SH/T 0088-1991 Engine coolant simulated use corrosion determination 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

• Standard number: SH/T 0088-91
• Chinese name: Engine coolant simulated use corrosion determination method
• English name: not provided in the available source (the main text does not give an English name)
• Replacement relationship: not provided in the available source (the main text does not indicate a replaced standard)
• Other: the standard is marked "(2000 confirmed)"; by reference it adopts the American Society for Testing and Materials standard ASTM D2570-85 "Engine Coolant Simulated Use Corrosion Determination Method"
• Approval/implementation: approved by China Petrochemical Corporation 1991-11-26, implemented on 1992-12-01

2. Scope of application and non-applicability

• This standard specifies a method for evaluating, under laboratory constant-temperature conditions, the effect of engine coolant on metal test specimens and on the components of an automobile cooling system during circulation.
• This standard applies to engine coolant concentrate and engine coolant.
• Not applicable: not provided in the available source.

3. Method principle

The sample is circulated in a closed system consisting of a reservoir, water pump, radiator and rubber hoses at 88℃ and a certain flow rate for 1064h; its corrosion resistance is determined from the weight loss of typical metal test specimens used in engine cooling systems installed in the reservoir and by visual inspection of the condition of the inner surfaces of each component. The change in the performance of the sample is determined by analyzing samples taken from the system at regular intervals during the test period.

4. Reagents and materials (purity / preparation)

4.1 Reagents

• 5.1 Anhydrous sodium sulfate: chemically pure
• 5.2 Sodium chloride: chemically pure
• 5.3 Sodium bicarbonate: chemically pure
• 5.4 Hydrochloric acid: chemically pure (36%～38%)
• 5.5 Chromium trioxide: chemically pure
• 5.6 Phosphoric acid: chemically pure (85%)
• 5.7 Glacial acetic acid: chemically pure
• 5.8 Nitric acid: chemically pure
• 5.9 Acetone: chemically pure

4.2 Materials

• 4.2.1 Metal test specimens: shall meet the specification requirements in SH/T 0085. Solder test specimens may only be made by the method of brass plating with solder; because pure solder test specimens are easily bent and come into contact with adjacent specimens, they must not be used. Note: in addition to the test specimens specified in this standard, test specimens agreed upon by both the supplier and the purchaser are permitted.
• 4.2.2 Brass gaskets, insulating gaskets, insulating sleeves, brass wire brushes, soft brushes, emery cloth, sandpaper, metallographic sandpaper, brass scrapers, tweezers, etc.: the specification requirements are all given in SH/T 0085.
• 4.2.3 Brass screws: M6 × 65mm
• 4.2.4 Brass holder: dimensions are shown in Figure 3 (the figure is omitted in the source text)
• 4.2.5 Automobile cooling system cleaner

4.3 Preparation of corrosive water (7.1 Note ①)

Prepare by dissolving 148.g anhydrous sodium sulfate, 165.8 sodium chloride, and 138.g sodium bicarbonate in 1L distilled water or deionized water (doubt in the source text regarding the numerical units: the units after 148.g, 138.g, and 165.8 are missing, requires confirmation against the source standard (source-text extraction)).

5. Apparatus and equipment

• 4.1.1 Reservoir: see Figure 1, simulating an engine cylinder block, made of gray cast iron, composition: carbon 3.1%～3.4%, silicon 1.5%～2.0%, manganese 0.6%～0.9%
• 4.1.2 Automobile components: generally use the components of an ordinary automobile with a piston displacement of 1.6～5.0L, 4, 6 or 8 cylinders
  • a. Radiator: brass or aluminum
  • b. Radiator pressure cap: opening pressure is 80～103kPa
  • c. Water pump: aluminum or cast iron material
  • d. Rubber hoses: rubber hoses used in automobiles
  • e. Rubber hose clamps: worm-screw type is preferred
  • f. Observation tube: install a section of heat-resistant glass observation tube on the upper part of the radiator rubber hose to observe whether gas is present in the system; each end of the observation tube must have a slight flare
• 4.1.3 Pipe fittings: various pipe fittings connected by rubber hoses between the pump outlet and the reservoir inlet; malleable cast iron fittings are recommended, steel fittings may also be used
• 4.1.4 Motor: 1.1 kW or larger enclosed or explosion-proof motor
• 4.1.5 Pulley and belt: capable of driving the water pump to produce a flow rate of 1.3～1.6 L/s; the flow rate is measured by a flowmeter installed between the pump outlet and the reservoir inlet (as shown in Figure 2); the pressure drop between the pump outlet and the reservoir inlet is displayed by the pressure gauge in Figure 2; when a flowmeter is not used, the pressure drop may be maintained by adjusting the valve opening
• 4.1.6 Electric heater: about 2kW; an electric furnace may be installed under the reservoir or a heating band may be wrapped around the reservoir
• 4.1.7 Temperature controller: capable of maintaining the coolant temperature within the range of 88±3℃; the sensor is installed on the reservoir cover
• 4.1.8 Thermometer: capable of measuring coolant temperature, 30～100℃, with a scale division of 1℃, installed on the reservoir cover
• 4.1.9 Frame: use an appropriate structure to assemble all the accessories into a single unit

