SH/T 0123-1993 Determination of oxidation characteristics of extreme-pressure lubricating oils

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Card type: Test method

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

• Standard number: SH/T 0123-93 (confirmed in 2004)
• Chinese title: Determination of oxidation characteristics of extreme-pressure lubricating oils
• English title: not provided in the available source
• Replacement relationship: replaces SH/T 0123-92
• Reference adoption: ASTM D2893-88 "Determination of oxidation characteristics of extreme-pressure lubricating oils"
• First issued: 1985 year 3 month
• Approval/implementation: approved by China Petrochemical Corporation in 1993-06-11, implemented in 1994-05-01

2. Scope of application and non-applicability

• This standard specifies a method for determining the oxidation characteristics of extreme-pressure lubricating oils.
• It is applicable to extreme-pressure lubricating fluids such as gear oils.
• Note: The changes in lubricating oil measured according to this standard are not necessarily all related to oxidation of the lubricating oil; some changes may be caused by thermal degradation.
• For some new types of extreme-pressure lubricating oils, when this method cannot reasonably determine the quality of the oil, the determination may be carried out under 121℃.
• Not applicable: no explicit non-applicability clause is provided in the available source.

3. Method principle

The sample is subjected to 95℃, with dry air at constant pressure passed in, and tested for 312h; by measuring the increase in kinematic viscosity at 100℃ and the change in sediment value of the sample, the oxidation stability of the oil is expressed.

4. Reagents and materials (purity / preparation)

• 4.2.1 Air source: purified and dried.
• 4.2.2 Solvent naphtha: meets the specification requirements of SH 0004 or SH 0114.
• 4.2.3 Distilled water: meets the grade three water requirements in GB/T 6682.
• Air dryer packing: anhydrous calcium sulfate or a suitable desiccant; in areas with relatively high humidity, dehydrating agents such as sulfuric acid, sodium hydroxide, and silica gel should be added (4.1.5).
• Chromic acid cleaning solution: used to clean the oxidation tube, cover, and glass air delivery tube (5.1, 5.2).
• Purity/preparation details: not provided in the available source.

5. Apparatus and equipment

• 4.1.1 Oxidation tube: made of borosilicate glass, with a ground-glass stopper; the ground-glass stopper has a vent tube, and the tube diameter along the length direction is required to be uniform (see Figure 1).
• 4.1.2 Glass air delivery tube: as shown in Figure 2.
• 4.1.3 Heating bath: height 500mm±10mm, diameter 500mm±5mm, capable of accommodating at least 8 oxidation tubes, and capable of making the depth to which the oxidation tubes are immersed in the heating bath greater than 300mm; the constant-temperature control is required to maintain the oil temperature in the oxidation tubes at 95℃±0.2℃ or 121℃±0.2℃.
• 4.1.4 Flowmeter: float flowmeter, measuring range 0 to 200mL/min or 30 to 300mL/min, with a minimum division of 10mL/min.
• 4.1.5 Air dryer: the dryer is filled with anhydrous calcium sulfate or a suitable desiccant; before the air enters the flowmeter, it must be dried through the dryer (in areas with relatively high humidity, dehydrating agents such as sulfuric acid, sodium hydroxide, and silica gel should be added).
• 4.1.6 Thermometer: measuring range 0 to 100℃ and 100 to 200℃, with a division value of 0.2℃.

6. Recommended operating conditions

• Test temperature: 95℃; when new types of extreme-pressure lubricating oils cannot be reasonably determined, it may be carried out at 121℃.
• Test time: 312h.
• Air flow rate: 167mL/min±8.3mL/min (adjusted to stability within 30min).
• Air state: constant pressure, dry.
• Distance from the lower end of the glass air delivery tube to the bottom of the oxidation tube: 6mm±0.5mm.
• The oil level in the oxidation tube is at least 50mm below the liquid level of the heating bath.
• Heating bath temperature adjustment: after the oxidation tube containing cold oil is inserted into the heating bath, the temperature of the oil in the oxidation tube can reach the specified test temperature within 30min.
• During the test, adjust the heating bath temperature and air flow rate at any time, and record once every hour.

