NB/SH/T 0872-2013 Determination of shear stability of lubricating grease in the presence of water Water stability test

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Card type: Test method

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

• Standard number: NB/SH/T 0872—2013
• Chinese title: Determination of shear stability of lubricating grease in the presence of water Water stability test
• English title: Standard test method for determination of shear stabillity of lubricating grease in presence of water (water stability test) (thus in the source text, the spelling of stability is suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction))
• Method number: includes Method A (wet extended worked penetration test) and Method B (wet roll test)
• Replacement relationship: first release; modified adoption by redrafting method of ASTM D7342—2007
• Publication/implementation: published on 2013-06-08, implemented on 2013-10-01
• Issuing authority: National Energy Administration

2. Scope of application and non-applicability

• 1.1 specifies methods for determining the shear stability of lubricating grease in the presence of water, including two methods:
  • Method A—— wet extended worked penetration test, using a standard grease penetration worker, to determine the shear stability of lubricating grease under the condition of water presence.
  • Method B—— wet roll test, using roll stability test equipment, to determine the shear stability of lubricating grease under the condition of water presence.
• 1.2 uses [SI] International System of Units units; the values given in parentheses are for reference only.
• 1.3 involves certain hazardous materials, operations and equipment, but it is not intended to address all safety issues associated with them; users should establish appropriate safety and protective measures before use and determine applicable management systems.
• Non-applicability: no explicit non-applicability clause is provided in the available source.

3. Method principle

• 4 Method summary: under specified test conditions, a lubricating grease sample mixed with a small amount of water is worked in a standard grease worker (Method A) or roll stability worker (Method B) for a specified time and under specified conditions; the difference in penetration before and after working is used as the measured value of the wet shear stability of the lubricating grease.
• The source text also states: the two specified test procedures are widely used to determine the wet shear stability of lubricating grease in actual service; many lubricating grease specifications use these (wet) shear stability requirements (the source text here source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction)). In actual service, the test results and the wet shear stability of the lubricating grease do not have an exact correspondence.

4. Reagents and materials (purity / preparation)

• 7.1 Suitable volatile solvent (the specific type and purity are not provided in the available source)
• 7.2 Cloth or wiping paper: used for wiping; the cloth and wiping paper should be soft and must not leave scratches on the cone.
• 7.3 Distilled water: grade two water conforming to the provisions of GB/T 6682.
• Other purity and preparation details: not provided in the available source.

5. Apparatus and equipment

• 6.1 Grease worker: conforms to the provisions of GB/T 269.
• 6.2 Mechanical grease working apparatus (the source text contains Figure 1 Mechanical grease working apparatus).
• 6.3 Roll test machine: conforms to the provisions of SH/T 0122.
• 6.4 Cone: conforms to the provisions of GB/T 269.
• 6.5 Full-scale cone and rod for the corresponding grease worker, or 1/4 or 1/2 size cone and rod: as described in test methods GB/T 269.
• 6.6 Mixer: 500 r/min (the source text “500r/mic”, suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction)); and the mixing container in this chapter.
• Note: the correspondence between the numbers 6.1–6.6 and the content is organized according to the text of source-text extraction; some entries have incomplete text and require confirmation against the source standard (source-text extraction).

6. Recommended operating conditions

• Method A:
  • After mixing, let stand until the temperature reaches 25 ℃±0.5 ℃ (about 1.5 h).
  • Reciprocate 100 000 times (time about 28 h).
  • After working, let stand until the temperature reaches 25 ℃±0.5 ℃, then perform 60 reciprocating strokes (within 1 min).
• Method B:
  • The test time and indoor room temperature should be within 20 ℃–35 ℃; if the roll is in a closed chamber, the temperature inside the chamber should be maintained at 20 ℃–35 ℃.
  • After 120 min (the source text “after 120min”, the subsequent text is incomplete, requires confirmation against the source standard (source-text extraction)).
• Other conditions: not provided in the available source.

7. Sampling and specimen preparation

• Method A:
  • 8.1.1 Determine the worked penetration of the lubricating grease sample according to the provisions of GB/T 269, and record the measured value as P.
  • 8.1.2 Preparation of the sample and water mixture: place 450 g±1 g lubricating grease sample into a suitable mixing container (6.6), gradually add 50 g±1 g distilled water (7.3), and mix with a mixer or manually with a spatula until the sample is uniformly mixed.
  • The sample mixing process should be completed within 4 min±1 min; the uniform mixture after mixing should not show observable free water, otherwise (the source text is incomplete, requires confirmation against the source standard (source-text extraction)).
  • Use a spatula to transfer the uniform mixture of lubricating grease sample and water from the mixing container into the grease cup of the grease worker (6.1).
• Method B:
  • 8.2.1 Determine the 1/4 worked penetration of the lubricating grease sample according to the provisions of GB/T 269, and convert it to an approximate (full-scale) value according to the formula in GB/T 269 (the source text is incomplete), recording it as P.
  • 8.2.2 Use a spatula to evenly spread 63.0 g±0.2 g lubricating grease sample on the inner wall of the roll.
  • 8.2.3 Insert the (weighed) roller (the source text “5000g 50g”, suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction)).
  • 8.2.4 Add 7.0 g±0.2 g distilled water.
  • 8.2.5 Put on the cover and tighten it.
• Other sampling and preparation details: not provided in the available source.

