BOBINA DI RISCALDAMENTO PER INDUZIONE PER TRATTARE TERMICAMENTE TUBI METALLICI.

摘要

An induction heating coil for heat-treating a metallic tube by producing compressive residual stress in the outer surface of the metallic tube. The induction heating coil is adapted to be spaced from and surround the metallic tube and comprises a plurality of donut-shaped hollow electric conductor members for inductively heating the metallic tube and a plurality of donut-shaped hollow water tubes including a large number of nozzles for spouting cooling water toward the metallic tube so as to form a uniform water film thereon with the nozzles being inclined with respect to the longitudinal direction of the metallic tube.