Shaped seamless steel pipes are used in various structural parts, tools and mechanical parts. Compared with the round tube, the special-shaped tube generally has a larger moment of inertia and section modulus, and has a larger bending and torsion resistance, which can greatly reduce the structural weight and save steel.

The special-shaped pipe is generally distinguished according to the broken section. According to the material, it can be divided into seamless steel pipe special-shaped pipe, aluminum alloy special-shaped pipe, and plastic special-shaped pipe. The following mainly introduces the special-shaped steel pipe.

Steel pipe special-shaped pipe can be divided into oval special-shaped steel pipe, triangular special-shaped steel pipe, hexagonal special-shaped steel pipe, diamond-shaped special-shaped steel pipe, octagonal special-shaped steel pipe, semi-circular special-shaped steel circle, unequal hexagonal special-shaped steel pipe, five-petal plum-shaped special-shaped steel pipe , Double convex shaped steel pipe, double concave shaped shaped steel pipe, melon seed shaped shaped steel pipe, conical shaped shaped steel pipe, corrugated shaped shaped steel pipe.