Test method for copper sheet corrosion of petroleum products

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The A2010 copper sheet corrosion tester produced by Delit (Beijing) Technology Co., Ltd. was developed in accordance with GB/T5096, and is suitable for determining the degree of corrosion of copper sheets caused by aviation gasoline, jet fuel, automotive gasoline, natural gas, other hydrocarbons with a vapor pressure at 37°C not exceeding 124 kPa (930 mm Hg), solvent oils, diesel fuel, distillate fuels, lubricating oils, and other petroleum products. Why is it necessary to measure copper sheet corrosion in petroleum products? Since crude oil contains acids, the vast majority of products derived from it are somewhat acidic (corrosive). Copper strip corrosion testing is used to measure the corrosiveness of petroleum products ； Different indicators are applicable to different levels of terminals. For example, liquefied gas is slightly corrosive to steel equipment and can dissolve rubber. Terminals for filling liquefied gas are equipped with plastic pipes; given its high corrosiveness, this definitely poses a hazard. Test method for copper strip corrosion testers: The copper strip corrosion testing equipment is used to determine the degree of corrosiveness of diesel, gasoline, lubricating oil, or other petroleum products on copper. This method involves flammable materials; therefore, prior to operation, it is necessary to pay attention to the ignition and flash points of the samples, and safety must be ensured during the process. Preparation for testing copper strip corrosion in petroleum products: 1. Clamp the copper strip longitudinally using a fixture. First, use relatively coarse sandpaper (the lower the grit number, the coarser the sandpaper) to remove any imperfections from the copper strip. The orientation of the copper strip within the fixture can be changed back and forth so that all imperfections and traces of previous grinding are removed from all six surfaces of the strip. After grinding, a quantity-controlled filter paper can be used to wipe off any metal particles from the surface of the copper strip. At this point, the copper strip may be placed in a cleaning solvent, dried, and then subjected to final polishing; alternatively, final polishing can be performed directly. The polished copper strips must be handled using tweezers or filter paper—direct hand contact is prohibited. 2. Use sandpaper with a higher grit number to sand the copper sheet, or use cotton swabs dipped in sand particles to polish the surface of the copper. When sanding, try to do so along the longitudinal axis of the copper sheet. 3. After polishing the copper sheet to a shine, use absorbent cotton to remove any metal debris. Once the copper sheet is clean, place it into the prepared sample. Test procedure for copper strip corrosion by petroleum products: 1. Sampling: Pour 30 milliliters of the sample into a test tube. The sample should be stored in a clean, dark-colored glass bottle whenever possible. The test tube must be dry and clean. 2. Different test procedures are used for different samples: A. For lubricating oils, solvent oils, and kerosene, take 30 milliliters of a completely clear sample free from suspended water or internal moisture, pour it into a clean, dry test tube equipped with a test tube holder. Place the freshly polished and clean copper sheet into the sample in the test tube, then place the test tube with its holder in a bath maintained at 100±1°C. After leaving it in the bath for 3±5 hours, remove the test tube and inspect the copper sheet. B. Aviation gasoline, jet fuel: Measure 30 ml of a completely clear sample with no suspended water or water content, and pour it into a clean, dry test tube. Carefully slide this test tube into the test bomb, tighten the bomb cap, and fully immerse the test bomb in a bath maintained at 100±1°C. After allowing it to remain in the bath for 2±5 hours, remove the test bomb, rinse it with tap water for several minutes, open the bomb, take out the test tube, and inspect the copper strip. C. Natural gasoline: Measure 30 ml of a completely clear sample with no suspended water or water content, and pour it into a clean, dry test tube. Carefully slide this test tube into the test bomb, tighten the bomb’s lid, and fully immerse the test bomb in a bath maintained at 40±1°C. After allowing it to remain in the bath for 2±5 hours, remove the test bomb, rinse it with tap water for several minutes, open the bomb, take out the test tube, and inspect the copper strip.

D. Diesel fuel, fuel oil, motor gasoline: Measure 30 ml of a completely clear sample with no suspended water or water content, and pour it into a clean, dry test tube equipped with a test tube holder. Place a polished, clean copper strip into the sample within the test tube. Then place the test tube with the holder into a bath maintained at 50±1°C. After leaving it in the bath for 3±5 hours, remove the test tube and inspect the copper strip.

Inspection of the copper strip:
1. Use tweezers to remove the copper strip. The sample can be washed off using cleaning solvent, or wiped away using filter paper; do not touch the copper strip with bare hands.
2. Place the copper strip into a flat observation tube to prevent any stains or contamination from occurring during inspection and comparison.
3. Compare the copper strip with the corrosion standard color chart. When making the comparison, hold both the copper strip and the color chart at a 45° angle relative to the light source for observation.
4. Determine the corrosiveness of the sample based on the grading indicated on the corrosion standard color chart