What is the difference between HFW and ERW?
Date:2016-01-20 View(s):6724 Tag:high frequency welding, electric resistance welding, welded steel pipe manufacturer
High-frequency welding (HFW) is a solid resistance heat energy. The use of high-frequency current welding resistance heat generated in the workpiece so that the workpiece is heated to melt the welding area or near the surface of the plastic state, then applied (or not applied) forging force and achieve a combination of metals. Therefore, it is a solid phase resistance welding. High-frequency welding: high-frequency current through the metal conductor, will produce two peculiar effects: skin effect and proximity effect, high frequency welding is performed using these two effects of the welded steel pipe, these two effects is to realize a metal at high frequency welding base. High frequency welding is the use of the skin effect of high-frequency energy is concentrated on the surface of the current workpiece; the use of proximity effects to control the position and extent of the flow path of the high frequency current. Current speed is very fast, it can be in a very short period of time the adjacent plate edge heated, melted, and extruded through docking. Frequency welding method according to a high frequency current to generate heat in the workpiece can be divided into to contact with high-frequency welding and high frequency induction welding. Contact frequency welding, high frequency current through the mechanical contact with the workpiece while the workpiece passed. High frequency induction welding, the high-frequency current through the coupling of the workpiece external induction coil to generate induced currents in the workpiece. High-frequency welding is a highly specialized welding method, according to the product is equipped with special equipment. High productivity welding speeds of up to 30m/min. Mainly used for longitudinal seam or spiral seam welded pipe manufacturing.
Electrical resistance weld (ERW) is the combination of applying pressure to the workpiece through the electrode, a method using welding current through a resistor in thermal contact with the joint surface and the surrounding area generated. Resistance by the current flowing through the thermal effect of resistance welding a workpiece contacting surface of the surrounding area is heated to produce molten or plastic state, so as to form a metal bonding method. There are four main resistance welding method that spot, seam welding, projection welding, butt welding. Resistance welding uses a pressure-free filler metal welding, the weld is not filled with other ingredients, skin effect against high frequency current and proximity effect, the plate is heated to welding temperature side instantly, formed by the squeeze roller extrusion weld forging organization. Require the use of high-quality steel pipe weld heat treatment online or offline, so that the weld zone structure refinement, quality ERW pipe weld and base metal may reach the same level of toughness, which is submerged arc welding process can not be achieved.
