Black steel pipe used for conveying fluidand solid, not only to exchange heat, manufacturing machinery parts and container, it is also a kind of economic steel. With black steel pipemanufacturing space truss structures, pillar and mechanical support, can reducelight weight, saving metal 20 ~ 40%, and can realize the mechanization offactory construction. Black steel pipe manufacturing highway Bridges not onlycan save steel, simplify construction, and can greatly reduce the area of thecoating layer, save investment and maintenance costs.

So, any other types of steel cannotcompletely replace steel tube, but the steel tube can replace part of theprofile and bar. Black steel pipe to the national economic development andimprovement of quality of human life, is far better than the other steelproducts. From People's Daily appliances, furniture, water supply and drainage,gas supply, ventilation and heating facilities to various kinds of agriculturalmachinery equipment manufacturing. The development of underground resources,defense and aerospace used guns, bullets, missiles, rocket is inseparable fromthe steel tube and so on.

Because of the steel tube is closely connectedwith human life and production activities, production technology of black steelpipe industry has developed rapidly, not only bring forth the fresh, Also black steel pipe production in iron and steel industry occupies an irreplaceableposition. Black steel pipe and welded pipe, is to use steel plate or steelstrip after crimp molding made of welded steel pipe. The technology ofproducing black steel pipe is simple and the production efficiency of it ishigh, but the general strength of the black steel pipe is lower than that ofthe seamless steel tube. This can increase the profiles of the black steelpipe. The seamless steel tube is instead in the field. The welded steel pipeformed according to the weld seam welded pipe and the spiral welded pipe.

The technology of straight seam welded pipeproduction is also simple, and with high production efficiency, low cost and rapid development. The strength of the straight seam API steel pipe is lowerthan that of the black steel pipe, which uses a narrow billet production with asmaller diameter welded pipe. Also you can adopt the production of the samewidth of billet with different pipe diameter welded pipes. If compared with thesame length of straight seam pipe, its length is 30~100 percent and its productionspeed is low. As a result, a small diameter black steel pipe is mostly withstraight seam welding, large diameter welded pipe for the most part adoptsspiral welded. These profiles of black steel pipe are used for transportingoil, gas, air, water, heating steam and so on