SH/T 0085-1991 Engine coolant corrosion determination method (glassware method)

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Card type: Test method

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

• Method number: SH/T 0085-91
• Chinese full name: Engine coolant corrosion determination method (glassware method)
• English name: not provided in the available source
• Replacement relationship: not provided in the available source
• Reference adoption: ASTM D 1384-87 "Test method for corrosion of engine coolant in glassware" (see additional notes)
• Approval/implementation: approved by China Petrochemical Corporation 1991-11-26, implemented on 1992-12-01

2. Scope of application and non-applicability

• Applicable to high-boiling-point and low-boiling-point engine coolants and their concentrates, and also applicable to engine cooling system rust inhibitors (Chapter 1).
• Not applicable: not provided in the available source.

3. Method principle

Six typical metals used in engine cooling systems are processed into test pieces, weighed, and connected into a test piece bundle, which is completely immersed in a sample with 750 mL and an air flow rate of 100±10 mL/min; high-boiling-point coolants and rust inhibitors are tested at 88±2 ℃, and low-boiling-point coolants at 71±2 ℃ for 336±2 h. After the test ends, the test pieces are removed, cleaned, and weighed again; corrosion is evaluated by the corrected mass change values of the test pieces before and after the test (Chapter 3).

4. Reagents and materials (purity / preparation)

4.1 Reagents (Chapter 5)

• 5.1 Hydrochloric acid: chemically pure [36%~38% (m/m)]
• 5.2 Chromium trioxide: chemically pure
• 5.3 Phosphoric acid: chemically pure (85%)
• 5.4 Glacial acetic acid: chemically pure
• 5.5 Anhydrous ethanol: chemically pure
• 5.6 Nitric acid: chemically pure
• 5.7 Anhydrous sodium sulfate: analytically pure
• 5.8 Sodium chloride: analytically pure
• 5.9 Sodium bicarbonate: analytically pure
• Note (original text): Hydrochloric acid, nitric acid, and phosphoric acid are strong acids; chromium trioxide is a highly toxic oxidant; glacial acetic acid is an organic acid with an irritating odor. Avoid contact with skin and eyes.

4.2 Materials (4.2)

• 4.2.1 Test pieces
  • 4.2.1.1 Steel test piece: meets the requirements of 20 quality carbon steel in GB 699, dimensions 50.0 mm×25.0 mm×2.0 mm, with a through hole of diameter 7.0 mm in the center.
  • 4.2.1.2 Brass test piece: meets the requirements of H70 copper in GB 5232, dimensions 50.0 mm×25.0 mm×2.0 mm, with a through hole of diameter 7.0 mm in the center.
  • 4.2.1.3 Copper test piece: meets the requirements of T2 copper in GB 5231, dimensions 50.0 mm×25.0 mm×2.0 mm, with a through hole of diameter 7.0 mm in the center.
  • 4.2.1.4 Cast iron test piece: chemical composition is carbon 3.0%~3.3%, silicon 1.8%~2.2%, manganese 0.6%~0.9%, phosphorus <0.3%, sulfur <0.12%, iron balance ("bowl" requires confirmation against the source standard (source-text extraction), should be sulfur); dimensions 50.0 mm×25.0 mm×3.5 mm, with a through hole of diameter 7.0 mm in the center.
  • 4.2.1.5 Solder test piece: the brass test piece described in 4.2.1.2 is coated with solder whose chemical composition is tin 29%~30%, lead balance. Coating the solder test piece or recoating a used test piece can be carried out by the method given in Appendix A. In addition, a solid test piece can also be made from solder. Dimensions 50.0 mm×25.0 mm×3.5 mm, with a through hole of diameter 7.0 mm in the center.
  • 4.2.1.6 Cast aluminum test piece: chemical composition is silicon 5.5%~6.5%, copper 3.0%~4.0%, iron <1.2%, manganese <0.8%, magnesium 0.1%~0.5%, nickel <0.5%, zinc <1.0%, titanium <0.25%, aluminum balance ("bowl" requires confirmation against the source standard (source-text extraction), should be titanium); dimensions 50.0 mm×25.0 mm×3.5 mm, with a through hole of diameter 7.0 mm in the center.
• 4.2.2 Washers
  • 4.2.2.1 Brass washer: outer diameter 12.0 mm, inner diameter 7.0 mm, thickness 4.5 mm.
  • 4.2.2.2 Insulating washer: made of polytetrafluoroethylene, outer diameter 12.0 mm, inner diameter 7.0 mm, thickness 4.5 mm.
  • 4.2.2.3 Steel washer: outer diameter 12.0 mm, inner diameter 7.0 mm, thickness 4.5 mm.
• 4.2.3 Brass screw: M4×60 mm.
• 4.2.4 Insulating sleeve: made of polytetrafluoroethylene, outer diameter 7.0 mm, thickness 1.9 mm.
• 4.2.5 Brass support: dimensions 50.0 mm×25.0 mm×2.0 mm, with a through hole of diameter 7.0 mm at a distance of 6.5 mm from the short side and 12.5 mm from the long side.
• 4.2.6 Brass wire brush
• 4.2.7 Soft-bristle brush
• 4.2.8 Emery cloth: grit 150
• 4.2.9 Sandpaper: grit 180, 240
• 4.2.10 Metallographic sandpaper: abrasive grit W20 (size range 20~14 μm)
• 4.2.11 Brass scraper
• 4.2.12 Tweezers ("forged" requires confirmation against the source standard (source-text extraction))
• 4.2.13 Air source: air supplied by an air compressor or a pipeline air source, capable of providing dry, clean air
• 4.2.14 Distilled water: meets the grade-three water requirements in GB 6682

