Patent ID: 9604272
Date: 2017-03-28
CPC Classifications: B21D,C21D,H05B,Y02P

Claim:
1. A heating coil for carrying out induction heating of an elongated metal material while undergoing relative movement to an axial direction of the metal material with respect to the metal material without rotation of the metal material, the heating coil having at least a first 1-turn coil body which surrounds an outer periphery of the metal material in a circumferential direction and is spaced from the metal material and which has a first electrically insulating portion and a first electrical conductor, a second 1-turn coil body which is disposed in parallel with the first 1-turn coil body in the axial direction of the metal material and is spaced from the metal material and which substantially has the same shape and same size as the first 1-turn coil body and has a second electrically insulating portion and a second electrical conductor, and a body connecting portion which connects a first adjoining portion which adjoins the first electrically insulating portion in the circumferential direction and a second adjoining portion which adjoins the second electrically insulating portion in the circumferential direction, the body connection portion including a bend therein, characterized in that the first electrically insulating portion is disposed on a portion of the first 1-turn coil body in the circumferential direction and the second electrically insulating portion is disposed on a portion of the second 1-turn coil body in the circumferential direction and that when the first adjoining portion and the second adjoining portion are projected in a cross section which is perpendicular to a relative direction of movement of the induction heating coil with respect to the metal material, and when a non-effective coil length is Ln and the an inner coil length is L wherein the first electrically insulating portion and the second electrically insulating portion are not overlapped with each other when viewed from the axial direction.