Stainless steel pipe is a kind of hollow long round steel, which is mainly used in petroleum, chemical industry, medical treatment, food, light industry, mechanical appearance and other industrial transportation pipes and mechanical structural components. In addition, in bending. With the same torsional strength and light weight, it is also widely used to make mechanical parts and engineering structures of the square tube machine
. It is also used to produce all kinds of weapons, barrels, shells, etc.
The manufacturing process of seamless tube makes a hole punched in stainless steel billet at 2200 ° F. at this high temperature, tool steel becomes soft and spiral from the air after stamping and drawing. In this way, the wall thickness of the pipe is uneven and the degree of bias is high. Therefore, ASTM allows the wall thickness difference of seamless welded pipe to be larger than that of welded pipe. Seamed tubes are made of accurate cold-rolled sheets (4-5 feet in width per roll), the maximum wall thickness difference of these cold-rolled sheets is generally 0.002 inch, and the steel plate is cut into a width of π D, in which D is the outer diameter of the tube. The wall thickness of seamed pipe is very small, and the wall thickness of the whole circumference is very uniform.
2. Welding function
Generally, there are certain differences in the chemical composition of the square tube machine between the sewn tube and the seamless tube. The steel composition of seamless pipe is only the basic requirement of ASTM. The steel produced with welded pipe contains a kind of welding melt which is easy to transfer heat during the welding process, so that the whole weld is fully penetrated. The square tube machine without the above chemical composition, such as seamless tube, will have various unstable factors in the welding process, which is not easy to be welded firmly and not fully penetrated.