Tempered glass is annealed glass through high temperature and quenching, the surface layer forms strong compressive stress, so that the mechanical strength of the glass increases several times, that is, tempered glass. The surface stress of tempered glass is: 69~168 Mpa. It is characterized by the fact that it is broken into small obtuse particles after rupture, which will not cause major harm to the human body. The strength is 4 times or more than that of ordinary glass. It has good thermal stability, and the temperature difference that ordinary glass tempering can withstand is about 180°C. The disadvantage of tempered glass is that it is easy to self-explode.

Semi-tempered glass, also known as heat-enhanced glass, is annealed glass through high temperature and quenching, the surface layer forms a compressive stress of less than 69 MPa, so that the mechanical strength of the glass increases several times, that is, semi-tempered glass. The surface stress of semi-tempered glass is: 24~69 Mpa. After crushing, it is the same as ordinary glass, and the product feature is that the strength of semi-tempered glass is more than 2 times that of annealed glass. Safety: When broken, the fragments are radial, and each fragment extends to the edge, which is not easy to fall off, which is safer, but does not belong to safety glass. Deflection: The disturbance degree of semi-tempered glass is smaller than that of tempered glass and larger than that of annealed glass. Thermal stability: The thermal stability is also significantly better than that of annealed glass, and the temperature difference that ordinary glass can withstand after semi-tempering treatment is about 75 °C. Semi-tempered glass will not self-detonate.

Note: Due to the relatively high temperature of high-temperature resistant glass products, the products are generally semi-tempered, which cannot be fully tempered, and the tempering only enhances the compressive strength and heat stability of the glass.

The chemical stability of glass refers to the fact that the glass will be eroded by the surrounding medium (such as atmosphere, water, acid, alkali, salts and other chemicals) during use, and the ability of glass to withstand this erosion is called the chemical stability of glass. The chemical stability of glass is an important property of special glass, and it is also one of the important indicators to measure the quality of glass products. Glass for various purposes requires a certain degree of chemical stability.