6. Recommended operating conditions

• 7.4.1 Coolant flow rate: maintain the coolant flow rate at 1.3～1.6 L/s
• 7.4.2 Temperature: except during shutdown periods, the test temperature is maintained at 88±3℃ from beginning to end
• 7.4.3 Test duration: the test runs 152h per week for a total of 7 weeks; except for two 8h shutdowns per week, the test shall be conducted continuously until 1064h is completed
• 8.3 Apparatus pressurization: the system pressure is raised to 80～103kPa, and this pressure is maintained while the apparatus is running; when the system is shut down, the air pressure must be released, and when it is started again, it must be repressurized

7. Sampling and sample preparation

7.1 Preparation of the sample

Mix the engine coolant concentrate with corrosive water at SH/T 0065 to prepare a sample with a freezing point of −29℃±1℃. If there are insoluble substances, they shall all be included in the sample so that it is representative. The corrosive water contains sulfate ions, chloride ions, and bicarbonate ions at 100ppm each. The freezing point is determined in accordance with SH/T 0090.

Note:

• ① Corrosive water is prepared by dissolving 148.g anhydrous sodium sulfate, 165.8 sodium chloride, and 138.g sodium bicarbonate in 1L distilled water or deionized water (doubt in the source text regarding the unit labeling, requires confirmation against the source standard (source-text extraction)).
• ② The engine coolant shall be added with the above three salts according to the proportion of water so that the concentrations of the above three ions in the water each reach 100ppm, and it shall be adjusted with corrosive water to prepare a sample with a freezing point of −29℃±1℃.

7.2 Preparation of test specimens

• 7.2.1 Drill a hole with a diameter of 7mm in the center of each metal test specimen so that it can be mounted on a brass screw with a length of 65mm and an outer diameter of 6mm and covered with a polytetrafluoroethylene tube.
• 7.2.2 Grind, clean, and weigh the test specimens in accordance with SH/T 0085.
• 7.2.3 Assembly of the test specimen bundle: assemble the test specimen bundle in accordance with Figure 3, and finally tighten the nut to ensure good contact.

7.3 Preparation of the apparatus

• 7.3.1 Before the test, remove rust and scale from the inner surfaces of the reservoir and cover by sandblasting or other methods, wash away fine sand particles with water and a brush, then blow dry with compressed air, and inspect the reservoir and cover; if relatively deep corrosion spots are found or leakage occurs, they must be replaced. Install a O type O-ring as a sealing ring between the reservoir and the cover, then tighten with screws, as shown in Figure 1.
• 7.3.2 New automobile components, namely the radiator, water pump, and connecting rubber hoses, must be used for each test. Note: if used components are cleaned by 7.3.4 and are proven to be usable, and the test does not require evaluation of the performance of each component, then in such cases the used components may be used. If necessary, they shall be cleaned in accordance with Appendix A, but new components must be used for arbitration tests.
• 7.3.3 Assembly of the apparatus: install each component in accordance with Figure 2, but do not install the metal test specimens.
• 7.3.4 Cleaning of the system
  • 7.3.4.1 Fill the system with tap water, add a certain amount of automobile cooling system cleaner, clean according to its instructions, and drain completely.
  • 7.3.4.2 Fill the system with tap water, start the water pump and heater, heat to 60～70℃, run for 15min, then shut down and drain completely.
  • 7.3.4.3 Fill the system again with tap water, start the pump and heater, run at 88±3℃ for 15min, then shut down, take 100mL of the tap water in the system, and then drain all the water from the system.
  • 7.3.4.4 If there is obvious sediment or foam in the tap water taken, repeat steps 7.3.4.2 and 7.3.4.3 until the water becomes clear and free of foam, then thoroughly drain all the water from the system.
• 7.3.5 Install three groups of test specimen bundles on the holder, with the center-to-center distance of each test specimen bundle being 65mm, fix the holder on top of the reservoir, tighten with screws, and install it into the reservoir, connecting it in the orientation shown in Figure 3.

8.5 Sampling and analysis

Test samples shall be taken at the beginning and end of the test. If necessary, samples may also be taken during the test in order to inspect and analyze coolant that has failed early and needs to be discarded immediately.

