GB/T 512-1965 Determination of Water in 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: GB 512-65 (confirmed in the year 1982)
• Chinese name: Determination of Water in Lubricating Grease
• English name: Labricating grease—DetermInation of water (original text as such, suspected to be Lubricating grease—Determination of water, requires confirmation against the source standard (source-text extraction))
• Replacement relationship: From the date of implementation of this standard, the former Ministry of Petroleum Industry standard SYB 2704-59 "Determination of Water in Lubricating Grease" is void.
• Issued/implemented: Issued by the Standards Bureau of the State Scientific and Technological Commission 1965-01-20, implemented on 1965-10-01.

2. Scope of application and non-applicability

• Applicable to the determination of the water content of lubricating grease; the determination result is expressed as a weight percentage.
• Not applicable: not provided in the available source.

3. Method principle

A certain amount of sample is mixed with an anhydrous solvent, and its water content is determined by distillation and expressed as a weight percentage.

4. Reagents and materials (purity / preparation)

• 2.2.1 Pumice or unglazed ceramic pieces or glass capillaries closed at one end: must be dried before the test.
• 2.2.2 Solvent: straight-run gasoline with an initial boiling point not lower than 90 °C and a dry point not higher than 150 °C, which must be dried with anhydrous calcium chloride and filtered before use.
• 3.1 Oleic acid or stearic acid: third-grade purity.
• 3.2 Anhydrous calcium chloride: chemically pure.

5. Apparatus and equipment

• 2.1.1 Water determination apparatus: namely the apparatus of GB 260 "Determination of Water in Petroleum Products".
• 2.1.2 Scraper.
• 4.2 Straight condenser (the inner wall shall be wiped dry with cotton in advance).
• 4.3 Electric furnace or other heater.
• 4.4 Glass rod with rubber tip.
• Industrial balance (see 4.1).

6. Recommended operating conditions

• Heating: heat slowly with an electric furnace (or other heater).
• Reflux rate: after reflux begins, the condensate falling along the end of the condenser into the receiver shall be maintained at 2~4 drops per second.
• Distillation time: shall not exceed 1 hours.
• In arbitration tests, the difference between the cooling water temperature and room temperature shall be controlled within 5 °C (Note ②).
• The upper end of the condenser tube shall be plugged with cotton to prevent moisture in the atmosphere from condensing inside the condenser tube.

7. Sampling and sample preparation

• 4.1 Use a clean and dry scraper to scrape off the surface of the sample, take the sample from at least three places not close to the wall of the container, and weigh it after careful stirring.
• Sample amount: 20–25 grams, weighed to the nearest 0.1 grams; if the expected water content in the lubricating grease is above 10%, the sample weight shall be reduced to 10–15 grams (Note ①).

8. Analytical procedure

• 4.1 Weigh the sample into a pre-dried round-bottom flask, then inject 150 milliliters of solvent, and place several pieces of unglazed ceramic pieces, pumice, or several capillaries into the round-bottom flask.
• 4.2 Tightly assemble the round-bottom flask with the clean and dry receiver side tube, then connect the receiver to a straight condenser whose inner wall has been wiped dry with cotton in advance. During assembly, the beveled cut surface at the lower end of the condenser tube shall face the side tube opening of the receiver.
• 4.3 Heat slowly, controlling the reflux rate at 2~4 drops per second.
• 4.4 Near the end of the operation, if water droplets remain on the wall of the condenser, briefly increase the boiling intensity so that the condensed solvent washes the water droplets into the bottom of the receiver, or at the end of the operation scrape the water down with a glass rod with a rubber tip.
• 4.5 When the volume of water in the receiver no longer increases and the upper solvent layer has completely become transparent, stop the distillation. After the round-bottom flask has cooled slightly and the solvent and water in the receiver have reached room temperature, record the volume of water in the receiver.
• 4.6 If the solvent in the receiver becomes turbid, place the receiver in hot water for 20~30 minutes to clarify it and then cool it again.
• Note ③ During the test, if phenomena such as agglomeration, bumping, or emulsification and foaming occur and make the test impossible to carry out, it is permissible to add 5~10 grams of oleic acid or stearic acid. However, in this case, the sample shall be tested for free alkali according to SY 2707 (expressed as NaOH%), converted to the total alkali amount for the sample amount used for water determination, then multiplied by 0.45 as the correction value, and the correction value shall be subtracted from the water reading in the graduated tube. If the corrected value is negative, the water content of the sample is considered "none".

9. Qualitative and quantitative determination and calculation formula

• Calculation: The weight of water in the sample X (%) is calculated according to the following formula: X = V × 100 / G Where: V— is the volume of water in the receiver, milliliters; G— is the sample weight, grams.
• Note: The density of water at room temperature may be regarded as 1, so the number of milliliters of water is used as the number of grams of water.
• Judgment: If the amount of water in the receiver is less than 0.03 milliliters, it is considered a trace.

10. Precision

The difference between two repeated determination results shall not exceed one graduation above the portion occupied by water in the receiver.

11. Report

• Take the arithmetic mean of two repeated determination results as the water content of the sample.
• If the amount of water in the receiver is less than 0.03 milliliters, it is considered a trace.

12. Referenced documents

• GB 260 "Determination of Water in Petroleum Products"
• SY 2707 (determination of free alkali, expressed as NaOH%)
• SYB 2704-59 "Determination of Water in Lubricating Grease" (void)

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 reference