| 摘要 |
<p>Method of heat-treating large castings, forgings, e.g. rolls by two-stage heating operations in parallel. Surface pre-heating up to AC1 is firstly effected by direct transmission, e.g. gas burners, radiation or plasma arc. Medium frequency induction heating is then used to heat roll to give depth to above AC3, prior to quenching. Method is cheaper than using two induction heating stages of different frequency.</p> |
