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　　Seamless steel pipe is a kind of round, square and rectangular steel with hollow section and no joint around it. Seamless steel Pipe is made of steel ingot or solid billet through perforation and then hot-rolled, cold-rolled or cold-drawn. Seamless steel pipe has hollow section, which is widely used as pipeline for conveying fluid. Compared with solid steel such as round steel, New Design 18 Inch Seamless Steel Pipe With Great Price  has lighter weight when its bending and torsion strength is the same. It is an economic section steel, and is widely used in manufacturing structural parts and mechanical parts, such as steel scaffolding for oil drills.

　　The German Manisman Brothers first invented the two-roll cross-rolling piercing mill in 1885, and the periodic pipe mill in 1891. In 1903, the Swiss R.C. Stiefel invented the automatic pipe mill (also known as the top pipe mill). Later, various extension machines, such as continuous pipe mill and pipe jacking machine, began to form the modern seamless steel pipe industry.

　　In the 1930s, three-roll pipe mill, extruder and periodic cold rolling mill were used to improve the quality of steel pipes. In the 1960s, with the improvement of continuous rolling mill and the emergence of three-roll piercing mill, especially the successful application of stretch reducing mill and continuous casting slab, the production efficiency was improved and the competitiveness between seamless pipe and welded pipe was enhanced. In the 1970s, seamless steel pipes and welded steel pipes were going hand in hand, and the world steel pipe production increased at a rate of more than 5% per year.

　　Since 1953, China has attached great importance to the development of seamless steel pipe industry, and has initially formed a production system for rolling various large, medium and small pipe. Copper tubes are also generally made by cross-rolling perforation of ingot billets, rolling of tube mills and stretching of coils.

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