Description

Alloy steel pipes are mainly used in high-pressure and high-temperature pipelines and equipment such as power plants, nuclear power plants, high-pressure boilers, high-temperature superheaters and reheaters. They are made of high-quality carbon steel, alloy structural steel and stainless heat-resistant steel, and manufactured by hot rolling (extrusion, expanding) or cold rolling (drawing).

One major advantage of alloy steel pipes is that they can be 100% recycled, which aligns with the national strategy of environmental protection, energy conservation and resource conservation. National policies encourage the expansion of application fields for high-pressure alloy pipes. At present, China’s consumption of alloy pipes accounts for only half of the total steel consumption in developed countries, and the expansion of application scenarios for alloy pipes provides broader room for industrial development. According to research by the expert group of the Alloy Pipe Branch of China Special Steel Association, the annual average growth rate of demand for long products of high-pressure alloy pipes in China will reach 10-12% in the future. Alloy pipes are defined by the production material (i.e., material grade) of steel pipes; as the name implies, they are pipes made of alloys. Seamless steel pipes, by contrast, are classified by production process (seamed or seamless), with seamed pipes including straight seam welded pipes and spiral pipes being the counterpart of seamless pipes.

Common material grades of alloy pipes include: 16-50Mn, 27SiMn, 40Cr, 12-42CrMo, 16Mn, 12Cr1MoV, T91, 27SiMn, 30CrMo, 15CrMo, 20G, Cr9Mo, 10CrMo910, 15Mo3, 15CrMoV, 35CrMoV, 45CrMo, 15CrMoG, 12CrMoV, 45Cr, 50Cr, 45CrNiMo and others.

Alloy steel pipes feature a hollow cross-section and are widely used as pipelines for transporting fluids such as petroleum, natural gas, gas, water and certain solid materials. Compared with solid steel materials like round steel, alloy steel pipes have a lighter weight while maintaining the same bending and torsional strength. As a kind of economical section steel, they are extensively used in the fabrication of structural components and mechanical parts, such as oil drill pipes, automobile transmission shafts, bicycle frames and steel scaffolding for construction engineering. Manufacturing annular parts with alloy steel pipes can improve material utilization, simplify production processes, and save materials and processing man-hours; typical applications include rolling bearing rings and jack sleeves, which are now commonly made from steel pipes. Alloy steel pipes are also indispensable materials for various conventional weapons, used in the production of gun barrels and artillery barrels. Alloy steel pipes can be divided into round pipes and special-shaped pipes according to cross-sectional shape. Given the same perimeter, a circular cross-section has a larger area, allowing round pipes to transport more fluid. In addition, the annular cross-section bears internal and external radial pressure with uniform stress distribution, which is why the vast majority of steel pipes are round.