1.4833 / 309s Stainless Steel Round Pipe | Stainless Steel Square Tube

Alternative grades of equivalent materials

Standard Specification Of 309s Pipe / Tube

The difference between seamless stainless steel pipe and seamed steel pipe

1. There are certain differences in the chemical composition of stainless steel seam pipes and stainless steel seamless pipes. The steel composition for the production of seamless pipes is only the basic requirement of astm. The steel used for the production of seamed pipes contains chemical components suitable for welding. For example, the mixing of elements such as silicon, sulfur, manganese, oxygen, and triangular ferrite in a certain proportion can produce a weld melt that is easy to transfer heat during the welding process, so that the entire weld can be penetrated. Steel pipes lacking the above chemical composition, such as seamless pipes, will produce various unstable factors during the welding process, which are not easy to weld firmly and impermeably.

2. The quality of seam stainless steel welded pipe is better than that of stainless steel seamless pipe:
Because the seamed stainless steel pipe is made of accurate cold-rolled sheet that has passed inspection, any defects are limited to the weld. Seamless pipes are stamped from stainless steel blanks by punches, resulting in many tearing phenomena in the pipe wall formed by extrusion. The eddy current test shows that the defective rate of seamed stainless steel pipes is generally lower than that of seamless stainless steel pipes. Using ultrasonic testing, the background noise of seamless stainless steel welded pipes is so great that it is difficult to find defects. The background noise of seamed stainless steel welded pipes is very low, and it is easy to find defects.

3. The manufacturing process of the stainless steel seamless pipe is to punch a hole in the stainless steel billet at a temperature of 2200°f. At this high temperature, the tool steel becomes soft and spirally formed from the hole after punching and drawing. come out. In this way, the wall thickness of the pipeline is uneven and the degree of eccentricity is high. The wall thickness difference of the slit pipe is larger than the wall thickness difference of the slit pipe. Since the stainless steel seamed pipe is made of precise cold-rolled plates, the wall thickness tolerance of the seamed pipe is very small, and the wall thickness is very uniform throughout the circumference.