About maintenance methods of 304 and 316 stainles steel,it's really diferent. In our daily production, we can use electroplating or oxidation-resistant metals to ensure the carbon steel surface, but this protection is only a film. If the protective layer is destroyed, the underlying steel begins to rust. The corrosion resistance of stainless steel depends on the chromium element. When the amount of chromium added reaches 10.5%, the atmospheric corrosion resistance of stainless steel will increase significantly, but if the chromium content is higher, although it can improve certain corrosion resistance. But not obvious. The reason is that this treatment changes the type of surface oxide to a surface oxide similar to that formed on pure chromium metal, but this oxide layer is very thin, and it can directly see the natural luster of the steel surface. To give stainless steel a unique surface. Moreover, if the surface is destroyed, the exposed steel surface will react with the atmosphere. This process is actually a self-repairing process, which re-forms the passivation film and can continue to protect.
Therefore, all stainless steels have a common characteristic, that is, the chromium content is above 10.5%, and the preferred steel grade also contains nickel, such as 304. The addition of molybdenum can further improve atmospheric corrosivity, especially against chloride-containing atmospheres, which is the case with 316.
In some industrial areas and coastal areas, the pollution is very serious, the surface will be dirty, and even rust has already occurred. However, if nickel-containing stainless steel is used, the aesthetic effect in an outdoor environment can be obtained. Therefore, our common curtain wall, side wall and roof are selected from 304 stainless steel, but in some aggressive industrial or marine atmospheres, 316 stainless steel is a good choice.