Machinery industry is the main consumer of steel pipes, mainly including oil, cylinder pipes, hydraulic component pipes, shafts, shafts and rollers, as well as gas and liquid pipes of mechanical equipment. Seamless steel pipe accounts for 4% of the steel used in machinery industry. Therefore, the number of steel pipes used in the machinery industry in 2017 is estimated to be 6 million tons.


In 2017, China's shipbuilding completion may be the same as in 2016, with handheld orders of less than 90 million tons. For a ship weighing 10,000 tons, the total length of steel pipe is about tens of kilometers. Marine pipelines mainly include water supply and drainage, steam, fuel, hydraulic tubing and so on. The types of steel pipe include seamless steel pipe, LSAW pipe and high frequency LSAW pipe. The pressure is at least 0.7 MPa, the maximum is 40 MPa, the design temperature is 60 ~300 C, and the pipe diameter is 114 mm~610 mm. It is estimated that in 2017, the number of steel pipes in ships will be about 600,000 tons.


The cabs of automobiles and engineering machinery are mostly made of P-shaped cold-formed steel. At present, the wall thickness of square rectangular tube of automobile axle in our country is 16 mm. When the cold formed steel is formed by cold bending, the fillet is prone to crack when the wall thickness is larger than 14mm. Therefore, users usually entrust seamless steel pipe factory to produce this cold-formed steel. Hot rolled seamless rectangular tube developed and produced by Baotou Steel Seamless Steel Tube Plant is suitable for automobile axle rectangular tube. Its specifications are 150 mm x 160 mm x 16 mm, its material is Q345B, its yield strength is more than 345 MPa, and its tensile strength is more than 510 MPa. Elongation (> 21.0%), fillet requirement 30 ~40, average hardness 153HBW, meet user requirements. The thickness of hot-rolled seamless rectangular tube developed by Panzhihua Steel Seamless Steel Tube Plant can reach 18 mm, and the maximum specification is 300 mm x 300 mm.