The development of the pipe

　　In 1885, German Mannesmann brothers first invented the two roll cross rolling piercer. and in 1891, they also invented the periodic pipe rolling mill.

　　In 1903, Swiss R.C. stiefel invented the automatic pipe rolling mill (also known as the top end pipe rolling mill). Later, there were continuous pipe rolling mill, pipe jacking machine and other extension machines, which began to form the modern seamless steel pipe industry.

　　In 1930s, because of the adoption of three roll pipe rolling mill, extruder and periodic cold rolling mill, the variety and quality of steel pipes were improved.

　　In the 1960s, due to the improvement of the continuous rolling mill and the emergence of the three roll piercer, especially the success of the application of the tension reducing mill and the continuous casting billet, the production efficiency was improved, and the competitiveness of seamless pipe and welded pipe was enhanced.

　　In the 1970s, seamless pipe and Stainless Steel Screen Pipe are keeping pace, and the world steel pipe production is increasing by more than 5% every year.

　　Since 1953, China has attached great importance to the development of seamless steel tube industry, and has initially formed a production system for rolling various large, medium and small pipes. Generally, the copper tube is also made of ingot cross rolling and piercing, tube rolling machine rolling and coil drawing process.