Physical tempering involves heating glass to a suitable temperature and then rapidly cooling it. This causes the glass surface to contract sharply, creating compressive stress. The inner layer of the glass cools more slowly and doesn't have time to contract, resulting in tensile stress, thus increasing the glass's strength.

　　The process of making tempered glass is actually quite simple. It mainly involves cutting annealed glass to the required size, then reheating it. When the temperature reaches the melting point of the glass, rapid and even cooling is performed to obtain tempered glass.

　　First, ordinary glass is heated until it reaches its softening temperature; then, the internal stress is relieved through its own deformation, and the glass is removed from the heating furnace; finally, high-pressure cold air is sprayed onto both sides of the glass using multiple nozzles, allowing it to cool rapidly and evenly to room temperature, producing tempered glass.

　　(1) Ordinary glass (Na2SiOCaSiOSiO2 or Na2O·CaO·6SiO2). (2) Quartz glass (glass made from pure quartz as the main raw material, the composition is only SiO2). (3) Tempered glass (same composition as ordinary glass). (4) Potassium glass (K2O, CaO, SiO2). (5) Borosilicate glass (SiOB2O3).

　　Step 6: The heated glass enters the wind baffle for rapid cooling. The heated glass is subjected to high-pressure air jets from different angles for a few seconds or minutes. Rapid cooling causes the outer surface of the glass to cool and contract faster than the center, giving the tempered glass its strength, transforming it into tempered glass. Step 7: Packaging, storage, and delivery.

　　There are two methods for producing tempered glass: one is to process ordinary flat glass or float glass under specific process conditions using a quenching method or air-quenching method.