SH/T 0429-2007 Determination of compatibility of lubricating greases and liquid lubricants with rubber

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Card type: Test method

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

• Standard number: SH/T 0429—2007 (the original cover source-text extraction writes "SII/T 0429—.2007", requires confirmation against the source standard (source-text extraction))
• Chinese title: Determination of compatibility of lubricating greases and liquid lubricants with rubber
• English title: the original writes "Staedard test memod for d[garbled text]m[garbled text]of lebriaa[unreadable character]greases a[unreadable character]fltdds", source-text extraction is severely distorted, requires confirmation against the source standard (source-text extraction)
• Replacement relationship: replaces SH/T 0429—1992 "Determination of compatibility of lubricating greases with synthetic rubber"; SH/T 0429—1992 was formulated by reference to ASTM D4289—83
• Degree of consistency: the degree of consistency with the American Society for Testing and Materials standard ASTM D4289—03 "Determination of compatibility of lubricating greases and liquid lubricants with rubber" is non-equivalent
• Main changes compared with SH/T 0429—1992:
  • Modified the standard title, from "Determination of compatibility of lubricating greases with synthetic rubber" to "Determination of compatibility of lubricating greases and liquid lubricants with rubber"
  • Added content on the compatibility of liquid lubricants with rubber
  • Precision was modified according to ASTM D4289—03
  • Added Appendix A "Physical properties of standard rubber"
• Appendix A is a normative appendix
• Proposed by: China Petrochemical Corporation
• Administered by: Sinopec Research Institute of Petroleum Processing
• Drafted by: Chongqing Yiping Lubricant Branch of Sinopec Corp., Beijing Institute of Aeronautical Materials of China Aviation Industry Corporation I
• Main drafters: Xie Hong, Wang Jianshan
• Previous versions: SH/T 0429—1992

2. Scope of application and non-applicability

• 1.1 This standard specifies a method for determining the compatibility of lubricating greases and liquid lubricants with standard rubber test pieces. The standard rubbers are nitrile rubber (NBR—L) and neoprene rubber (CR).
• 1.2 It is applicable to the compatibility of lubricating greases and liquid lubricants with standard rubber test pieces, especially for the evaluation of the compatibility of automotive lubricating greases and liquid lubricants with rubber test pieces; it is also applicable to the evaluation of industrial liquid lubricants.
• 1.3 The test results are applicable to the evaluation of occasions where the mechanical requirements for rubber seals, sealing rings, O-type rings and similar products in contact with lubricating greases and liquid lubricants are not stringent. In applications where rubber parts in contact with lubricating greases and liquid lubricants face relatively large flexing, temperature and stress severity, other properties of the rubber, such as tensile strength and elongation at break, should be evaluated in order to more truly reflect their compatibility with rubber.
• 1.4 This standard involves certain hazardous materials, operations and equipment, but does not purport to address all safety problems associated with its use. Users should establish appropriate safety precautions and formulate corresponding management systems before using this standard.

3. Method principle

Place a standard rubber test piece of specified dimensions in a lubricating grease or liquid lubricant sample, and after testing at 100 ℃ (CR or similar rubber) or 150 ℃ (NBR—L) or other temperature required by the lubricant product specification for 70 h, evaluate the compatibility of the sample with rubber according to its volume change and hardness change.

4. Reagents and materials (purity / preparation)

• 5.1 Water: meets the requirements for grade three water in GB/T 6682.
• 5.2 Sodium dioctyl sulfosuccinate (wetting agent). Warning: handle with care. Avoid contact with eyes.
• 5.3 n-Heptane: chemically pure. Warning: flammable, harmful to health.
• 5.4 Anhydrous ethanol: chemically pure. Warning: flammable, harmful to health.
• 5.5 Standard rubber test piece: the rubber test piece meets the requirements of HB 5428 nitrile rubber (NBR—L) and neoprene rubber (CR); its physical properties are given in Appendix A. Test piece dimensions: a circular test piece with a diameter of 60 mm×2 mm or a rectangular test piece of 50 mm×25 mm×2 mm (the original source-text extraction writes "diameter is g(}mm×2mm [garbled specimen shape] or 50mm×25nun x 21[garbled text]-;35llll LI[unreadable character]35mh×2nmI rectangular specimen", the dimensional expression is distorted, requires confirmation against the source standard (source-text extraction)).
• 5.6 Qualitative filter paper.
• 5.7 Silk cloth (the original writes "[garbled silk-cloth name]", requires confirmation against the source standard (source-text extraction)).
• 5.8 One set of protective equipment (the original writes "[garbled protective-equipment name]_=j: one set", requires confirmation against the source standard (source-text extraction)).
• 6.3 Preparation of wetting agent solution: weigh 0.5 g sodium dioctyl sulfosuccinate, place it in 100 g water to dissolve, and prepare a sodium dioctyl sulfosuccinate wetting agent solution.

