| 摘要 |
PURPOSE:To obtain springs which are used for a shadow mask and are excellent in terms of both the cost and the work efficiency by putting springs into a case made of a heat-resisting member and having a good airing, and subjecting the springs to heat treatment within a set temperature range in an atmosphere of air. CONSTITUTION:When springs 2 are put into a heat-resisting case 1, which is prepared from a punch plate or a network member and has a good airing, and are subjected to heat treatment within the temperature range of 400-440 deg.C in an atmosphere of air, they are oxidized to an extremely small degree. By the means mentioned above, cost reduction of the thermal treatment of the springs 2 is enabled since the springs 2 can be treated in air. In addition, the case 1 is simple and light, and provides good work efficiency. When a continuous-mesh- belt furnace is used as a furnace for the above heat treatment, mass production is enabled since the load can be reduced because of the small weight of the case 1. Besides, any furnace used only for the heat treatment of the springs 2 becomes unnecessary. |
