HIGH-FREQUENCY INDUCTION HEATING COIL, HIGH-FREQUENCY INDUCTION HEATING DEVICE AND METHOD OF MANUFACTURING WELDED PIPE

摘要

PROBLEM TO BE SOLVED: To provide a long-life time high-frequency induction heating coil having high weldability and a high-frequency induction heating device with the built-in high-frequency induction heating coil, and to provide a method of manufacturing a welded pipe by using the high-frequency induction heating device.;SOLUTION: A coil body 2 is formed by spirally winding a copper pipe 1 with three turns, and the outer surface of the copper pipe 1 is coated with a coating layer 3 made of a heat resistant coating material. The coating layers 3 having adjacent turns of the coil main body 2 are not in contact with each other with a gap formed between the coating layers 3. The heat resistant coating material of the coating layer 3 is an inorganic material, whose main component is silicon, silica, alumina or zirconia, etc., and pure water is made to flow inside the copper pipe 1. A nozzle 7 is mounted on the side of a coil part 4, and the coil part 4 is cooled with the outside cooling water ejected to the outer surface of the coil part 4. A nozzle 8 is mounted near the coil part 4, and N₂ gas is jetted from upstream into the inside of the coil part 4.;COPYRIGHT: (C)2002,JPO