Analyzing the stress characteristics of glass as a function of cooling rate when applying air and mist for rapid cooling of glass heated to high temperatures

When glass is heated to the softening point of 600–700 ℃ and then cooled rapidly, compressive stress is generated on the glass surface, and residual tensile stress inside. The compressive stress on the glass surface inhibits the growth of cracks on the surface, which strengthens it. In general, rapid cooling of a glass surface is performed by air, and the residual stress on the glass surface varies depending on the process conditions. In this study, a cooling system for glass is proposed by a water mist spraying system applied to glass that has reached its softening point. Initially, to verify the feasibility of the experiment, a numerical analysis of the cooling characteristics is performed. Then, the mist cooling system is designed to conduct cooling experiments by mist and air. The mist is kept constant, and the residual stress and fragment characteristics are analyzed by varying the air speed to determine the possibility of strengthening the glass. It is confirmed that the cooling effect is enhanced when using the mist, even at relatively low air inflow speeds, and that the effect of the mist is weakened when the air velocity exceeds a certain level.