Analysis of the problems of tempered glass in optics
1) The central part is gray. After some glass is tempered, the surface of the contact roller will appear gray. This situation will worsen the see-through performance of the glass, which usually occurs in the middle of the glass. There are two main reasons for this situation: ①The temperature of the rollers in the heating furnace is too high. This situation mostly occurs in the first two furnaces of glass that have just been used in the tempering furnace. In this case, you can appropriately increase the pressure of the heat balance blowing, or reduce the empty furnace time to ensure continuous glass production; ②The amount of SO gas used is too large. If SO, as a protective gas for glass, is used too much or too frequently, it will cause the glass surface to appear gray.2) The problem of excessive stress spots. The tempered glass produced by the physical tempering method will have the phenomenon of stress spots, which is based on the production principle of physical tempering The decision is also unavoidable. Sometimes this phenomenon is also used to identify whether the glass is tempered glass, but when the stress spot is too heavy, especially when observed under certain light conditions, this phenomenon becomes a problem of appearance quality defects. Excessive stress spots are usually caused by the following three reasons: ① Excessive wind pressure during the quenching process. This high-pressure, high-speed airflow blowing on the near-softened hot glass will aggravate the stress spots of the tempered glass. This situation can be avoided by adjusting the parameters of the wind pressure; ②When the glass has just entered the cooling chamber from the heating chamber and has begun to blow and cool, the swing of the wind grid or the rotation of the roller table will be stopped, resulting in wind grid The mouth only blows to one part of the glass. When this happens, the swing of the air grille or the rotation of the roller table should be restored in time with the synchronization of the blowing; ③When the air is blown and cooled in the cooling room, the distance between the nozzle of the air grille and the glass is too close. When this happens, the height of the wind grid can be appropriately increased by adjusting the parameters without affecting the particle size of the glass and other quality requirements. 3) The iridescence phenomenon of tempered glass The iridescence phenomenon of tempered glass is an optical phenomenon. During the forming process of float glass, harmful substances such as oxygen and water enter the tin bath, which will oxidize and react with tin at high temperature to form SnO and SnO. Among them, Sn and Sn penetrate into the lower surface of the float glass through the tin liquid. An extremely thin tin-containing layer rich in Sn and Sn is formed. When this kind of float glass with high tin content is tempered, the SnO on the surface of the glass is oxidized to SnO after the glass is heated in the tempering furnace, and its volume increases, resulting in tiny wrinkles on the glass surface. Under the irradiation of light, interference of light occurs. Therefore, the iridescent phenomenon of tempered glass is not only related to the quality of the float glass as the original glass, but also related to the tempering process. In the glass tempering production, in addition to selecting high-quality float glass as the original sheet, the heating temperature and heating time parameters of the tempering furnace must be adjusted to adapt to the actual conditions of different original sheets of glass.