Salt spray test chamber is an environmental test which mainly uses the artificial simulated salt spray environment conditions created by salt spray test equipment to evaluate the corrosion resistance of products or metal materials.It is divided into two categories, one is natural environmental exposure test, the other is artificial accelerated simulated salt spray environmental test.Artificial simulation of salt fog environment test is to use a certain volume space of the test equipment - salt fog test box, in the volume space of the artificial method, to create a salt fog environment to evaluate the product's salt fog corrosion performance and quality.Compared with the natural environment, the salt concentration of chloride in the salt fog environment can be several times or dozens of times higher than that in the general natural environment, which greatly improves the corrosion rate and shortens the time of the salt fog test.If a product sample is tested in a natural exposure environment, the corrosion may take a year, but in a simulated salt spray environment, similar results can be obtained in 24 hours.
The simulated salt spray test includes neutral salt spray test, acetate spray test, copper salt accelerated acetate spray test and alternating salt spray test.
1. The neutral salt spray test (NSS test) is a kind of accelerated corrosion test method that appears early and is widely used at present.It uses a 5% sodium chloride brine solution with a PH in the neutral range (6 ~ 7) as a spray solution.The test temperature was 35℃, and the settlement rate of salt spray was required to be between 1 ~ 2ml/80cm. H.
2. The acetate spray test (ASS test) is developed on the basis of the neutral salt spray test.It is in 5% sodium chloride solution to add some glacial acetic acid, make the PH value of the solution down to 3 or so, the solution becomes acidic, * after the formation of the salt spray is also from neutral salt spray into acid.It corrodes about three times faster than NSS.
3. Copper salt accelerated acetate fog test (CASS test) is a newly developed salt fog corrosion test in foreign countries. The test temperature is 50℃.Its corrosion rate is approximately 8 times that of the NSS test.
4. The alternating salt spray test is a comprehensive salt spray test, which is actually a neutral salt spray test and a constant humidity and heat test.It is mainly used for cavity type complete machine products, through the penetration of tidal environment, salt spray corrosion not only on the surface of the product, but also in the product.It is the product in the salt spray and hot and humid two environmental conditions under the alternating conversion, * after the examination of the electrical and mechanical properties of the whole machine products have not changed.