| 摘要 |
PROBLEM TO BE SOLVED: To reduce the variation of the effect in heat treatment for improving the characteristics of the material of a piston stock. SOLUTION: Body members 162 after casting or forging are stored into a plurality of cylindrical bodies 216 in series so as to be coaxial. The cylindrical bodies 216 have holes 218 almost uniformly all on all fronts. The plurality of cylindrical bodies 216 are stored into a vessel having holes on all fronts in a state in which the axes are made parallel. They are charged to the inside of a heating furnace inclusive of the vessel, and, after heat treatment, lifting is performed by a draining apparatus serving also as a lifting apparatus, and they are dipped into a water tank stored with cool water inclusive of the vessel and rapidly cooled. After that, the vessel is taken up from the cool water, and before proceeding to the following aging treating stage, draining is performed. At first, the cylindrical bodies 216 are held in postures in which their aces are made horizontal, and water in the bottomed cylindrical part 170 is nearly exhausted. Subsequently, the cylindrical bodies 216 are rotated by a fixed angle per time in both the forward and backward directions around a straight line parallel to the aces, and also, they are tilted by small angles per time in two directions, by which water in the recessed part of a sump inclusive of the inside of the bottomed cylindrical part 170 can perfectly be exhausted.
|
