Steel with a hollow section whose length is much greater than its diameter or circumference. According to the cross-sectional shape, it is divided into circular, square, rectangular and special-shaped steel pipes; according to the material, it is divided into carbon structural steel pipes, low alloy structural steel pipes, alloy steel pipes and composite steel pipes; Steel pipes for thermal equipment, petrochemical industry, machinery manufacturing, geological drilling, high-pressure equipment, etc.; according to the production process, they are divided into seamless steel pipes and welded steel pipes, among which seamless steel pipes are divided into hot-rolled and cold-rolled (drawn) Two kinds, welded steel pipe is divided into straight seam welded steel pipe and spiral seam welded steel pipe.
The steel pipe is used to transfer fluid and powder, exchange heat and produce mechanical parts and containers, what's more it's a kind of economical steel. Using steel pipes to manufacture building structure grids, pillars and mechanical supports can reduce weight, save 20-40% of metal, and realize factory-like mechanized construction. The use of steel pipes to manufacture highway bridges can not only save steel and simplify construction, but also greatly reduce the area of the protective layer, saving investment and maintenance costs.
