| 摘要 |
<p>PURPOSE:To shorten treating time and to reduce distorsion by providing a high frequency induction heating mechanism for tempering an annular member shrincage fitted over a hardening jig under shrincage fitted state and a cooling mechanism for cooling the tempered annular member, and incorporating the tempering process in an automatic thermal treating line. CONSTITUTION:An annular member 1 is heated in an electric furnace or a high frequency induction heater to a predetermined hardening temperature, then a small diameter section 2a of a hardening jig 2 is inserted into a central hole 1a of a member 1 enlarged through thermal expansion. Then the member 1 is cooled quickly and subjected to hardening, thereafter it is shrincaged fitted over a small diameter section 2a of the jig 2 through shrincage of the central hole 1a of the member 1. A high frequency heating induction coil 3 is arranged at the outer circumference of the member 1, and the member 1 is heated to a predetermined tempering temperature through high frequency induction heating under shrincage fitted state. Then the coil 3 is moved from heating position and a cooling jacket 4 is arranged in order to eject cooling liquid to the member 1 and to cool the member 1. Tempered member 1 is removed from the jig 2 through a drawing means, then the member is hardened to produce a hardened product 1.</p> |
