The difference between submerged arc welded spiral steel pipe and straight seam high frequency welde

Submerged arc welding spiral steel pipe uses continuous welding wire as electrode and filler metal. During operation, a layer of granular flux is covered on the welding area. The large-diameter spiral tube arc burns under the flux layer, melting the end of the welding wire and the local base metal. Under the action of arc heat, the upper part of the flux melts the slag and undergoes a metallurgical reaction with the liquid metal. The molten slag floats on the surface of the molten metal pool. On the one hand, it can protect the weld metal, prevent air pollution, and have a physical and chemical reaction with the molten metal to improve the strength and performance of the weld metal; on the other hand, it can also make the weld metal Slow down. Submerged arc welding can use a larger welding current, and the advantages are good weld quality and high welding speed. Therefore, it is especially suitable for welding large-diameter spiral steel pipes. And most of them use automatic welding, which has been widely used in the welding of carbon steel, low-alloy structural steel, and stainless steel.

High-frequency welding is a solid-phase resistance welding method. High-frequency welding can be divided into contact high-frequency welding and induction high-frequency welding according to the way that high-frequency current generates heat in the workpiece. In contact with high-frequency welding, a high-frequency current is introduced into the workpiece through mechanical contact with the workpiece. In induction high-frequency welding, the high-frequency current generates an induced current in the workpiece through the coupling action of the induction coil outside the workpiece. High-frequency welding is a highly specialized welding method, and special equipment should be equipped according to the product. High productivity, welding speed up to 30m/min. Using solid resistance heat as the energy source, the resistance heat generated by the high-frequency current in the workpiece is used to heat the surface layer of the workpiece welding area to a molten or close plastic state, and then the upsetting force is applied (or not) to realize the metal bonding.