SH/T 0596-1994 Determination of contact resistance of lubricating grease

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 name / English name / replacement relationship

• Standard number: SH/T 0596-94
• Full name: Determination of contact resistance of lubricating grease
• English name: not provided in the available source
• Replacement relationship: not provided in the available source
• Approval/implementation: approved by China Petrochemical Corporation 1994-05-04, implemented on 1994-12-01

2. Scope of application and non-applicability

• This standard specifies the test method for contact resistance of lubricating grease.
• This standard is applicable to the determination of the contact resistance of lubricating grease.
• Not applicable: not provided in the available source.

3. Method principle

Apply the lubricating grease sample onto the plate electrode with a grease coating thickness of 0.2 (unit not provided in the available source, suspected to be mm, requires confirmation against the source standard (source-text extraction)), bring it into contact with the hemispherical electrode, and ensure that the force of 1.38N±0.01N is borne between the two electrodes. Use a DC double-arm bridge to measure the contact resistance at high temperature (50℃±1℃), room temperature (15～30℃), and low temperature (−25℃±2℃), and take the difference between the contact resistance before and after grease coating as the contact resistance value of the lubricating grease.

4. Reagents and materials (purity / preparation)

• 3.1 Hemispherical and plate electrodes, see Figure 1 (electrode shape).
• 3.2 901 metallographic abrasive paper and 600 water abrasive paper (the source text reads “901) metallographic abrasive paper and 60() water abrasive paper”, requires confirmation against the source standard (source-text extraction)).
• 4.5 Weight: 100g.
• Absorbent cotton (see 5.1).
• Lubricating grease sample to be tested.
• Purity, preparation: not provided in the available source.

5. Instruments and equipment

• 4.1 Lubricating grease contact resistance tester: see Figure 2 and Figure 3.
• 4.2 DC double-arm bridge: measurement range 0.0001～1Ω (the source text reads “0.0001[unreadable separator]len”, requires confirmation against the source standard (source-text extraction)), sensitivity not lower than 0.01Ω (the source text reads “0.01r Qo”, requires confirmation against the source standard (source-text extraction)).
• 4.3 Refrigerating apparatus: the refrigerating temperature should be lower than −30℃, and the volume of its cold chamber should be greater than diameter 45mm and height 90mm.
• 4.4 Constant-temperature water bath: constant temperature at any temperature between 30～80℃, with an error of ±1℃ (the source text reads “[unreadable sign]loco”, requires confirmation against the source standard (source-text extraction)).
• 4.5 Weight: 100g.
• Figure 2 Components of the lubricating grease contact resistance tester (room temperature): 1— tray; 2— nylon connecting rod; 3— connecting rod fixing part; 4— electrode wiring bolt; 5— brass connecting rod; 6— bolt for fixing the electrode; 7— hemispherical electrode; 8— plate electrode; 9— electrode wiring bolt; 10— anchor bolt; 11— instrument base plate; 12— anchor bolt; 13— support column; 14— connecting rod.
• Figure 3 Components of the lubricating grease contact resistance tester (50℃, −25℃): 1— aluminum cover; 2— test cup; 3— electrode connecting bolt; 4— connecting rod; 5— electrode wiring bolt; 6— plate electrode insert; 7— connecting rod.

6. Recommended operating conditions

• Room-temperature measurement temperature: 15～30℃.
• High-temperature measurement temperature: 50℃±1℃, constant temperature in a constant-temperature water bath 30min.
• Low-temperature measurement temperature: −25℃±2℃, constant temperature in a refrigerating apparatus 30min.
• Force borne between electrodes: 1.38N±0.01N (including the weight 100g and the total mass of the tray, connecting rod, hemispherical electrode, and bolt being 140g±1g).
• Bridge connection: connect to the electrodes by the double-wire connection method, see Figure 4.

