321 stainless steel seamless round pipe belongs to metal composite material. Stainless steel refers to the steel resistant to the corrosion of weak corrosive media such as gas, steam and water and organic chemical corrosive media such as acid, alkali and salt. It is also called stainless steel acid resistant steel. In practical application, the steel resistant to the corrosion of weak corrosive media is often called stainless steel, The steel resistant to solvent medium erosion is called acid resistant steel. Due to the difference in composition between the two, the former one is not resistant to solvent medium erosion, and the latter one is generally stainless steel.

The corrosion resistance of stainless steel lies in the aluminum alloy elements contained in the steel. The aluminum alloy elements of stainless steel cornerstone also include nickel, molybdenum, titanium, niobium, copper and nitrogen, so as to meet the regulations on the mechanism and function of stainless steel for various main purposes. Stainless steel is casually eroded by the content of chloride ion. Because chromium, nickel and chlorine are homologous elements, The homologous elements will exchange and assimilate, resulting in the corrosion of stainless steel. \ x0d the corrosion resistance of stainless steel decreases with the increase of carbon content.

The carbon content of most stainless steels is low, no more than 1.2%, and the WC (carbon content) of some steels is even less than 0.03% (such as 00Cr12). The main aluminum alloy element in stainless steel is Cr (chromium). The steel has corrosion resistance only when the Cr content reaches a certain value. Therefore, generally, the Cr (chromium) content of stainless steel is at least 10.5%. Stainless steel also contains elements such as Ni, Ti, Mn, N, Nb, Mo, Si and Cu. The main purpose stainless steel is not easy to produce erosion, crevice corrosion, rust or damage.

Stainless steel is still one of the raw materials with the largest compressive strength for engineering metal materials. Because stainless steel has good corrosion resistance, it can make the reasonable layout of components always connected with each other, so as to ensure the consistency of architectural engineering design. Magnesium containing stainless steel also integrates impact toughness and high additivity, which is convenient for the production, processing and manufacturing of components, and can meet the needs of architectural designers and staff of reasonable layout design scheme.