If you are engaged in the door and window industry, you will know, broken bridge aluminum doors and windows fastening screw of stainless steel used in the hardware system. There are 304 screws and 200 screws for stainless steel screw points. The content of nickel in 304 material is 8-10%, and the content of chromium reaches 18-20%. Such stainless steel will not rust under common circumstances. But 304 stainless steel will rust if the surrounding environment is too bad. At present, the so-called 200 series and 300 series stainless steel with high manganese content and low nickel content circulating in the market are not magnetic, but their performance is quite different from 304 with high nickel content. On the contrary, 304 has been stretched, annealing, polishing, casting and other processes will also be micro-magnetic, so it is a misunderstanding and unscientific to judge the advantages and disadvantages of stainless steel by using stainless steel band without magnetic. For example, 200 series of materials have excellent corrosion resistance in a dry and clean atmosphere, but if they are moved to coastal areas, flying needles will rust in sea fog containing a lot of salt. Therefore, not any kind of stainless steel can resist corrosion and rust at any time.
At present, there is a kind of 201 and 202 stainless steel in the market, which is easy to rust in coastal areas and is suitable for use in the environment without industrial pollution and air corrosion.
The coastal area should use 304 stainless steel, 304 material can resist seawater corrosion.