4.3 Preparation of corrosive water (6.3.1)

Dissolve 148 mg anhydrous sodium sulfate, 165 mg sodium chloride, and 138 mg sodium bicarbonate in 1 L distilled water, so that the sodium salts of sulfate ions, chloride ions, and bicarbonate ions in the water are each 100 ppm. Note: If a large amount of corrosive water is needed for the test, 10 times the amount of the above three chemicals can be dissolved in 1 L distilled water to prepare a corrosive water concentrate; when needed, dilute 1 volumes of the concentrate with 9 volumes of distilled water.

4.4 Preparation of cleaning treatment solutions (7.5)

• 7.5.1 Copper and brass test pieces: 1:1 (by volume ratio) hydrochloric acid solution.
• 7.5.2 Cast aluminum test piece: 80 ℃ mixed solution of chromium trioxide and phosphoric acid; Note: dissolve 20 g chromium trioxide in 980 g 1:19 (by volume ratio) phosphoric acid solution ("81!19" requires confirmation against the source standard (source-text extraction)). If necessary, then soak in nitric acid for 1 min.
• 7.5.3 Solder test piece: boiling 1% (by volume ratio) glacial acetic acid solution.
• 7.5.4 Steel and cast iron test pieces: use a brass scraper and brass wire brush to remove adhering deposits, then scrub with a wet brush.

5. Instruments and equipment

• 4.1.1 Beaker: tall form, without spout, 1000 mL, made of heat-resistant glass.
• 4.1.2 Rubber stopper: fits tightly with the tall-form spoutless beaker, with through holes to accommodate the condenser, thermometer, and gas diffusion tube (test assembly shown in Figure 1).
• 4.1.3 Gas diffusion tube: the diffusion head is made of sintered glass, and the tube is made of heat-resistant glass (see Figure 2).
• 4.1.4 Thermometer: 30~100 ℃, scale division 1 ℃.
• 4.1.5 Reflux condenser: water-cooled type, jacket length not less than 400 mm.
• 4.1.6 Heater: electric heating plate or constant-temperature bath.
• 4.1.7 Air flow meter: float type or other type, flow range 0~200 mL/min.
• 4.1.8 Graduated cylinder: 1000 mL.
• 4.1.9 Balance: sensitivity 0.1 mg.
• 4.1.10 Desiccator.
• 4.1.11 Dewar flask: 1000, 5000 mL.
• 4.1.12 Cold trap.

