HIGH FREQUENCY ELECTRIC RESISTANCE WELDING
Following the development of low-frequency electric resistance welding process, the 1960s saw the introduction of a high-frequency electric resistance welding alternative. High-frequency electric resistance welding technology has since achieved widespread market penetration. The process involves the application of a high-frequency alternating current inthe range 200-500 kHz, with the tube forming and energy input operations being forformed by separate units. High-frequency welding method simultaneously utilizes pressure and heat in order to join the strip edges of the open-seam tube together without the addition of a filler metal. Squeeze and pressure rolls in the welding stand brign the edges of the open-seam tube gradually together and apply the pressure necessary for welding. High-frequancy alternating current offers a number of benefits as the energy source for generating the heat required for the welding process.