Molding process of the steel tube
1, welded steel pipe is welded, it is cut into by the steel strip narrow steel strip, and then wrapped into a tubular shape with the cold mold. And special welding then a pipe seam welding. Outside welds polished bright. Within the burr of the pipe is not to fight. The only precision welded to fight within the burr.
2, seamless steel pipe is cylindrical ingot hot pull into a tube, so can not see the weld.

Use classification of steel pipe:
1, water gas pipe is commonly used welded steel pipes, transport fluid and gas called, to feel the pressure, so are relatively thick wall. Older know, rich from poor, a lot of it is called with the characteristics of the times, not too seriously. Original which money galvanized Yeah, two brush paint on the line. Black Well, call it black iron pipe.
2, the conduit is to wear a wire and thin-walled tube. At that time only the standard, no one production. In fact, the eighties and nineties of gas pipes with water.
3, galvanized iron pipe is galvanized welded steel pipe. Galvanized inside and outside, water can be transported. Let Electric used when threading. General are relatively thin wall. Now on the market is poor. Elbow bend angle to blast hole.

Anti-corrosion classfication of steel pipe:
Steel pipe: steel pipe is open at both ends and having a hollow cross-section and their relatively large length, and the vicinity of the steel can be divided, according to the production method of seamless and welded steel pipe, pipe specifications Dimensions (such as diameter or side length) and wall thickness, a very wide range of sizes, from a small diameter capillary tube until the large-diameter up to several meters in diameter. The steel pipe can be used for pipes, thermal equipment, industrial machinery, petroleum exploration, container, chemical industry and for special purposes.

Seamless steel pipe: seamless steel pipe is made from a single piece of metal on the surface of steel pipe joints. Production methods can be divided into hot-rolled pipes, cold rolled tubes, cold drawn tubes, extruded tube. Can be divided into two kinds of round and shaped cross-sectional shape. The seamless pipe of the maximum diameter of 650 mm (enlarged diameter tubes), a minimum diameter of 0.3 mm (capillary). According to different thickness can be divided into thick-walled pipes and thin-walled tube. Seamless pipe is mainly used for the petroleum exploration tube, petrochemical cracking tubes, boiler tubes, the bearing tube as well as the automotive, aerospace steel and other high-precision structure.

Welded steel pipe: welded steel pipe refers to the bending deformation of the steel strip or steel sheet as round, square and other shapes and then welded into the steel pipe, the surface of the seam. According to the different welding methods can be divided into the arc welded pipe, high or low frequency electric resistance welded pipe, gas pipe, stove pipe, Bundy tube. Weld shape can be divided into Longitudinal and spiral welded pipe. Welded steel pipe used for oil drilling and machinery manufacturing. The furnace can be used as a water pipe and gas pipe, large diameter welded pipe used for high-pressure oil and gas transmission; spiral welded pipe for oil and gas transmission pipe piles, piers. The welded steel pipe is lower than the cost of seamless steel, high production efficiency.