| 摘要 |
PURPOSE:To remarkably improve the workability of a scroll member made of an iron alloy by softening entirely or locally the spiral and flat parts by annealing, decarburization or other method. CONSTITUTION:A scroll member 1 made of an iron alloy is attached to a chuck 6 on a turntable 5. A preheating coil 7 is moved forward with a driving device 8 and while being rotated with the turntable 5, the member 1 is preheated with an induced current from a power source 9. When the whole member 1 reaches the preheating temp., a driving device 11 and the turntable 5 are moved in synchronism with each other, and while a heating coil 10 is being moved along the spiral part, a high frequency induced current is supplied from a power source 12 to heat the surfaces 2 of the lapped side walls and the surface 3 of the flat plate. |
