Classification of Steel tube

By production method
Steel pipes can be divided into two categories according to production methods: seamless steel pipes and welded steel pipes, welded steel pipes are referred to as welded pipes.
1. Seamless steel pipe can be divided into hot rolled seamless pipe, cold drawn pipe, precision steel pipe, hot expanded pipe, cold spinning pipe and extruded pipe according to the production method.
Seamless steel pipe is made of high-quality carbon steel or alloy steel, which is divided into hot rolling and cold rolling (drawing).
2. Welded steel pipe is divided into furnace welded pipe, electric welded (resistance welded) pipe and automatic arc welded pipe because of its different welding processes, because of its different welding forms, it is divided into straight seam welded pipe and spiral welded pipe, and because of its end shape, it is divided into round welded pipe and special-shaped (square, flat, etc.) welded pipe.
Welded steel pipe is rolled into a tube-shaped steel plate to seam or spiral seam welding, in the manufacturing method, it is divided into low-pressure fluid transportation with welded steel pipe, spiral seam electric welded steel pipe, direct coil welded steel pipe, electric welded pipe, etc. Seamless steel pipes can be used in liquid air pressure pipelines and gas pipelines in various industries, etc. Welded pipes can be used for water pipelines, gas pipelines, heating pipes, electrical pipelines, etc.

Material classification
Steel pipes can be divided into carbon pipes and alloy pipes, stainless steel pipes, etc. according to the material of the pipe (that is, steel type).
Carbon tubes can be divided into ordinary carbon steel pipes and high-quality carbon structural tubes.
Alloy tubes can be divided into: low alloy tubes, alloy structural tubes, high alloy tubes, and high strength tubes. Bearing tubes, heat-resistant and acid-resistant stainless tubes, precision alloy (such as Kovar) pipes and superalloy tubes.

Classification of connection methods
Steel pipes can be divided into smooth pipes (pipe ends without threads) and wire turning tubes (pipe ends with threads) according to the connection mode of pipe ends.
Wire tubes are divided into: ordinary wire tubes and thickened wire tubes at the end of the tubes.
Thickened wire tubes can also be divided into: outer thickened (with external thread), inner thickened (with internal thread) and internal and external thickened (with internal and external threads) and other ground wire pipes.
If the wire tube is according to the thread type, it can also be divided into: ordinary cylindrical or tapered thread and special thread and other ground wire tubes.
In addition, according to the needs of users, the wire tube is generally delivered with pipe joints.