GB/T14291-1992 (mineral fluid transport welded steel pipe). It is mainly used for straight seam welded steel pipes for mine pressure, drainage and shaft discharge. It represents the material Q235A, B grade steel. GB/T14980-1994 (large diameter electric welded steel pipe for low pressure fluid transportation). It is mainly used to transport low pressure fluids such as water, sewage, gas, air, heating steam and other uses. It stands for material Q235A grade steel.

Seamless pipe for low and medium pressure boilers (GB3087-1999) is used for the manufacture of superheated steam pipes, boiling water pipes and locomotive boiler superheated steam pipes, large smoke pipes, small smoke pipes and arch brick pipes for various structures. High-quality carbon structural steel hot-rolled and cold-drawn (rolled) seamless steel tubes.

With the development of society, the output of steel is gradually increasing, and the demand is increasing. Therefore, the development of modern cities cannot be separated from carbon steel tubes. Carbon steel tubes are widely used, such as the construction of electrified high-speed railways, substations, and communication facilities.

Stainless steel is referred to as stainless steel, it is composed of stainless steel and acid steel two parts, in short, can resist atmospheric corrosion of steel called stainless steel, and can resist the corrosion of chemical media steel called acid steel. Generally speaking, chromium content Cr more than 12% steel has the characteristics of stainless steel according to the microstructure of stainless steel after heat treatment can be divided into five categories: ferritic stainless steel, martensitic stainless steel, austenitic stainless steel, austenitic - ferritic biphase stainless steel and precipitation hardened stainless steel.