1. High frequency welding process of straight seam steel pipe: according to the way in which the high frequency current generates heat in the workpiece can be divided into high frequency welding by contact and high frequency welding inductively. When in contact with high frequency welding, high frequency current is transmitted to the workpiece through mechanical contact with the workpiece. In the induction of high frequency welding, the high frequency current generates an induced current in the workpiece through the coupling action of the external induction coil of the workpiece. High frequency welding is a specialized welding method that requires special equipment according to the product. High productivity and welding speed of 30m / min. That is, the welding is parallel to the surface of the steel pipe and will not be higher or lower than the surface of the steel pipe.
2. Submerged arc welding process of straight seam pipe: Submerged arc welded steel pipe is also a welding method that uses the arc as a heat source. In submerged arc welding, the arc burns under the cover of a layer of granular meltable flow, and the arc light is not exposed. Submerged arc welding is named after this. The metal electrode used was a bare wire that was fed without interruption. Because submerged arc welding has a high penetration depth, high productivity and high degree of mechanical operation, it is suitable for welding long welds of medium and heavy plate structures. It is widely used in shipbuilding, boilers and pressure vessels, bridges, overweight machinery, nuclear power plant structures, marine structures, weapons, etc. It is one of the most used welding methods in the production of welded steel tubes. .