Seamless is a hollow section, no seams around a circular, square, rectangular steel. Seamless steel pipe is made of ingot or solid tube through the perforation capillary, then dial made of hot-rolled, cold-rolled or cold. Seamless steel tube with a hollow cross section, for a large number of solid steel pipes, steel pipes and round steel transmission fluid compared to the same torsional strength in bending, lighter weight, and is an economic cross-section steel, widely used in the manufacture of the structure parts and mechanical parts, such as drill pipe, automotive transmission, bicycle frames, and construction used in steel scaffolding.