium, hard, very hard.
  • 9.7.3 Thickness is expressed as μm.
  • 9.7.4 Types are classified as: lacquer film and sludge.
• Calculation formulas: not provided in the available source (only results are expressed as % or g, specific formulas are not given).

10. Precision

This standard has not yet established precision.

11. Report

• Fill in the evaluation results according to the vehicle gear oil thermal oxidation stability evaluation report format. See Appendix A (supplementary document).
• Appendix A Vehicle gear oil thermal oxidation stability evaluation report (L-60 method) (supplementary document):
  • Commissioning unit, sample name, commissioning date, viscosity grade, contact person, test number.
  • I. Test conditions (name | standard conditions | test conditions): sample temperature ℃ (162.8±0.6), heating temperature ℃ (171.1±2.8), heating time min (55～60), air flow rate L/h (1.1), load W (128), test time h (continuous 50).
  • II. Evaluation results (evaluation item | before test | after test | test result): copper strip catalyst weight loss g, sample weight loss g, total acid number mgKOH/g, viscosity increase rate %, pentane insolubles %, toluene insolubles %.
  • III. Description of test pieces after test (test piece name | description of test piece): copper strip (the face toward the gear is the front face) front/back; pinion gear (the face with the number facing outward is the front face) front/back/tooth surface; large gear (the face with the number facing outward is the front face) front/back/tooth surface; bearing (the face with the number facing outward is the front face) front/back/cage/balls.
  • IV. The temperature curve after the test and photographs of the test pieces are attached.
  • Evaluator, reviewer, group leader, director, year month day.

12. Referenced Documents

• GB 679 Ethanol
• GB 684 Toluene
• GB 1922 Solvent naphtha
• GB/T 7304 Determination of neutralization value of petroleum products and lubricants (potentiometric titration method)
• GB/T 8926 Determination of insolubles in used lubricating oils (B method)
• GB/T 11137 Determination of kinematic viscosity of dark petroleum products (reverse flow method) and calculation of dynamic viscosity
• SH/T 0039 Industrial petrolatum
• Editor's note (changes in referenced standards):
  • Original GB 697 → Current GB/T 697 Chemical reagent ethanol (95%)
  • Original GB 684 → Current GB/T 684 Chemical reagent toluene
  • Original GB/T 7304 → Current GB/T 731 day (requires confirmation against the source standard (source-text extraction), suspected to be GB/T 7304 corresponding to new number) Determination of acid value of petroleum products and lubricants (potentiometric titration method)

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