8. Analytical procedure

• 8.1 Start of test: pour the sample prepared in accordance with 7.1 into the system through the radiator filler opening. To leave room for coolant expansion, in general the sample is added to 40mm below the filler opening. Start the pump, check whether the coolant is circulating, and let it run safely for 5min. Remove excess entrained air by appropriate operations; if leakage is found, it must be repaired.
• 8.2 Pre-soaking the test specimens: shut down the system. With the sample not flowing and not heated, keep the test specimens stationary and pre-soak for 24h.
• 8.3 Pressurization of the apparatus: start the pump and heat so that the system temperature rises to the test temperature and the system pressure rises to 80～103kPa. This pressure must be maintained while the apparatus is running; when the system is shut down, the air pressure must be released. When it is started again, it must be repressurized.
• 8.4 Conducting the test: except for two 8h shutdowns per week, the test shall run continuously, with the interval between two shutdowns being about 3d; during shutdown, check the radiator liquid level. If the liquid level is low, replenish with a sample of the original coolant. Proceed in this manner, with a net operating time of 152h per week, until 1064h is completed.
• 8.5 Sampling and analysis: Test samples shall be taken at the beginning and end of the test. If necessary, samples may also be taken during the test in order to inspect and analyze coolant that has suffered early failure and must be discarded immediately. Observe the color, degree of turbidity, and the nature and amount of sediment, etc., of the samples taken. And according to SH/T 0069 and SH/T 0091, respectively determine the pH value and reserve alkalinity of the samples. When a sudden change occurs in the pH value and reserve alkalinity, the antifreeze concentration shall be measured.
• 8.6 End of test: Terminate the test when the test has been conducted for 1064h, and discharge the sample. If serious leakage or mechanical failure occurs, early shutdown is permitted.
• 8.7 Cleaning of test coupons: Immediately after shutdown, remove the metal test coupon bundle, and clean and weigh according to SH/T 0085.
• 8.8 Inspection of each component: Dismantle as soon as possible after the test is stopped, and inspect the inner surfaces of each component of the system. If leakage occurs in a certain component during the test, observe and determine the cause of leakage, and take appropriate measures.

Appendix A (Supplementary Document) Cleaning procedure for each component of the simulated service corrosion test that has been used or contaminated

• A1 Scope of application: This procedure is a supplement to 7.3.4. When the automotive components used in the test are seriously contaminated by oil-containing materials (such as contamination by oil-type corrosion inhibitors in the coolant), clean according to this procedure.
• A2.1 First sandblast the reservoir, then install the test system according to 7.3.3.
• A2.2 Fill the system with kerosene, operate for 1h at 50～60℃, then drain. Then fill the system with isopropanol, operate without heating for 15min, and drain. Then wash with water for 15min, and drain completely. Note: Isopropanol is extremely flammable, and its flash point is 13℃.
• A2.3 Continue washing with cleaning agent 7.3.4.1～7.3.4.4.

9. Qualitative and quantitative determination and calculation formulas

• Corrosion resistance is determined by the weight loss of typical metal test coupons used in the engine cooling system installed in the reservoir and by visual inspection of the inner surface condition of each component (Chapter 3).
• The corrosion mass loss of each test coupon shall be accurate to 1mg, and the average mass loss value of the test coupons after cleaning treatment shall be determined according to SH/T 0085, and the corrosion mass loss of each test coupon shall be corrected (10.1).
• Calculation formula: not provided in the available source.

10. Precision

The precision of this standard is temporarily not specified. When the corrosion mass loss value of each coupon is greater than 60mg, repeatability and reproducibility are usually very poor.

11. Report

• 10.1 The corrosion mass loss of each test coupon shall be accurate to 1mg, and the average mass loss value of the test coupons after cleaning treatment shall be determined according to SH/T 0085, and the corrosion mass loss of each test coupon shall be corrected.
• 10.2 Average mass loss of each type of test coupon.
• 10.3 Appearance of test coupons after washing: such as color, degree of brightness, corrosion condition, etc.
• 10.4 Appearance of the inner surfaces of the reservoir, coolant outlet, water pump, rubber hose, and radiator.
• 10.5 The pH value, reserve alkalinity, and appearance of the samples, and the antifreeze concentration in the samples collected at the beginning and end.
• 10.6 Detail the differences between the test conditions and procedures and this standard.
• 10.7 The characteristics of each automotive component used in the test, such as material, type, manufacturer part number, etc., their initial condition (new, old), and the cleaning procedure used.

12. Reference documents

• SH/T 0065 Sampling of engine coolant or rust inhibitor test samples and preparation of their aqueous solutions
• SH/T 0069 Determination of pH value of engine antifreeze, rust inhibitor, and coolant
• SH/T 0085 Determination of corrosion of engine coolant (glassware method)
• SH/T 0090 Determination of freezing point of engine coolant
• SH/T 0091 Determination of reserve alkalinity of engine coolant and rust inhibitor
• ASTM D2570-85 Determination of simulated service corrosion of engine coolant (referenced adoption)

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