Stainless steel pipes contain a large amount of chromium, and some also contain a large amount of nickel and a certain amount of titanium. The purpose of chromium is to make steel resistant to corrosion. Nickel is the main alloying element that forms austenitic stainless steel, but its full effect can only be exerted when combined with chromium. If pure nickel is used, low carbon nickel steel requires pure austenite single-phase structure and the nickel content needs to be above 24%. In fact, when the nickel content needs to reach 27%, the corrosion resistance of stainless steel pipes is significantly improved. , so there is no nickel as an alloying element in stainless steel pipes.
Common stainless steels are mostly austenitic stainless steels, such as 304, 316L, 321, etc. The carbon content is low, but the alloying element content is more than 20%, including 18-20% chromium, 8-10% Ni, and vanadium, molybdenum, titanium and other elements. Stainless steel is used for corrosive purposes. In the media, especially in industries such as food, medicine, daily chemicals and cosmetics that have higher environmental requirements, they are mostly used. Of course, it is also widely used in the chemical industry. However, austenitic stainless steel is afraid of chloride ions and has very strict control over chloride ions in water in the environment.
