| 摘要 |
PURPOSE:To prevent the occurrence of a crack in a glass structure by applying heat-melting treatment to the border of a neck and a funnel of the glass structure with a heat insulating plate placed in the funnel and putting the glass structure in an electric furnace to remove strain. CONSTITUTION:A neck 1 and a funnel 2 are welded by heating and melting their mating portions and then removing the strain remaining around the border to form a glass structure used for color cathode-ray tube or the like. The structure is put into an electric furnace 3 with the neck 1 facing the bottom and a heat insulating plate 4 placed in the funnel 2 above the electric furnace 3, to remove strain by heating. Temperature variation near the border during heating can be minimized by the effect of the heat insulating plate 4, enabling high quality strain relieving while preventing the occurrence of a crack in the glass structure.
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