7. Sampling and sample preparation

• 6.2 Measure 300mL of sample and pour it into the test oxidation tube.
• Other sampling and sample preparation requirements: not provided in the available source.

8. Analytical procedure

• 5.1 Cleaning the oxidation tube: new oxidation tubes, covers, and glass air delivery tubes should be cleaned with chromic acid cleaning solution before each test, then rinsed with tap water, then washed three times with distilled water, and dried for later use.
• 5.2 Used oxidation tubes, covers, and glass air delivery tubes are first rinsed with solvent naphtha, then soaked in chromic acid cleaning solution for 12h, after pouring out, rinsed with tap water, scrubbed with a brush, rinsed clean with tap water, then rinsed three times with distilled water, and dried for later use. If used glass air delivery tubes still have sediment adhering to the wall that is difficult to remove after cleaning, they must no longer be used.
• 6.1 Adjust the temperature of the heating bath so that after the oxidation tube containing cold oil is inserted into the heating bath, the temperature of the oil in the oxidation tube can reach the specified test temperature within 30min.
• 6.2 Measure 300mL of sample and pour it into the test oxidation tube, then insert it into the heating bath that has reached the test temperature, so that the oil level in the oxidation tube is at least 50mm below the liquid level in the heating bath, then insert the glass air delivery tube into the oxidation tube, ensuring that the lower end of the glass air delivery tube is 6mm±0.5mm from the bottom of the oxidation tube.
• 6.3 Connect the glass air delivery tube, flowmeter, and air source, and adjust the air flow rate to reach 167mL/min±8.3mL/min (adjusted to stability within 30min). When the air flow rate becomes stable, check the temperature of the heating bath; when the bath temperature reaches the required temperature, record the test start time.
• 6.4 During the test, adjust the heating bath temperature and air flow rate at any time to achieve the specified ranges, and record once every hour.
• 6.5 After the test has proceeded for 312h, remove the oxidation tube from the heating bath and shake the sample in the tube thoroughly to mix. According to GB/T 265 and SH/T 0024, determine the 100℃ kinematic viscosity and sediment value of the sample before and after oxidation.

9. Qualitative and quantitative determination and calculation formulas

• 7.1 The increase in kinematic viscosity X₁ (%) is calculated according to formula (1): X₁ = (ν₂ − ν₁) / ν₁ Where: ν₁ — the 100℃ kinematic viscosity of the sample before oxidation, mm²/s; ν₂ — the 100℃ kinematic viscosity of the sample after oxidation, mm²/s.
• 7.2 The increase in sediment value X₂ (mL) is calculated according to formula (2): X₂ = B − A Where: A—— the sediment value of the sample before oxidation, mL; B—— the sediment value of the sample after oxidation, mL.

10. Precision

The following provisions are used to judge the reliability of test results (95% confidence level).

• 8.1 Viscosity increase value
  • 8.1.1 Repeatability: for the same operator, the difference between two repeated determination results shall not be greater than the maximum allowable repeatability difference shown in Figure 3.
  • 8.1.2 Reproducibility: for the same sample, the difference between two results determined by two laboratories shall not be greater than the maximum allowable reproducibility difference shown in Figure 3.
  • Note: This precision provision was established under the determination conditions of 95℃.
• 8.2 The precision of the sediment value increase is temporarily not specified.
• Specific values in Figure 3: not provided in the available source (source-text extraction does not give the data in the figure).

11. Report

• 9.1 Report the 100℃ kinematic viscosity increase of the sample (%), reported to one decimal place.
• 9.2 Report the sediment value increase of the sample (mL), reported to one decimal place.

12. Referenced documents

• GB/T 265 Petroleum products — Determination of kinematic viscosity and calculation of dynamic viscosity
• GB/T 6682 Water for analytical laboratory use — Specification and test methods
• SH 0004 Solvent naphtha for the rubber industry
• SH/T 0024 Determination of sediment value of lubricating oils
• SH 0114 Aviation washing gasoline
• ASTM D2893-88 Determination of oxidation characteristics of extreme-pressure lubricating oils (reference adoption)

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 questions and answers