Welded steel pipes are normally formed by crimping a steel plate or a steel strip then welding. According to the form of weld, it is divided into straight seam welded steel pipe and spiral welded steel pipe. the common forming processes of straight seam steel pipe are UOE forming process and JCOE steel pipe forming process. According to the application, it is divided into general welded pipe, galvanized welded pipe, blown oxygen welded pipe, wire casing, metric welded pipe, idler pipe, deep well pump pipe, automobile pipe, transformer pipe, electric welding thin wall pipe, electric welding special pipe and spiral welded pipe.
Generally welded steel pipes are used to deliver low pressure fluids, made of Q195A, Q215A, Q235A steel. It can also be made from other soft steels that are easy to weld. The steel pipe should be subjected to water pressure, bending, flattening, etc. The manufacturer can carry out higher-level testing according to its own conditions. The welded steel pipe usually has certain requirements on the surface quality. Usually, the delivery length is 4-10m, which can be required according to actual requirements. Manufacturers are available in fixed length or multiple sizes. The specification of the welded pipe is different from the actual one by the nominal diameter. The welded pipe has two kinds of thin-walled steel pipes and thick-walled steel pipes according to the specified wall thickness, steel pipe also is divided into two types according to the pipe end form: threaded and unthreaded.