5. Apparatus and equipment

• 4.1 Shore A type durometer.
• 4.2 Balance: sensitivity 1 mg.
• 4.3 Heat-resistant glass beaker: low-form beaker, 100 mL, diameter about 50 mm, depth 70 mm, with volume graduation marks.
• 4.4 Watch glass: diameter about 60 mm.
• 4.5 Test piece hook: a stainless steel wire of a certain length with hooks at both ends, diameter about 0.5 mm, used for weighing test pieces.
• 4.6 Suspension wire: stainless steel wire with diameter 0.71 mm～0.72 mm, with structure as shown in Figure 1, so that the test piece is below the liquid surface.
• 4.7 Oven: air circulation type, temperature control accuracy ±2.5 ℃.

6. Recommended operating conditions

• Test temperature: 100 ℃ (CR or similar rubber) or 150 ℃ (NBR—L), or other temperature required by the lubricant product specification.
• Test time: 70 h±0.5 h.
• Oven temperature control accuracy: ±2.5 ℃.
• Cooling: after the test, the test piece is cooled in air to room temperature, cooling time about 30 min.
• Note (note to Chapter 10): Some lubricant specifications require different test conditions, such as extended time, lower or higher test temperature. In these cases, the repeatability and reproducibility values in Chapter 10 of this standard cannot be used, and the user and supplier should negotiate acceptable precision. The precision values apply to rubber that conforms to the physical characteristics of the standard rubber.

7. Sampling and test piece preparation

• 6.1 Wash the heat-resistant glass beaker and watch glass clean, dry them and place them in a dust-free place for later use (the original source-text extraction writes "dry and place in a dust-free location [garbled instruction]¨II", requires confirmation against the source standard (source-text extraction)).
• 6.2 Pour enough water into a 100 mL beaker and boil for about 5 min, cover with a watch glass, cool to 20 ℃～25 ℃ and set aside for use (the original source-text extraction writes "20％～25f.j[garbled temperature text]", the temperature expression is distorted, requires confirmation against the source standard (source-text extraction)).
• 7.1 Measure the initial hardness of the test piece H₁ on a Shore A type durometer in accordance with the provisions of GB/T 531.
• 7.2 Hang the test piece firmly with the hook and immerse it in water for 10 min～15 min, weigh accurately to 1 mg; the entire hanging part of the test piece hook should be completely immersed in water, and record the immersion depth. Mark a water level on the outside of the beaker so that the test piece is immersed in water at the same precisely measured depth.
• 7.3 Wipe off impurities on the surface of the test piece with a silk cloth dipped in n-heptane, and dry the test piece with cold air.
• 7.4 After the n-heptane has completely evaporated, weigh the total mass of the test piece hook and the test piece in air.
• 7.5 Use the test piece hook to immerse the test piece successively in the wetting agent solution and water, and after each immersion quickly lift the test piece so that the liquid drips off naturally.
• 7.6 Hang the test piece hook on the balance hook so that the test piece hook is immersed in water to the same depth as described in clause 7.2. Remove air bubbles adhering to the test piece; if the bubbles are difficult to remove, repeat the operation in clause 7.5; if they still cannot be removed, mechanically move the adsorbed bubbles.
• 7.7 Immerse the test piece in anhydrous ethanol, wash it clean, and then absorb the solvent on the test piece with filter paper.
• 7.8 For lubricating grease samples: apply about 10 mL of sample to the sides and bottom of the beaker, spread a thick layer of sample on the test piece with a spatula, place it in the beaker, spread sample around the test piece with a spatula, fill all gaps, and take care to eliminate air bubbles. When filled to about the 80 mL mark of the beaker (or about 80 g), and the test piece is completely covered by the sample, then level the sample surface with a spatula and cover with a watch glass. For liquid lubricants: fill the beaker to the 80 mL mark with the liquid lubricant sample, hang the test piece hook on the cover, place it in the beaker so that the test piece is completely immersed in the sample, and cover with a watch glass.
• 7.9 To ensure the volume ratio of rubber to sample, only one test piece is placed in one beaker, and two test pieces are used in one test.
• 7.10 Place the beaker containing the test piece in an oven preheated to 100 ℃±2.5 ℃ or 150 ℃±2.5 ℃ and keep it for 70 h±0.5 h. After the test, take the beaker out of the oven, remove the watch glass, take the test piece out of the beaker with tweezers and place it on the watch glass, cool to room temperature, cooling time about 30 min.
• 7.11 Scrape off the sample on the test piece with a spatula, then scrub the test piece with a silk cloth dipped in n-heptane, then immerse the test piece in anhydrous ethanol, wash it clean, and dry it with cold air or absorb it dry with filter paper.
• 7.12 Weigh the total mass of the test piece in air and water after the test respectively.
• 7.13 Measure the hardness of the test piece after the test H₂ on a Shore A type durometer in accordance with GB/T 531, and calculate the hardness change of the test piece ΔH according to clause 8.1.
• 7.14 Calculate the volume change of the test piece ΔV according to clause 8.2.

