General stainless steel and acid-resistant stainless steel is a general term. Stainless steel is the resistance of air, steam and water corrosion of the steel medium weak, and acid-resistant steel refers to acid, alkali, salt, such as chemical erosion and corrosion of the steel medium. Stainless steel since the beginning of this century came, and now has 90 years of history. The invention of stainless steel is one of the world's major achievements in the history of metallurgy, stainless steel for the development of modern industrial development and progress of science and technology has laid an important material and technological foundation. Many kinds of stainless steel, different performance, which in the process of development has gradually developed a broad categories. According to the organizational structure of the sub-divided into stainless steel Markov (including precipitation hardening stainless steel), ferrite stainless steel, austenitic stainless steel and austenitic plus ferrite duplex stainless steel, and other four major categories; steel by the major chemical constituents or Some characteristics of the steel elements to the classification Cr divided into stainless steel, nickel chrome stainless steel, nickel chromium and molybdenum low-carbon stainless steel, high-Mo stainless steel, stainless steel, such as high purity; steel by the performance characteristics and uses, is divided into nitric acid-resistant stainless steel , Sulfuric acid-resistant stainless steel, pitting corrosion-resistant stainless steel, stress corrosion-resistant stainless steel, such as high-strength steel; steel according to the classification of features, the low temperature is divided into stainless steel, non-magnetic stainless steel, free cutting steel, stainless steel and so on superplasticity. The current classification method is commonly used by the steel structure and characteristics of the chemical composition of steel, as well as the characteristics of a combination of both methods of classification. Generally divided into martensite stainless steel, ferritic stainless steel, austenitic stainless steel, duplex stainless steel and precipitation-hardened stainless steel, or stainless steel and nickel-chromium is divided into two major categories of stainless steel.
     Stainless steel for the general anti-corrosive environment, as well as medical equipment and supplies.
     By major chemical composition of chromium into stainless steel, chrome and nickel chrome stainless steel stainless steel nitrogen, such as manganese; performance characteristics can be divided into acid-resistant stainless steel and heat-resistant stainless steel and so on; microstructure usually classified. Microstructure according to the classification as follows: Ferrite (F) stainless steel, martensite (M)-type stainless steel, austenite (A) type of stainless steel, austenite - ferrite (AF)-duplex stainless steel, Austria S body - martensite (AM)-duplex stainless steel and precipitation hardening (PH) stainless steel.