| 摘要 |
<p>PROBLEM TO BE SOLVED: To uniformize the depth of a hardened layer when an inner surface of a tubular work is quenched, and resultantly, eliminate a problem on strength and prevent distortion. SOLUTION: A tubular work inner surface heater coil for heating side surface parts WT1 of groove parts WT in an inner surface of a triport cup W as a tubular work, is equipped with three heating conductor parts 100A, 100B, 100C confronting the side surface parts WT1 or surfaces to be heated, and the heating conductor parts 100A, 100B, 100C have, on their upper-side end parts, projection parts 111A, 111B, 111C, respectively, projecting to the side of the side surface parts WT1.</p> |
