I、 Tube Classification
1、according to production methods classification

（1）seamless pipe - hot-rolled pipes, cold-rolled pipes, cold-drawn tubes, extruded tubes, pipe jacking                                                                                                                   （2）Welded Pipe    

（a）in accordance with sub-processes - arc welded pipe, ERW pipe (high frequency, low frequency), gas pipe, furnace pipe
（b）by weld points - Longitudinal Welded Pipe, Spiral Welded Pipe
2、in accordance with section shape classification
（1）easy-section steel tube - circular steel tube, square steel pipe, steel tube oval, triangular steel pipe, steel pipe hexagonal, diamond-shaped steel tube, steel pipe octagonal, semi-circular steel, other
（2）the complexity of cross-section steel tube - scalene hexagonal steel pipe, five plum-shaped steel tube, steel tube double-convex, double concave steel pipe, melon-shaped steel tube, conical steel pipe, corrugated-shaped steel tube, steel pipe watchcase, other
3、classified according to wall thickness - thin-walled steel pipe, thick-walled steel pipe
4、by end-use Category - pipe with steel pipe, steel pipe for thermal
equipment, machinery for industrial use steel pipes, petroleum, geological drilling using steel pipe, steel tube container, chemical industrial steel pipes, special-purpose steel pipes, other
II、seamless steel pipe
Is a hollow cross-section, not the joints surrounding the steel bar. Steel tube with a hollow cross-section, a large number of pipes used for conveying fluids, such as transmission oil, natural gas, gas, water and some solid materials, such as pipelines. Steel tube with solid steel round bar, etc. as compared to the flexural torsional strength in the same light, is an economic cross-section steel, widely used in the manufacture of structural parts and mechanical parts, such as the oil pipe, automotive transmission shaft, bicycles aircraft, as well as building construction, such as using steel scaffolding. With steel pipe manufacturing annular parts, can improve material utilization, simplify the manufacturing process, saving material and machining time, such as roller bearing rings, Jack sets and so on, has been widely used to manufacture steel pipes. Steel pipe or a variety of conventional weapons an indispensable material, barrel, barrel must be steel pipe, etc. to create. Steel tube by cross-sectional area can be divided into different shapes tube. Because of the circumference of the same conditions, the largest circle, using a circular tube can be more fluid delivery. In addition, the ring cross-section in the bearing radial internal or external pressure, the force more evenly, so the vast majority of tubular steel pipes are. However, the tube also has some limitations, such as in-plane bending conditions, the pipe on the better side, rectangular tube bending strength, and a number of sets of frames, Steel-wood furniture on the commonly used square, rectangular tube. According to different purposes need to have other shaped cross-section shape steel pipe.
1.Structural Seamless Steel Tube (GB/T8162-1999) are for general structure and the mechanical structure of the seamless steel pipe.
2.Fluid with seamless steel pipe (GB/T8163-1999) are used for conveying water, oil, gas and other fluids in general seamless steel tubes.
3.Low Medium Pressure Boiler Seamless Steel Tube (GB3087-1999) are used in the manufacture of various structural low and medium pressure boiler superheated steam pipes, boiling water pipes and superheated steam locomotive boiler tubes, opium pipe, tobacco pipe and a small brick arch effective high-quality carbon structural steel hot-rolled and cold-drawn (rolled) seamless steel pipe.
4.High-pressure boiler seamless steel pipe (GB5310-1995) are used in the manufacture of high-pressure and over pressure water tube boiler heating surface with high-quality carbon steel, alloy steel and heat-resistant stainless steel seamless steel pipe.
5.Fertilizer equipment with high pressure seamless steel pipe(GB6479-86) are applicable to the work temperature -40 ~ 400 ℃, working pressure of 10 ~ 30Ma chemical equipment and pipeline quality carbon structural steel and alloy steel seamless steel pipe.
6.Petroleum Cracking Seamless Steel Tubes (GB9948-88) are applicable to the oil refinery furnace tubes, heat exchangers and pipe seamless steel pipe.
7.Geological Drilling Pipe(YB235-70) for the geological departments of the steel pipe used to drill cores, by end-use can be divided into the drill pipe, drill collar, core tubes, casing tubes, etc. and sediments.
8.Diamond core drilling with seamless steel pipe (GB3423-82) are used for diamond core drilling drill, core rod, casing of seamless steel tubes.
9.Oil drilling pipe (YB528-65) are used for oil drilling at both ends within the thickening or thickening of the seamless steel pipe outside. Steel tube sub-car wire and wire the two cars, car wire connector useful links, not cars welded wire effective methods and tools for joint connection.
10.Ship carbon steel seamless pipe(GB5213-85) is to create a ship I level pressure piping, Ⅱ grade pressure piping, boilers, and overheating of the carbon steel seamless steel pipe transparencies. Carbon steel seamless steel pipe wall temperature does not exceed 450 ℃, alloy steel seamless steel pipe wall temperature exceeds the work of 450 ℃.
11.Automobile axle casing with seamless steel pipe (GB3088-82) are manufacturing automobile axle casing and drive shaft Bridge shell effective quality carbon structural steel and alloy structural steel hot-rolled seamless steel tubes.
12.Diesel engine with high pressure oil pipe(GB3093-86) is to create effective high-pressure diesel injection system of cold-drawn seamless steel tub
III、Welded Steel Pipes & Tubing
Welded steel pipes and tubing are used in a number of applications where high demands are set on reliability, strength and corrosion resistance. These high performance pipes and tubes are alloyed with higher contents of molybdenum and nitrogen in order to improve the corrosion resistance and the strength, and are welded with over alloyed filler metals and/or with nitrogen added to the shielding gas, in order to become as high pitting corrosion resistance as possible in the weld.
Pipes made of nitrogen alloyed chloride resistant grades in the presented applications are welded with the addition of nitrogen in the shielding gas. Most of the pipes are also welded with filler metal and heat treated when specified. Welded steel pipes and tubing come in improved design properties and are much higher corrosion resistance than other conventional steel pipes.
Depending on how and where the pipes will be used it is up to the end user to decide which type of heat treatment is necessary. Chloride environments give however a risk for pitting, crevice and stress corrosion for standard steels. The pipes are used in all types of corrosive environments in industries such as, chemical, metallurgical, energy, oil & gas, pulp & paper, ships, desalination, and food.

II、 III、Welded Steel Pipes & Tubing