Differences between submerged arc welding spiral steel pipe and straight seam high frequency welding steel pipe

Submerged arc welding spiral steel pipe uses continuous welding wire as electrode and filler metal. When working, a layer of granular flux is covered in the welding area. The arc of the large-diameter spiral pipe burns under the flux layer, melting the end of the welding wire and the local parent material to form a weld. Under the action of arc heat, the upper part of the flux melts the slag and reacts metallurgically with the liquid metal. The slag floats on the surface of the metal molten pool. On the one hand, it can protect the weld metal prevent air pollution, and produce physical and chemical reactions with the molten metal to improve the strength and performance of the weld metal; on the other hand, it can also slowly cool the weld metal. Submerged arc welding can use a larger welding current, and its advantages are good weld quality and high welding speed. Therefore, it is particularly suitable for welding large-diameter spiral steel pipes. Moreover, most of them use automated welding, which is currently 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 high frequency current generates heat in the workpiece. In contact high frequency welding, high frequency current is transmitted to the workpiece through mechanical contact with the workpiece. In induction high frequency welding, high frequency current generates induced current in the workpiece through the coupling effect 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. It has high productivity and the welding speed can reach 30m/min. With solid resistance heat as the energy source, the resistance heat generated by high frequency current in the workpiece is used during welding to heat the surface of the workpiece welding area to a molten or nearly plastic state, and then the forging force is applied (or not applied) to achieve the metal bonding.