Manufacturing Process of Thick-wall Welded Pipe

The production and manufacturing process of thick-wall welded pipe can be divided into three basic ways: cold drawing, cold rolling and hot rolling. The material of steel pipe is 10#, 20#, 35#, 45#, which is called ordinary steel pipe. 16Mn is between ordinary steel pipe and alloy steel pipe which is called low alloy steel pipe. The material of steel pipe is 27SiMn, 12Cr1MoV, 10CrMo910, 15CrMo, 35CrMo and stainless steel pipe is collectively called alloy steel pipe. It can be divided into seamless steel tubes for structure, seamless steel tubes for transportation, seamless steel tubes for boiler, high pressure seamless steel tubes for boiler, seamless steel tubes for fertilizer equipment, seamless steel tubes for geological brick exploration, seamless steel tubes for petroleum brick exploration, seamless steel tubes for petroleum cracking, seamless steel tubes for ships, cold drawn cold-rolled precision seamless steel tubes, and various alloy tubes.
 

API seamless steel pipe is mainly used for mechanical processing, coal mine, hydraulic steel, etc. Classification of thick-wall seamless steel tubes: hot rolled thick-wall seamless steel tubes, cold rolled thick-wall seamless steel tubes, cold drawn thick-wall seamless steel tubes, extruded thick-wall seamless steel tubes, pipe jacking. Stainless steel seamless steel tubes for structural use (GB/T 14975-1994) are hot-rolled (extruded, expanded) and cold drawn (rolled) seamless steel tubes made of stainless steel, which are widely used in chemical, petroleum, textile, medical, food, machinery and other industries for corrosion-resistant pipes, structural parts and components. Stainless steel seamless steel pipe for fluid transportation (GB/T 14976-1994) is a hot-rolled (extruded, expanded) and cold drawn (rolled) seamless steel pipe made of stainless steel for fluid transportation.   

Special shaped seamless steel pipe is the general term of API seamless steel pipe with other cross-section shapes besides round pipe. According to the different shapes and sizes of steel pipes, they can be divided into equal wall thickness special-shaped seamless steel pipes (code D), unequal wall thickness special-shaped seamless steel pipes (code BD), variable diameter special-shaped seamless steel pipes (code BJ). The special-shaped seamless steel pipe is widely used in various structural parts, tools and mechanical parts. Compared with the round pipe, the special-shaped pipe has larger inertia moment and section modulus, larger bending and torsion resistance, which can greatly reduce the structure weight and save steel.