| 摘要 |
<p>569,005. Electric induction heating. RADIO CORPORATION OF AMERICA. Oct. 21, 1942, No. 14784. Convention date, Dec. 5, 1941. [Class 39 (iii)] Metals are hardened by heating the surface by high frequency induction to a predetermined temperature substantially simultaneously and to a very small depth, and then quenching the heated layer by conduction through the backing layer. A high frequency generator 1 supplies current to an inductor ring 5 through a transformer 3 which may be a coil of concentric transmission line the inner conductor forming the primary. The ring 5 may be a water cooled tube and is shown applied to the cylinder bore 9 of an engine block 7, which is mounted on a platform 11 moved vertically by gearing rotated by a motor 23. The frequency may be 100 kilocycles, the ring 5 may be #inch thick, and power may be delivered to the work for .075 sec. or at the rate of 5K.W. per sq. cm. The block 7 may be moved at about 1¢ inches per second. The cylinder walls are thereby heated to 950 ‹C. to a depth of 0.02 inch. Heat is dissipated into the metal backing the heated skin at about the same rate as that at which it is applied. If the metal to be hardened is thin, it may be backed temporarily by Wood's metal or solder. The method may be applied to articles such as gear wheels or shafts by means of an external inductor ring. The method may be applied to ferrous and other metals, and to the annealing of metals, e.g., brass. The ring 5 need not be movable.</p> |
