The submerged arc welding spiral steel pipe uses continuous welding wire as the electrode and filler metal. During work, a layer of granular flux is covered in the welding area. The arc of the large-diameter spiral pipe burns under the flux layer to melt 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 slag floats on the surface of the molten metal 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 quality and performance of the weld metal; on the other hand, it can also make the weld metal Cool down slowly. The advantages of submerged arc welding that can use a larger welding current 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 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, the high-frequency current generates an induced current in the workpiece through the coupling effect of the external induction coil of 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 in the workpiece by a high-frequency current is used during welding to heat the surface of the welding zone of the workpiece to a molten or close to a plastic state, and then apply (or not apply) upsetting force to achieve metal bonding.
Post time: Dec-22-2022