The biggest advantage of large-diameter alloy steel pipe is that it can be recycled 100%, and it is in line with the national strategy of environmental protection, energy saving and resource conservation. The national policy encourages the expansion of the application of high-pressure alloy pipe. At present, the consumption of large-diameter alloy steel pipes in China accounts for only half of the total amount of steel. The use of large-diameter alloy steel pipes has expanded to provide a broader space for the development of the industry. According to the research of the China Special Steel Association's alloy steel pipe branch, the demand for large-diameter alloy steel pipe long products in China will increase by an average of 10-12% in the future. Alloy tube and seamless tube are both related and different and cannot be confused. Large-diameter alloy steel pipe is defined according to the production material (that is, material), as the name suggests is the alloy pipe; and seamless pipe is defined according to the production process (seamless seamless), different from the seamless pipe There is a seam pipe, including straight seam welded pipe and spiral pipe. The material of alloy steel pipe is roughly: 10#, 20#, 35#, 45#, 16-50Mn, 27SiMn, 40Cr, 12-42CrMo 16Mn 12Cr1MoV T91 27SiMn 30CrMo 15CrMo 20G Cr9Mo 10CrMo910 15Mo3 15CrMoV 35CrMoV 45CrMo