6. Recommended operating conditions

• Sample volume: 750 mL (Chapter 3, 7.2)
• Air flow rate: 100±10 mL/min (Chapter 3, 7.3)
• Test temperature: high-boiling-point coolants and rust inhibitors 88±2 ℃; low-boiling-point coolants 71±2 ℃ (Chapter 3, 7.3)
• Test time: 336±2 h (Chapter 3, 7.3)
• Distance between the gas diffusion tube diffusion head and the test piece bundle: about 13 mm, to avoid the introduced air directly contacting the test piece bundle (7.2)
• Additional device for low-boiling-point coolants: the cold trap is immersed in industrial ethanol with dry ice, always maintained below -45 ℃ (7.4)
• During the test, frequently check the temperature, air flow rate, and liquid level; if the sample is insufficient due to evaporation, promptly replenish with distilled water (7.3)

7. Sampling and sample preparation

7.1 Sampling

Sampling of engine coolant or rust inhibitor samples shall be carried out in accordance with SH/T 0065 (6.2).

7.2 Test piece preparation (6.1)

• 6.1.1.1 The edges, four sides, and through hole of the test piece are polished with 150 grit emery cloth.
• 6.1.1.2 First, polish the six faces of the test specimen with sandpaper of grit 180, with the polishing direction parallel to the long edge of the specimen, until the surface has no pits, scratches, or rust. Then polish with sandpaper of grit 240, and finally polish with metallographic sandpaper.
• 6.1.1.3 After polishing, the test specimen must not be touched by hand again.
• 6.1.1.4 Clean the polished test specimen as soon as possible with anhydrous ethanol, and after drying, weigh to 0.1 mg. Note: If not used immediately, store the dried test specimen in a desiccator.

7.3 Test specimen bundle assembly (6.1.2)

First slip a polytetrafluoroethylene insulating sleeve onto the brass screw, then assemble the test specimens and washers in the following order: brass holder, insulating washer, copper test specimen, brass washer, solder test specimen, brass washer, brass test specimen, insulating washer, steel test specimen, steel washer, cast iron test specimen, steel washer, cast aluminum test specimen, insulating washer, brass holder. Tighten with a brass nut to ensure good electrical contact for each part of the test specimen bundle (see Figure 3). Note: With the agreement of both the supplier and the purchaser, multiple solder alloys may also be evaluated simultaneously, such as high-lead solder alloys containing 97% lead, ≤2.5% tin, and ≤0.30% silver (this sentence has severe noise in source-text extraction, requires confirmation against the source standard (source-text extraction)).

7.4 Test solution preparation (6.3)

• 6.3.2.1 Engine coolant concentrate sample: Use 6.3.1 corrosive water to prepare a sample with a freezing point of -18 ℃ (if the sample is an ethylene glycol type engine coolant concentrate, the volume ratio is 33.3%). The freezing point is determined using SH/T 0090.
• 6.3.2.2 Engine coolant sample: First use distilled water to prepare the sample into an aqueous solution with a freezing point of -18±1 ℃, then add appropriate amounts of anhydrous sodium sulfate, sodium chloride, and sodium bicarbonate so that the concentrations of these three chemicals in the sample are equivalent to those in the sample prepared in 6.3.2.1.
• 6.3.3 Rust inhibitor sample: Use 6.3.1 corrosive water to prepare a sample solution at the minimum use concentration recommended by the rust inhibitor manufacturer.

