Classification of stainless steel pipe

　　Classification of stainless steel pipe: stainless steel seamless steel pipe and stainless steel welded steel pipe are two basic categories. According to the outer diameter shape of steel pipes, they can be divided into round pipes and special-shaped pipes. Circular steel pipes are widely used, but there are also some square, rectangular, semi-circular, hexagonal, equilateral triangle, octagonal and other special-shaped steel pipes.

　　Hydraulic test and radiographic inspection shall be conducted for steel pipes under fluid pressure to check their pressure resistance and quality. It is qualified if there is no leakage, wetting or expansion under the specified pressure. Some steel pipes shall also be subject to crimping test, flaring test, flattening test, etc. according to the standards or the requirements of the demander.

　　Seamless stainless steel pipe, also known as stainless steel seamless pipe, is made of steel ingot or solid tube blank, which is perforated and then hot rolled, cold rolled or cold drawn. The specification of seamless steel pipe is expressed in millimeters of outer diameter and wall thickness.

　　The full name of 304 stainless steel pipe is SUS304 stainless steel pipe.

　　SUS304 stainless steel pipe belongs to the stainless steel pipe of American brand. The domestic brand is equivalent to 0Cr19Ni9 stainless steel pipe, which is usually replaced by 0Cr18Ni9.

　　The antirust mechanism of stainless steel is that alloy elements form a dense oxide film to isolate oxygen contact and prevent further oxidation.