8. Analytical procedure

See Section 7 (original: "7 test procedure"). Sequence of key points: measure initial hardness → weigh in water (in air/in water) → rinse with n-heptane → soak with wetting agent → mount specimen (grease coating or liquid immersion) → oven 70 h → cool 30 min → clean → weigh after test → measure final hardness → calculate.

9. Qualitative and quantitative determination and calculation formulas

• 8.1 The change in specimen hardness is calculated according to formula (1):
  • ΔH = H₂ − H₁
  • Where: ΔH—— change in specimen hardness; H₁——initial hardness of the specimen, degrees; H₂——final hardness of the specimen, degrees.
  • Note: ΔH being a negative value means the specimen softened during the test, otherwise it hardened (original source-text extraction reads "}’::tj,, a negative value indicates softening during the test; otherwise hardening [garbled specimen/change wording]", requires confirmation against the source standard (source-text extraction)).
• 8.2 The change in specimen volume is calculated according to formula (2):
  • ΔV = (M₃ − M₄)(M₁ − M₂)/(M₁ − M₂)×100 (original source-text extraction reads "△V=.(M,[unreadable symbol]M;)(w—M2)/(M.[unreadable symbol]w,)×100", symbol subscripts are garbled, requires confirmation against the source standard (source-text extraction))
  • Where: ΔV—— change in specimen volume, %; M₁——after deducting the specimen hook, the mass of the specimen in air before the test, g; M₂——after deducting the specimen hook, the mass of the specimen in water before the test, g; M₃——after deducting the specimen hook, the mass of the specimen in air after the test, g; M₄——after deducting the specimen hook, the mass of the specimen in water after the test, g.
  • Note: If the initial density of the specimen is required, follow clause 8.3.
• 8.3 The specimen density may be calculated according to formula (3):
  • D = M₁/(M₁ − M₂)/d (original source-text extraction reads "D=M/fM,[unreadable symbol]M2)/dm", requires confirmation against the source standard (source-text extraction))
  • Where: D—— specimen density, g/cm³; M₁——after deducting the specimen hook, the mass of the specimen in air before the test, g; M₂——after deducting the specimen hook, the mass of the specimen in water before the test, g; d—— density of water, g/cm³.

10. Precision

Judge the reliability of the test results according to the following provisions (95% confidence level).

• 10.1 Repeatability: For repeated determinations by the same operator using the same instrument under the same operating conditions on the same sample, the difference between the two results obtained shall not exceed the value specified in Table 1.
• 10.2 Reproducibility: For determinations by different operators in different laboratories on the same sample, the difference between the two independent results obtained shall not exceed the value specified in Table 2.
• Note: The specifications for certain lubricants require different test conditions, such as extended time, lower or higher test temperature. In these cases, the repeatability and reproducibility values in Chapter 10 of this standard cannot be used. The user and supplier shall negotiate and determine acceptable precision. The precision values apply to rubber that conforms to the standard rubber physical properties.

Table 1 Repeatability

(original source-text extraction reads "ll 5" "1_5", requires confirmation against the source standard (source-text extraction))

Table 2 Reproducibility

(original Table 2 header source-text extraction reads "RBR—L", should be NBR—L, requires confirmation against the source standard (source-text extraction))

11. Report

• 9.1 The change in specimen hardness shall be the arithmetic mean of two repeated determination results, accurate to 0.5 degrees.
• 9.2 The percentage change in specimen volume: if ΔV≥10%, retain one decimal place; if ΔV<10%, retain two decimal places; take the arithmetic mean of two repeated determination results, and retain the result to two decimal places.

12. Referenced documents

• GB/T 531 Rubber pocket hardness tester indentation hardness test method (GB/T 531—1999, ISO 7619:1986, IDT)
• GB/T 6682 Specifications and test methods for water used in analytical laboratories (GB/T 6682—1992, ISO 3696:1987, NEQ)
• HB 5428 Vulcanized rubber sheets for testing low acrylonitrile butadiene rubber (NBR—L) and chloroprene rubber (CR)
• ASTM D4289—03 (degree of consistency is non-equivalent, see foreword)

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 for questions and answers