8. Analytical procedure

• Method A (wet extended working test):
  • 8.1.1 Determine the worked penetration of the lubricating grease sample according to GB/T 269, and record it as P.
  • 8.1.2 Prepare a uniform mixture of sample and water according to Section 7, and transfer it into the grease cup of the grease worker.
  • 8.1.3 Install the grease worker containing the mixture in the mechanical grease working apparatus, and perform 100 000 reciprocating strokes as specified (time about 28 h); after working, remove the worker from the working apparatus and let stand until the temperature reaches 25 ℃±0.5 ℃ (about 1.5 h).
  • 8.1.4 When the uniform mixture of lubricating grease sample and water reaches 25 ℃±0.5 ℃, perform 60 reciprocating strokes (within 1 min), and determine the worked penetration of the uniform mixture according to the provisions of GB/T 269, recording the measured value as P (the recorded symbol is unclear in the source transcription; its interpretation as P remains unverified).
• Method B (wet roll test):
  • 8.2.1–8.2.5 see Section 7.
  • 8.2.6 Install the roll containing the lubricating grease sample and distilled water onto the roll test machine (6.3), start the instrument to begin rotation, and simultaneously record the time and indoor room temperature (20 ℃–35 ℃); if the roll is in a closed chamber, the temperature inside the chamber should be maintained at 20 ℃–35 ℃. After 120 min (the subsequent text is incomplete, requires confirmation against the source standard (source-text extraction)).
  • 8.2.7 Remove the roll from the roll test machine, unscrew the cover, take out the mixture sample of lubricating grease and water from the roll with a spatula, and then wipe the test equipment clean with a clean cloth or filter paper.
  • 8.2.8 Determine the worked penetration of the sample according to the provisions of GB/T 269; convert the measured value in 8.2.6 into an approximate full-scale penetration value, recording it as P.
• Other procedure details: not provided in the available source.

9. Qualitative and quantitative determination and calculation formula

• 9.1 Calculate the change in penetration of the sample according to the following formula:
  • Change in penetration = P − P₀ ………………(1)
  • Where:
    • P—— standard penetration value of the sample after test, 0.1 mm;
    • P₀——standard penetration value of the lubricating grease sample before test, 0.1 mm.
  • Note: the symbol source-text extraction in the source formula is incomplete; the above is organized according to context and requires confirmation against the source standard (source-text extraction).
• 9.2 A negative penetration value indicates that the lubricating grease sample becomes harder after the test, and a positive value indicates that the lubricating grease sample becomes softer after the test.

10. Precision

• 11.1 Precision: judge the reliability of test results according to the following provisions (95% confidence level).
  • 11.1.1 Repeatability: the difference between two consecutive test results obtained by the same operator using the same instrument under the same operating conditions on the same test sample should not exceed the value listed in Table 1.
  • 11.1.2 Reproducibility: the difference between two single independent results obtained by different operators in different laboratories on the same test sample should not exceed the value listed in Table 1.
• 11.2 Bias: there is a relatively large bias between Method A and Method B in this standard; although both methods can be used to determine the relative wet shear stability of lubricating grease samples, there is no correlation between the results determined by the two methods.
• Table 1 Repeatability and reproducibility provisions (unit: 0.1 mm):

11. Report

• 10 Report: The report on the wet shear stability of the grease sample shall include the following:
  • Change in penetration value;
  • The test method used;
  • Whether free water is present (when testing by method B).

12. Normative References

• GB/T 269 Standard test method for penetration of lubricating grease and petroleum grease (GB/T 269—1991, eqv ISO 2137:1985)
• GB/T 4016 Petroleum product terminology (one place in the source is written as "CB/T 4016", suspected to be source-text extraction noise, requires confirmation against the source standard (source-text extraction))
• GB/T 6682 Specifications and test methods for water for analytical laboratory use (GB/T 6682—1992, neg ISO 3696:1987) (the source text "neg" is suspected to be "neq", requires confirmation against the source standard (source-text extraction))
• SH/T 0122 Standard test method for roll stability of lubricating grease
• Terms and definitions reference: The terms and definitions defined in GB/T 269 and GB/T 4016, as well as the following terms and definitions, apply to this document.

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.

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