| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a coil for induction-heating with which a heat treatment in which hardness and toughness are well balanced can be performed. <P>SOLUTION: A small diameter part 13 is formed between the one end part 11 and the end part 12 of the coil 1 for induction-heating. A metallic member to be heated is heated at the maximum temperature when the member passes through the small diameter part 13. Since the heating time at the maximum temperature is given to the member only when it passes through the small diameter part 13, the temperature history of heating and cooling is made steeper as compared with the conventional method. Since the strongest magnetic force is made to act on the small diameter part 13 and the shearing-deformation force is large, fineness of crystalline structure is promoted in the coil for induction-heating at a highest degree. In the portion other than the small diameter part 13, since the magnetic force to the metallic member is relatively weakened in comparison with the small diameter part 13, the fineness of the crystalline structure hardly progresses as compared with that in the small diameter part 13. In the metallic member to be worked, the progressing rate of the fineness is different between the case when the member passes through the small diameter part 13 and the case when the member passes through the other part and so, the metallic member having the hardness and the prescribed toughness can be obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
