What is the tempering principle of tempered glass?How can ordinary glass be turned into tempered glass through specific processes?
The tempering principle of tempered glass is mainly to treat ordinary glass through specific processes to make it have higher strength and safety.
Usually, the physical tempering method is adopted. The process is as follows: heat ordinary glass to a temperature close to softening, generally around 600°C - 700°C. At this time, the glass is in a plastic state but has not yet softened and deformed. Then, cool both sides of the glass quickly and uniformly with high-speed airflow or liquid. Due to rapid cooling, the outside of the glass shrinks and hardens first, while the inside cools relatively slowly and is still in a high-temperature plastic state. As the inside gradually cools, it will generate tensile stress on the already hardened outside, and at the same time, the outside will generate compressive stress on the inside. In this way, a uniformly distributed stress structure is formed in the glass.
When tempered glass is impacted by an external force, the compressive stress on the surface first offsets part of the external force, thereby increasing the strength of the glass. Even if the glass is broken, the interaction of the tensile stress inside and the compressive stress on the surface causes the glass to break into small particles without sharp corners, reducing harm to the human body.
The chemical tempering method forms a compressive stress layer on the glass surface through ion exchange. Immerse the glass in a molten alkali metal salt solution, and small ions in the glass (such as sodium ions) exchange with large ions in the solution (such as potassium ions). Since the radius of large ions is larger than that of small ions, compressive stress is generated on the glass surface, thereby increasing the strength of the glass. This method is mainly suitable for the tempering treatment of thin glass.