The ISO 9227-0 "Artificial Atmosphere Corrosion Test salt fog test" standard provides detailed methods and operating procedures for evaluating the corrosion resistance of metal materials. It covers three types of salt spray test: neutral salt spray test (NSS), acetic acid spray test (AASS) and CASS test (CASS) for testing the corrosion resistance of metals and their coatings. The standard is particularly suitable for rapid analysis of defects in coatings such as porosity and damage, but is not suitable for direct comparison of corrosion resistance between different materials. The standard specifies the test device, the method of use of reagents and the control requirements of the test environment.