The testing standards for corrosion resistance of automotive parts mainly include the following:
**I. Salt spray test standards**
1. Neutral salt spray test (NSS): Such as international standard ISO 9227. Use sodium chloride brine with a concentration of 50g/L, and the pH value is between 6.5 – 7.5. Place the sample of automotive parts in a salt spray test chamber and continuously spray for a certain period of time. Observe the surface corrosion situation, including rusting, blistering, peeling, etc., to evaluate the corrosion resistance.
2. Acidic salt spray test (AASS): Add glacial acetic acid on the basis of the neutral salt spray test to reduce the pH value of the solution to 3.0 – 3.1. It is more corrosive and is used to simulate the corrosion resistance of automotive parts in harsh environments (such as acid rain areas).
3. Copper accelerated salt spray test (CASS): Add copper chloride on the basis of the acidic salt spray test to further enhance the corrosiveness of the salt spray. It can simulate the corrosion situation of automotive parts under extremely harsh conditions in a relatively short time. However, it is necessary to carefully select the test time and conditions to avoid excessive acceleration of corrosion and inability to truly reflect the actual usage situation.
**II. Cyclic corrosion test standards** Such as the ISO 11997 series of international standards, which stipulate different cyclic corrosion test methods, including cycles of multiple stages such as salt spray, drying, and wetting, to simulate various environmental conditions that automobiles may encounter in actual use, such as the alternating occurrence of humidity, drying, and salt spray. Through multiple cycle tests, the corrosion resistance of automotive parts in complex environments can be evaluated more comprehensively.
**III. Coating adhesion and corrosion resistance standards**
1. For automotive parts with coatings, such as paint, anti-corrosion coatings, etc., relevant coating adhesion and corrosion resistance standards need to be followed. For example, international standard ISO 2409 stipulates the test method for coating adhesion and evaluates the bonding force between the coating and the part substrate by means of grid cutting tests.
2. The ISO 4628 series of standards stipulates the evaluation method of corrosion grades such as blistering, rusting, and peeling of the coating to determine whether the corrosion resistance of the coating meets the requirements.
**IV. Material standards**
1. For the materials used in automotive parts, there are corresponding international standards to stipulate indicators such as chemical composition, mechanical properties, and corrosion resistance.
2. For example, for stainless steel materials, international standard ISO 15510 stipulates the chemical composition, mechanical properties, and corrosion resistance requirements of different grades of stainless steel.
3. For aluminum alloy materials, the ISO 6361 series of international standards stipulates the technical requirements and test methods for aluminum alloy sheets, profiles and other products, including the corrosion resistance test of materials.
