Stainless steel pipe is a kind of hollow long round steel, which is mainly used in industrial transportation pipelines and mechanical structural components such as petroleum, chemical industry, medical treatment, food, light industry, mechanical instrument and so on. In addition, when the bending and torsional 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 commonly used to produce various conventional weapons, barrels, shells, etc.
1. Concentricity
The seamless tube is made by punching a hole in a stainless steel billet at a temperature of 2200°F, where the tool steel is punched and drawn to soften and spiral out of the hole. In this way, the wall thickness of the pipe is uneven and the eccentricity is high. Therefore, the wall thickness difference of the seamless pipe is allowed to be larger than that of the seamed pipe. Slotted tubes are made from precision cold rolled sheets (4-5 feet in width per coil). These cold rolled sheets typically 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. Slit tube wall thickness tolerances are tight and the wall thickness is very uniform across the circumference.
2. Welding performance
Generally, there are certain differences in the chemical composition of seamed pipes and seamless pipes. The steel composition for the production of seamless pipes is only the basic requirements of astm. The steel for the production of seamed pipes contains chemical compositions suitable for welding. For example, elements such as silicon, sulfur, manganese, oxygen, and trivalent ferrite are mixed in a certain proportion to produce a weld melt that is easy to transfer heat during the welding process, so that the entire weld seam can be penetrated. Steel pipes lacking the above chemical components, such as seamless pipes, will produce various unstable factors during the welding process, which are not easy to weld firmly and cannot be welded through.