7. Sampling and sample preparation

• 5.1 Polish the electrodes clean with metallographic abrasive paper so that they show a uniform, bright metallic luster, and wipe off copper chips with absorbent cotton. The treated electrodes should not come into contact with hands or unclean objects, and tweezers should be used when assembling the electrodes.
• 5.2 Polish clean with water abrasive paper the contact points such as terminals and cable lugs on instruments and equipment, and ensure good contact.
• 5.3 Connect the bridge to the electrodes by the double-wire connection method, see Figure 4.
• 6.1.6 Evenly apply the lubricating grease sample to be tested into the groove of the plate electrode, and level it with a scraper.
• Sampling amount, sample pretreatment: not provided in the available source.

8. Analytical procedure

6.1 Determination of contact resistance at room temperature

• 6.1.1 Install the treated electrodes in the tester, and connect to the bridge according to clause 5.3.
• 6.1.2 Control room temperature between 15～30℃.
• 6.1.3 Bring the hemispherical electrode into contact with the plate electrode so that it bears (including the weight 100g and the total mass of the tray, connecting rod, hemispherical electrode, and bolt being 140g±1g) a force of 1.38N±0.01N, read 5 values on the bridge, and take their average as the contact resistance value of the 1th point.
• 6.1.4 Move the plate electrode, change the position of the hemispherical electrode on the plate electrode, and repeat step 6.1.3 to measure the contact resistance values of the 2th and 3rd points. Take the average of the contact resistances of the three points as the blank value.
• 6.1.5 In the blank value test, the maximum deviation between the 5 readings at each point and their arithmetic mean should not exceed 0.03mΩ (the source text reads “0.03mn”, requires confirmation against the source standard (source-text extraction)). The maximum deviation of the resistance values of the three points should not exceed 0.05mΩ of their arithmetic mean (the source text reads “0.05mn”, requires confirmation against the source standard (source-text extraction)). Otherwise, the determination should be repeated.
• 6.1.6 Evenly apply the lubricating grease sample to be tested into the groove of the plate electrode, and level it with a scraper. Determine the contact resistance value after grease coating according to 6.1.3 and 6.1.4.

6.2 Determination of contact resistance at high temperature

• 6.2.1 Place the test apparatus shown in Figure 3 in a constant-temperature water bath already adjusted to the test temperature 50℃±1℃, and keep at constant temperature for 30min.
• 6.2.2 Referring to 6.1.3 and 6.1.4, determine the blank value of contact resistance at high temperature; for the deviation of the measured data, refer to 6.1.5.
• 6.2.3 Referring to 6.1.6, determine the contact resistance after grease coating; for the deviation of the measured data, refer to 6.1.5.

6.3 Determination of contact resistance at low temperature

• 6.3.1 Place the test apparatus shown in Figure 3 in a refrigerating apparatus adjusted to the test temperature −25℃±2℃ and keep at constant temperature for 30min.
• 6.3.2 Referring to 6.1.3 and 6.1.4, determine the blank value of contact resistance at low temperature; for the measured data, refer to 6.1.5.
• 6.3.3 Referring to 6.1.6, determine the contact resistance after grease coating; for the deviation of the measured data, refer to 6.1.5.

9. Qualitative and quantitative determination and calculation formula

• 7 Calculation: R = R₂ − R₁
  • R: lubricating grease contact resistance value, mΩ;
  • R₁: average contact resistance without grease coating, i.e. blank value, mΩ;
  • R₂: average contact resistance after grease coating, mΩ.
• 8 Report: take the arithmetic mean of 3 contact resistance measurement values as the determination result, with the number accurate to 0.01mΩ.

10. Precision

• In the blank value test, the maximum deviation between the 5 readings at each point and their arithmetic mean should not exceed 0.03mΩ (the source text reads “0.03mn”, requires confirmation against the source standard (source-text extraction)).
• The maximum deviation of the resistance values of the three points should not exceed 0.05mΩ of their arithmetic mean (the source text reads “0.05mn”, requires confirmation against the source standard (source-text extraction)).
• Repeatability, reproducibility: not provided in the available source.

11. Report

Take the arithmetic mean of 3 contact resistance measurement values as the determination result, with the number accurate to 0.01mΩ.

12. Referenced documents

Not provided in the available source.

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