Welded steel pipe: A steel pipe produced by welding a steel plate or a strip of steel into a cylindrical shape. According to the welding method, it can be divided into arc welded pipe, high frequency or low frequency electric resistance welded pipe, gas welded pipe, furnace welded pipe, etc.; according to the weld form, it can be divided into straight welded pipe and spiral welded pipe.
Seamless steel pipe: Seamless steel pipe is a round, square and rectangular steel with a hollow section and no joints around it. The seamless steel pipe is formed by perforating a steel ingot or a solid tube blank, and then hot rolled, cold rolled or cold drawn. The seamless steel pipe has a hollow section and is used as a pipe for conveying fluid. Compared with a solid steel such as round steel, the steel pipe has a lighter weight when it has the same bending and torsional strength, and is an economical section steel which is widely used for manufacturing structures. Parts and mechanical parts, such as oil drill pipes, automotive drive shafts, bicycle frames, and steel scaffolding used in construction.
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