8. Analytical procedure

• 7.1 Thoroughly clean the beakers, rubber stoppers, thermometers, gas diffusion tubes, and reflux condensers used in the test.
• 7.2 For each sample, use three tall-form beakers, place one test specimen bundle in each beaker, and pour 750 mL of sample into each beaker. Assemble the rubber stopper, thermometer, gas diffusion tube, and reflux condenser as shown in Figure 1, keeping the gas diffusion tube head at a distance of about 13 mm from the test specimen bundle.
• 7.3 Place the assembled beaker on the heater, and connect the water, electrical, and gas lines. Conduct the test continuously for 336±2 h under the conditions in Section 6. During the test, frequently check the temperature, air flow rate, and liquid level; if the sample becomes insufficient due to evaporation, promptly replenish with distilled water.
• 7.4 Low-boiling-point engine coolants require an additional apparatus as shown in Figure 4, so that gas from the beaker passes through the reflux condenser and then through a cold trap. The cold trap is immersed in industrial ethanol with dry ice and is always maintained below -45 ℃. To maintain the liquid level in the beaker, promptly pour the condensate back into the respective beakers.
• 7.5 At the end of the test, immediately disassemble the test specimen bundle, gently brush with a soft-bristle brush and water to remove loosely adhering corrosion products. When more strongly adhering corrosion products and films are present on the test specimens, perform the following cleaning treatments respectively:
  • 7.5.1 Copper and brass test specimens: In a fume hood, immerse in 1:1 (volume ratio) hydrochloric acid solution for 15 s ("158" requires confirmation against the source standard (source-text extraction)), immediately rinse with tap water, and brush with a soft-bristle brush.
  • 7.5.2 Cast aluminum test specimens: In a fume hood, immerse in a mixed solution of 80 ℃ chromium trioxide and phosphoric acid for 5 min, immediately rinse with tap water, and gently brush with a soft-bristle brush to remove corrosion products and films. If film still remains, then immerse in nitric acid for 1 min, then rinse with tap water and brush with a soft-bristle brush.
  • 7.5.3 Solder test specimens: In a fume hood, immerse in boiling 1% (volume ratio) glacial acetic acid solution for 5 min, immediately rinse with tap water, and brush with a soft-bristle brush.
  • 7.5.4 Steel and cast iron test specimens: Use a brass scraper and brass wire brush to remove adhering deposits, then brush with a wet brush.
  • 7.5.5 After the various test specimens are cleaned according to 7.5.1~7.5.4, they must also be rinsed, first with tap water and then with anhydrous ethanol, and after drying, weighed to 0.1 mg. Test specimens that cannot be weighed immediately should be stored in a desiccator.
• 7.6 Determination of the average mass loss value for the cleaning treatment of test specimens:
  • 7.6.1 For each metal, take three untested test specimens that have been polished, rinsed with anhydrous ethanol, and dried, and weigh to 0.1 mg. Perform the cleaning treatments respectively according to 7.5.1~7.5.5, and after drying, weigh again to 0.1 mg. Take the average difference before and after the cleaning treatment of the three test specimens as the average mass loss value for the cleaning treatment of that metal test specimen.

9. Qualitative and quantitative and calculation formulas

• 8.1 Perform three tests for each sample, and record the corrected mass change value for each metal test specimen (mass before test minus mass after test minus average mass loss from cleaning treatment) to 1 mg.
• 8.2 Perform three tests for each sample, and record the arithmetic mean of the corrected mass change for the same metal test specimen to 1 mg.
• Note: A mass change value with a plus sign indicates a mass increase; a mass change value without a sign indicates a mass loss.
• Calculation formula: Not provided in the available source in formula form; only described in words as "mass before test minus mass after test minus average mass loss from cleaning treatment".

10. Precision

This standard is only a rough screening method for evaluating the corrosiveness of engine coolants and rust inhibitors, therefore there is no precision (Chapter 9).

11. Report

• 8.1 Perform three tests for each sample, and record the corrected mass change value for each metal test specimen (mass before test minus mass after test minus average mass loss from cleaning treatment) to 1 mg.
• 8.2 Perform three tests for each sample, and record the arithmetic mean of the corrected mass change for the same metal test specimen to 1 mg.
• Note: A mass change value with a plus sign indicates a mass increase; a mass change value without a sign indicates a mass loss.

12. Referenced documents

• GB 699 Quality carbon structural steel — Technical conditions
• GB 5231 Wrought copper — Chemical composition and product forms
• GB 5232 Wrought brass — Chemical composition and product forms
• GB 6682 Specifications for laboratory water
• SH/T 0090 Determination of freezing point of engine coolants
• SH/T 0065 Sampling of engine coolant or rust inhibitor test samples and preparation of their aqueous solutions
• Reference adoption: ASTM D 1384-87 "Test method for corrosion of engine coolants in glassware"

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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