INDUCTION HEATING COIL DEVICE FOR MANUFACTURING OF WORKPIECE AND MANUFACTURING METHOD

摘要

Disclosed is an induction heating coil capable of heating a steel tube that is conveyed non rotationally in the axial direction thereof uniformly in the circumferential direction thereof and stably in a narrow range in the axial direction thereof. An induction heating coil (10) having a configuration that encircles the exterior circumference of a long metallic material (1) which is the object to be heated in the circumferential direction thereof comprises two or more coil loops: a first coil loop coil main body (11) and a second coil loop coil main body (12). The coils have an interior circumferential length Ln (the non efficacious coil length) wherein the number of effective coil loops when the coils are projected in the circumferential direction is less than the total number of coil loops and the interior circumferential length of the projected coil main body being L0 (the interior circumferential coil length) where Ln/Lo is less than or equal to 0.05; and the coil main body (11) and the coil main body (12) further comprise insulator portions (11b and 12b) upon connection portions thereof wherein the insulator portions are present in locations separated between 5 and 45 degrees upon the central angles of the coil main bodies.