SH/T 0804-2007 Detection of corrosive sulfur of insulating oils—Silver strip test

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. Standard designation, title, English title and supersession

• Standard designation: SH/T 0804—2007.
• Title translated from Chinese: Corrosive sulfur test for electrical insulating oils — silver strip method.
• English title in the source card: Detection of corrosive sulfur of insulating oils—Silver strip test.
• Supersession: not found; the available foreword information does not identify a superseded standard.
• Adoption relationship reported by the source card: modified adoption of DIN 51353—1985, corrosive sulfur testing of electrical insulating oils by the silver strip method; redrafted on the basis of DIN 51353—1985. This translation does not independently verify the foreword.
• Main technical differences from DIN 51353—1985, as reported from the foreword:
  • Some references use corresponding Chinese national standards.
  • DIN 51353—1985 specifies silicon carbide polishing material of grade P150 powder; this standard specifies silicon carbide abrasive paper of grade 150.
  • DIN 51353—1985 describes polishing a silver strip of width 20mm before making specimens of 20mm×40mm×0.5mm. This standard describes making specimens of 20mm×40mm×0.5mm first, then polishing them, with an additional procedure for polishing all edges.
• Publication and implementation: published on 2007-08-01; implemented on 2008-01-01.
• Institutional information in the source: proposed by China Petrochemical Corporation; technical responsibility assigned to Sinopec Research Institute of Petroleum Processing; drafted by the Karamay Lubricating Oil Research Institute of PetroChina Lubricant Company. Named drafters: Zhang Qi, Ma Shujie, Zhang Lingjun, Yu Huimin, Wang Peng, An Xiuling and Meng Yuchan. These names are transliterations of the source card.

2. Scope and exclusions

• 1.1 The standard specifies a test for corrosive sulfur in insulating oils that affects the operation of electrical equipment. This sentence is garbled in the source transcription and requires verification.
• 1.2 It applies to mineral insulating oils for electrical power equipment.
• Exclusions: not found in the available source.

3. Principle

• Keep a prepared silver strip in insulating oil at 100℃ for 18h, then examine its colour change to assess corrosion caused by sulfur and sulfides. The temperature is transcribed as 100 with an unclear unit, interpreted by the source card as 100℃; that interpretation remains unverified. The duration in this summary differs from the detailed procedure below; verify the original before setting the test duration.

4. Reagents and materials: purity and preparation

• 5.1 Acetone: analytical reagent, sulfur-free. The sulfur-free qualification is unclear in the source transcription and remains unverified.
• 5.2 Distilled water: meeting grade three requirements of GB/T 6682. The extracted designation CB/16682 is garbled and requires verification.
• 5.3 Chromic acid cleaning solution: the source card specifies approximately 50g K₂CrO₄, while the extracted formula reads K,Cr0, and remains unverified. Dissolve in 1L of sulfuric acid of at least 96% mass fraction, with density approximately 1.84 g/cm³; the source density unit p/cm' is also garbled and unverified. Store in a stoppered bottle. Verify the chemical identity and formula against the original before preparation; no correction to the formula has been inferred here.
• 5.4 Silver strips: 99.99% purity, 20mm×40mm×0.5mm, cold-rolled and uncontaminated.
• 5.5 Abrasive: silicon carbide paper of grade 150 meeting GB/T 2480.
• 5.6 Absorbent cotton: medical absorbent cotton; the material name is unclear in the source transcription and remains unverified.
• 5.7 Filter paper: quantitative analytical filter paper; this qualification is unclear in the source transcription and remains unverified.
• 5.8 Detergent: laundry powder or another detergent.

5. Apparatus

• 4.1 Oven: controlled at 100℃±2℃, preferably a forced-air constant-temperature oven. The extracted temperature specification reads 100C*2 with an unclear final unit; verify the temperature and tolerance against the original.
• 4.2 Flask: a 100mL ground-glass conical flask with glass stopper, made from chemically resistant glass; for example, a conical flask with standard ground joint φ29/32mm and matching stopper.
• 4.3 Tweezers: stainless steel, with flat tips.

6. Recommended operating conditions

• Test temperature: 100℃±2℃ in the oven; the source transcription of the temperature specification remains unverified.
• Test duration: 18h 30min (8.2). The principle summary gives a different duration; verify the original before setting the test.
• Drying: dry washed flasks in an oven at 105℃ (7.1); dry silver strips at 100℃±2℃ for 1min (7.2.4). The oven temperature transcription remains unverified.
• Strip angle: bend into a V with an included angle of 60°.
• Viewing: examine in daylight with the strip surface at 45° to the light to avoid glare.

7. Sampling and sample preparation

• 6 Sampling: sample according to GB 7597. The extracted designation (B 7597 is garbled and requires verification.
• 8.1 Do not filter the sample.
• 7.1 Cleaning flasks: remove oil with detergent, rinse with tap water, wash with the specified chromic acid solution, then rinse with tap water until no acid remains. Rinse three times with distilled water and dry in an oven at 105℃. Clean stoppers in the same way. The cleaning-solution chemical identity remains unverified as noted above.
• 7.2 Preparation of silver strips:
  • 7.2.1 Before testing, manually polish a strip of 20mm×40mm×0.5mm. Apply light pressure through absorbent cotton and rub grade 150 silicon carbide paper along the longitudinal axis, not in circles. Polish all edges in the same way. Place filter paper under the strip to avoid direct contact with hands or the bench.
  • 7.2.2 After polishing both faces, wipe the strip with silk to remove abrasive and metal dust. Continue with the following preparation and begin the test immediately afterwards.
  • 7.2.3 Bend the strip into a V with an included angle of 60°; do not touch it directly by hand.
  • 7.2.4 Clean the strip twice using absorbent cotton moistened with acetone, then immediately place it with the V apex upward in an oven at 100℃±2℃ for 1min, on filter paper. The source oven-temperature transcription remains unverified.

8. Procedure

• 8.1 Do not filter the sample. Add 100mL to a flask cleaned according to 7.1. Using clean tweezers, place the strip prepared according to 7.2 at the bottom with its V apex upward. Lubricate the stopper with a little test oil and insert it without tightening.
• 8.2 Place the flask in an oven at 100℃±2℃ for 18h 30min. The principle summary gives a different duration, and the oven-temperature transcription is unclear; verify both against the original before use.
• 8.3 At the end of the test, remove the strip with tweezers and wash off the oil thoroughly with acetone. Examine in daylight at an angle of 45° between the strip surface and the light to avoid glare. Compare with a newly prepared strip to assess discolouration. The source transcription of the strip reference in this sentence is unclear and remains unverified.

9. Identification, quantification and calculations

• 9 Interpretation: determine whether corrosive sulfur is present using Table 1.

Table 1: criteria for the presence or absence of corrosive sulfur

• Calculation formula: none found; this is a qualitative assessment and the source card gives no calculation formula.

10. Precision

• Not found in the available source.

11. Reporting

• 10 Report the sample as containing or not containing corrosive sulfur according to Table 1.

12. Referenced documents

• GB/T 2480: conventional abrasives — silicon carbide. The extracted designation CB/T2480 is garbled and requires verification.
• GB/T 6682: water for analytical laboratory use — specification and test methods (GB/T 6682—1992, neq ISO 3696:1987, as stated in the source card). The extracted designation CB/T 6682 is garbled and requires verification.
• GB 7597: sampling of insulating oils and turbine oils for electrical power equipment. The extracted designation CB 7597 is garbled and requires verification.

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