Seamless steel pipes are perforated from whole round steel, and steel pipes without welds on the surface are called seamless steel pipes. According to the production method, seamless steel pipes can be divided into hot-rolled seamless steel pipes, cold-rolled seamless steel pipes, cold-drawn seamless steel pipes, extruded seamless steel pipes, and top pipes. According to the cross-sectional shape, seamless steel pipes are divided into two types: round and special-shaped. Special-shaped pipes have square, elliptical, triangular, hexagonal, melon-shaped, star-shaped, and finned pipes. The maximum diameter is 900mm and the minimum diameter is 4mm. According to different uses, there are thick-walled seamless steel pipes and thin-walled seamless steel pipes. Seamless steel pipes are mainly used as petroleum geological drilling pipes, cracking pipes for the petrochemical industry, boiler pipes, bearing pipes, and high-precision structural steel pipes for automobiles, tractors, and aviation.

Seamless steel pipes are characterized by good pressure resistance and confined.

Features of spiral tube: Straight seam welded pipe has simple production process, high production efficiency and low cost. The strength of spiral welded pipe is generally higher than that of straight welded pipe. It can produce narrow welded pipe with narrow blank, and can also use the same width. The billet is produced with different diameters of the welded pipe. However, compared with the straight pipe of the same length, the weld length is increased by 30 to 100%, and the production speed is low. Therefore, most of the smaller diameter welded pipes are straight seam welded, and the large diameter welded pipes are mostly spiral welded.

But with the same length straight seam pipe, compared to weld length increases 30 ~ 100%, and the production speed is low. Therefore, a small-bore tube welding mostly adopts the straight seam welding, large diameter welded pipe is mostly using spiral welded.

Spiral steel pipe type is made by strip, seamless steel tube type is made by round steel, difference is very big, production process different:
spiral tube is to use strip steel welding, can see the weld;

Seamless pipe is made with round steel punched, spiral tube wall thickness difference under very big, and seamless tube small tube under basic no difference, the difference for bassoon and will not many.