Seamless pipe is a long steel strip with a hollow cross-section and no seams around it. It is made of a whole round steel with holes and no welds on the surface, so it is called seamless pipe or seamless steel pipe. Seamless pipes can be divided into hot-rolled seamless pipes, cold-rolled seamless pipes, cold-drawn seamless pipes, extruded seamless pipes, etc. according to the production method, and can be divided into round and special-shaped pipes according to the cross-sectional shape. Special-shaped pipes include square, oval, triangle, hexagon and other shapes.