A steel with a hollow section longer than the diameter or circumference.According to the section shape, it is divided into circular, square, rectangular and special-shaped steel pipes.It is divided into carbon structural steel pipe, low-alloy structural steel pipe, alloy steel pipe and composite steel pipe.According to the purpose, it is divided into pipeline, engineering structure, thermal equipment, petrochemical industry, machinery manufacturing, geological drilling, high pressure equipment for steel pipe, etc.According to the production process is divided into seamless steel pipe and welded steel pipe, seamless steel pipe and hot rolling and cold rolling (pull) two, welded steel pipe and straight seam welded steel pipe and spiral seam welded steel pipe.
Steel pipe is not only used for transporting fluid and powdery solids, exchanging heat energy, making mechanical parts and containers, it is also a kind of economical steel.Using steel pipe to manufacture structural net frame, pillar and mechanical support, can reduce light weight, save 20 ~ 40% of metal, and can realize factory mechanized construction.Using steel pipe to manufacture highway Bridges can not only save steel and simplify construction, but also greatly reduce the area of protective coating, saving investment and maintenance costs.
By production method
Steel pipe can be divided into two categories according to the production method: seamless steel pipe and slit steel pipe, slit steel pipe is referred to as straight seam steel pipe.
1. Seamless steel pipe can be divided into: hot rolled seamless pipe, cold drawn pipe, precision steel pipe, hot expanding pipe, cold spinning pipe and extrusion pipe, etc.Seamless steel tube with high quality carbon steel or alloy steel, hot rolling, cold rolling (pull).
2. The welded steel pipes are divided into furnace welded pipes, electric welded pipes (resistance welded pipes) and automatic arc welded pipes due to different welding processes. The welded pipes are divided into straight welded pipes and spiral welded pipes due to different welding forms.
Welded steel pipe is made of tubular steel plate welded to seam or spiral seam. In terms of manufacturing method, it is divided into welded steel pipe for low-pressure fluid transportation, spiral welded steel pipe, direct welded steel pipe and electric welded pipe.Seamless steel pipe can be used in various industries of liquid pressure pipe and gas pipe.Welding pipes can be used for water pipes, gas pipes, heating pipes, electrical pipes, etc.
According to the material
Steel pipe by tube material (that is, steel) can be divided into: carbon pipe and alloy pipe, stainless steel pipe.
Carbon pipe can be divided into ordinary carbon steel pipe and high quality carbon structure pipe.
Alloy pipe can be divided into: low alloy pipe, alloy structure pipe, high alloy pipe, high strength pipe.Bearing pipe, heat and acid resistant pipe, precision alloy (such as cutting alloy) pipe and high temperature alloy pipe.
By section shape
Steel products of steel and variety of specifications are very wide, its performance requirements are various.All these should be distinguished by changes in user requirements or working conditions.Generally, steel pipe products are classified by section shape, production method, pipe material, connection mode, coating characteristics and application, etc.
Steel pipe can be divided into circular steel pipe and special-shaped steel pipe according to the shape of cross section.
Profiled steel pipe refers to all kinds of non-circular circular section steel pipe.Among them, there are: square pipe, rectangular pipe, elliptic pipe, flat elliptic pipe, semicircle pipe, hexagonal pipe, hexagonal inner pipe, non-equilateral hexagonal pipe, equilateral triangle pipe, pentagonal plum pipe, octagonal pipe, convex pipe, biconvex pipe.Double concave tube, multi concave tube, melon seed tube, flat tube, diamond tube, star tube, parallelogram tube, ribbed tube, drop tube, internal fin tube, twisted tube, B type tube, D type tube and multi-layer tube, etc.
Steel pipe is divided into equal section steel pipe and variable section steel pipe.Steel pipe with variable section (or section) refers to the steel pipe with periodic or non-periodic changes in section shape, internal and external diameter and wall thickness along the pipe length.The main products are: tapered pipe, tapered pipe, stepped pipe, stepped pipe, periodic section pipe, corrugated pipe, spiral pipe, steel pipe with heat sink and gun barrel with double wire, etc.