The difference between seamed stainless steel pipe and seamless stainless steel pipe

Stainless steel pipe is a hollow long round steel, which is widely used in petroleum, chemical, medical, food, light industry, mechanical instrumentation and other industrial pipelines and mechanical structural parts. In addition, when the bending and torsion strength are the same, the weight is lighter, so it is also widely used in the manufacture of mechanical parts and engineering structures. It is also often used to produce various conventional weapons, barrels, shells, etc.
1. Concentricity

The manufacturing process of the seamless tube is to punch a hole in a stainless steel billet at a temperature of 2200°f. At this high temperature, the tool steel is punched and drawn to become soft and spirally formed from the hole. In this way, the wall thickness of the pipeline is uneven and the eccentricity is high. Therefore, the wall thickness difference of the seamless pipe is allowed to be greater than the wall thickness difference of the slit pipe. The slotted pipe is made of precise cold-rolled sheet (with a width of 4-5 feet per coil). These cold-rolled sheets usually have a maximum wall thickness difference of 0.002 inches. The steel plate is cut to a width of πd, where d is the outer diameter of the pipe. The tolerance of the wall thickness of the slit pipe is very small, and the wall thickness is very uniform throughout the circumference.
2. Welding performance
Generally, there is a certain difference between the chemical composition of seamed pipes and seamless pipes. The steel composition for producing seamless pipes is only the basic requirement of astm. The steel used to produce seamed pipes contains chemical components suitable for welding. For example, the mixing of elements such as silicon, sulfur, manganese, oxygen, and trivalent 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, and are not easy to weld firmly and impermeably.

Production process of welded steel pipe

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