| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a heat treatment apparatus for crank shaft with which the residual stress at hardened portion in the tip part of a pin part in the crank shaft is released and also, toughness at the hardened portion is improved, thereby so as to prevent crack from being caused at the hardened position of the tip part. <P>SOLUTION: The heat treatment apparatus for reheating the top parts of the pin parts P1-P4 after applying the hardening to the pin parts P1-P4 and journal parts J1-J5 in the crank shaft W, includes a coil 10 constituted in a spiral shape disposed on the same axis as the crank shaft W, and the reheating for releasing the residual stress at the hardened positions of the top parts of the pin parts P1-P4, is performed to the top parts of the pin parts P1-P4 of the crank shaft W after hardening by using this coil 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
