By shape
1. Tempered glass is divided into flat tempered glass and curved tempered glass according to its shape.
The thickness of the tempered glass is 3 to 25 mm, etc., and the thickness after the specific processing depends on the equipment and technology of each manufacturer. However, curved (ie, bent steel) tempered glass has a maximum arc limit for each thickness. That is, R R is usually referred to as a radius.
2. Tempered glass is divided into flat steel and curved steel according to its appearance.
3. Tempered glass is divided into: excellent products, qualified products according to its flatness. The tempered glass of superior grade is used for automobile windshield; the qualified product is used for architectural decoration.
By process
1. Physical tempered glass is also called quenched tempered glass. When the ordinary flat glass is heated in a heating furnace to a softening temperature (600 ° C) close to the glass, the internal stress is removed by its own deformation, and then the glass is removed from the heating furnace, and the high-pressure cold air is blown to the glass by a multi-head nozzle. The tempered glass can be obtained by rapidly and uniformly cooling the two sides to room temperature. This kind of glass is under internal tension and externally stressed. Once local damage occurs, stress is released and the glass is broken into numerous small pieces. These small pieces have no sharp edges and are not easy to injure people.
2. Chemically tempered glass increases the strength of the glass by changing the chemical composition of the surface of the glass, and is generally tempered by ion exchange. The method comprises the steps of: immersing a silicate glass containing an alkali metal ion in a molten lithium (Li+) salt, exchanging Na+ or K+ ions of the glass surface layer with Li+ ions, and forming a Li+ ion exchange layer on the surface, due to Li+ The expansion coefficient is smaller than Na+ and K+ ions, so that the outer layer shrinks less and the inner layer shrinks more during the cooling process. When cooled to normal temperature, the glass is also in the inner layer and the outer layer is under pressure. Similar to physical tempered glass.
According to the degree of tempering
Tempered glass is obtained by first cutting an ordinary annealed glass into a desired size, then heating it to a near softening point, and then performing rapid and uniform cooling. After tempering, the surface of the glass forms a uniform compressive stress, while the inside forms a tensile stress, which greatly improves the performance of the glass. The tensile strength is more than three times that of the latter, and the impact resistance is more than five times that of the latter.
It is also this feature that the stress characteristic becomes an important sign to distinguish true and false tempered glass, that is, tempered glass can see colored stripes on the edge of the glass through the polarizing plate, while black and white can be seen in the surface layer of the glass. Interphase spots. Polarizers can be found in camera lenses or glasses, and attention is paid to the adjustment of the light source during viewing, which makes it easier to observe.