Classified by Production Methods 1. Seamless Steel Pipe - hot rolled seamless steel pipe, cold rolled seamless steel pipe, cold drawn seamless steel pipe2. Welded Steel Pipe - longitudinal welded pipe, spiral welded pipe, electric resistance welded pipeClassified by Cross-sectional Shape1. Simple section steel pipe - round carbon steel pipe, square carbon steel pipe, rectangular carbon steel pipe, oval carbon steel pipe ect. 2. Complex section steel pipe - hexagonal carbon steel pipe with unequal edge, five plum shaped carbon steel pipe, double convex carbon stee pipe, double concave carbon steel pipe ect.

Straight seamless steel pipe wall thickness control is a difficult production. At present, the straight seam steel pipe manufacturers to improve the wall thickness in the production of precision uses the methods generally including:1, Tube heating Heating to the average to prevent rapid up and down temperature. Each take-off and landing temperature is to maintain a smooth slow, the maximum rise and fall temperature does not exceed 30 ℃.2, Rolling mill mandrel Average wall thickness of thick wall tube and solid billet make the probability of mandrel bending deformation significantly reduced, can effectively improve the wall thickness of the precision.