SH/T 0331-1992 Lubricating grease corrosion test method

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

• Method number: SH/T 0331-92 (file name is SHT-0331-1992)
• Full name: Lubricating grease corrosion test method
• English name: not provided in the available source
• Replacement relationship: replaces SY 2710-66 (82)
• Other: confirmed in 2004; the standard body is marked "SH/T0331-1992 (2004)", and the page header is marked "SH/T 0331-92"

2. Scope of application and non-applicability

• Scope of application: This standard specifies the lubricating grease corrosion test method; it is applicable to determining the corrosiveness of lubricating grease to metals.
• Not applicable: not provided in the available source.

3. Method principle

The corrosiveness of lubricating grease to metals is determined by the color change that occurs after the surface of a metal test piece immersed in the lubricating grease is acted upon by the lubricating grease at a certain temperature for a certain period of time.

4. Reagents and materials (purity / preparation)

4.1 Reagents

• 3.1.1 95% ethanol: analytical reagent.
• 3.1.2 benzene: analytical reagent.
• Mixed solution for washing: 95% ethanol-benzene mixed solution (1:4) (see 6.4).

4.2 Materials

• 3.2.1 Sandpaper or abrasive cloth: grit size 180 or 220.
• 3.2.2 Absorbent cotton.
• 3.2.3 Metal piece: circular, diameter 38–40mm, thickness 3mm±1mm; or square, side length 48–50mm, thickness 3mm±1mm (the original text "thickness 3mm 1mm" is suspected to be ±1mm, requires confirmation against the source standard (source-text extraction)). The metal grade shall be determined according to the product standard of the sample. Each metal piece has one hole of diameter 5mm: for a circular metal piece, the center of the hole is located at a distance of 5mm from the edge; for a square metal piece, the center of the hole is located at a corner at a distance of 5mm from both sides.
• 3.2.4 Solvent naphtha for the rubber industry.
• Filter paper (see 6.2, 6.4).

5. Instruments and equipment

• 4.1 Beaker or porcelain cup: diameter not less than 70mm, height not less than 100mm.
• 4.2 Glass rod: about 20–30mm longer than the diameter of the beaker or porcelain cup, with two concave notches spaced 20–30mm apart, so as to hang small glass hooks.
• 4.3 L-shaped small glass hook: about 30mm long, used for hanging the metal piece.
• 4.4 Magnifying glass: capable of magnifying 6~8 times.
• 4.5 Porcelain evaporating dish or culture dish.
• 4.6 Steel needle or electric engraving machine.
• 4.7 Scraper.
• 4.8 Tweezers.
• 4.9 Constant-temperature oven: temperature can be controlled to 2° (original text as such, requires confirmation against the source standard (source-text extraction), suspected to be ±2℃).

6. Recommended operating conditions

• Test temperature: 100℃±2 (original text "100°C 2", requires confirmation against the source standard (source-text extraction)).
• Holding time: 3h.
• Sample layer requirement: the sample filled in the cup shall ensure that after the metal piece hung on the small glass hook is immersed, the sample layer is about 10mm higher than the metal piece.
• Number of metal pieces: two metal pieces of the same grade.

7. Sampling and sample preparation

• 6.1 Use a scraper to scrape off the surface layer of the sample. Then take approximately equal amounts of sample from at least three places not close to the container wall. Collect together not less than 200g of sample in a porcelain evaporating dish, carefully stir uniformly, and then transfer into a porcelain cup or beaker.
• 5.1 The entire surface of the metal piece shall be carefully polished longitudinally with sandpaper or abrasive cloth, and finally polished with 220 sandpaper or abrasive cloth until smooth and bright, with no obvious processing marks. The number of each metal piece may only be engraved on the side edge.
• 5.2 Hold the polished metal piece with tweezers in a porcelain evaporating dish or culture dish, wash it with benzene, then wipe it with absorbent cotton soaked in benzene, and finally dry it with dry cotton, and it must not come into contact with hands.
• 5.3 Observe the washed and dried metal piece with a magnifying glass; there must be no corrosion spots or other marks on it. For small pits and small spots on the metal piece, use a steel needle or electric engraving machine to scratch a circle with a diameter not exceeding 1mm (original text "Imm", requires confirmation against the source standard (source-text extraction)). If there are still stains on the metal piece, wash and dry it again; if corrosion marks still exist, the metal piece shall be discarded.

8. Analytical procedure

• 6.2 Hang two metal pieces of the same grade on the small glass hooks, then hang them at the notch of the glass rod in the center of the cup mouth, and lightly press the metal pieces with filter paper so that they are completely immersed in the sample. Care shall be taken not to let the metal pieces contact each other, not to let them contact the cup edge, and not to leave gaps.
• 6.3 Place the beaker containing the sample and metal pieces in a constant-temperature oven at 100℃±2, and maintain for 3h.
• 6.4 Exactly at 3h, take the metal pieces out of the cup, and transfer them in order into a porcelain evaporating dish. Use a glass rod and filter paper to carefully remove the sample adhering to the surface of the metal pieces. After removing the sample, carefully wash the metal pieces successively, first with solvent naphtha and then with 95% ethanol-benzene mixed solution (1:4). Then, rinse the metal pieces with 95% ethanol-benzene mixed solution, wipe dry with cotton or filter paper, and then observe carefully.

9. Qualitative and quantitative determination and calculation formula

• Judgment (7.1): Except for the places scratched by the steel needle or electric engraving machine and the places within 1mm from the hole and edge, if no spots and no obvious uneven color change are observed on the metal piece with the naked eye, the sample is considered qualified. When testing copper pieces and copper alloy pieces, slight uniform discoloration of the metal piece is allowed.
• Judgment (7.2): If corrosion marks are present on only one metal piece, the test shall be repeated. In the second test, even if the above corrosion situation appears again on one metal piece, the sample is considered unqualified.
• Calculation formula: not provided in the available source.

10. Precision

Not provided in the available source.

11. Report

Not provided in the available source.

12. Referenced documents

Not provided in the available source (the main text does not list a normative reference document list).

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