| 摘要 |
<p>979,069. Induction heating apparatus. REGIE NATIONAL DES USINES RENAULT. May 12, 1961 [May 14, 1960], No. 17470/61. Heading H5H. A process for the surface treatment of steel pinions by induction heating in two successive stages comprises the steps of applying low frequency heating at a frequency between 50 c.p.s. and 1500 c.p.s., and applying high frequency heating at a frequency between 50 kc./s. and 1.5 Mc./s. at a wattage of between 1-10 kw./s. sq. cm. of the surface being heated and for a time between 0.01-1 second. Finally the pinion is quenched by spraying. The pinion is held stationary during the two stages of heating and the changeover from low frequency to high frequency heating is effected in a period be tween 0.01-1 second. As shown, the pinion 6 is arranged at the centre of a high frequency inductor 2 which is supported by an insulating casing 12 enclosing a water chamber 7. Under the casing 12 is arranged a low frequency inductor comprising a coil 1 with a ferromagnetic circuit consisting of a yoke 3. The high frequency inductor 2 may be hollow for the passage of a cooling fluid. During the low frequency heating, the tips of the teeth 11 of the pinion may be cooled by a current of cold gas.</p> |
