What are the construction principles and raw materials of tempered glass?
Any of the above factors are closely related to the heating and cooling conditions of glass. When the glass is uniformly heated to the tempering temperature, it suddenly cools down. Because of the different cooling rate of the inner and outer layers, the surface layer cools and contracts rapidly, while the inner layer cools and contracts slowly. As a result, the inner layer is subjected to compressive compressive stress and the surface layer is subjected to tensile stress. As the glass continues to cool, the surface has hardened and stopped shrinking, while the inner layer is still cooled and contracted until the room temperature is reached. In this way, the surface layer is compressed by the compression of the inner layer, and the inner layer forms tensile stress and is permanently retained in the tempered glass. Because the glass is strong and weak tensile compressive brittle material, when the glass is broken more than tensile strength, so the size and distribution form of stress is the main factor influencing the strength of glass and crack. In another case, when the glass is cooled in a plastic state, whether it is uneven heating or uneven cooling, as long as there is a temperature difference on the same piece of glass, there will be different shrinkage. At room temperature, the higher the temperature, the greater the cooling, and the greater the shrinkage, the shorter the glass. On the contrary, the lower the temperature is, the less the cooling, the smaller the shrinkage, and the longer the glass. If a piece of glass is short of each piece, the board must be warped. In this way, it is not difficult to understand why glass is deformed and how to prevent deformation.
Tempered glass is the two processing product of flat glass. The processing of toughened glass can be divided into physical toughening method and chemical toughening method. Physical toughened glass is also called tempered tempered glass. It is the ordinary flat glass in heating furnace heated to the softening temperature close to the glass (600 DEG C), the internal stress of the self deformation is eliminated, and then removed from the glass furnace, with long nozzle high pressure cold air blowing glass on both sides, the rapid and uniform cooling to room temperature, well tempered glass can be made. This kind of glass in the internal and external tension compression stress state, once the local damage occurs, the stress release, the glass is broken into small pieces, these small pieces no sharp edges, not easy to hurt. In the production of tempered glass, the most influential factor on the quality of the product is how to make the glass form a larger and uniform internal stress. But the greatest impact on yield is how to prevent cracking and deformation.
Tempered glass, also called toughened glass, is a kind of prestressed glass. It uses physical or chemical methods to form a compressive stress layer on the surface of glass. The glass itself has a higher compressive strength and will not cause damage. When the glass is subjected to external force, the pressure layer may be part of the tensile stress offset, avoid broken glass, although tempered glass is in large internal stress state, but the glass no internal defects, without causing damage, so as to achieve the purpose of improving the strength of glass. It is well known that microcracks on the surface of materials are the main causes of material rupture. Because the microcrack will expand gradually under the action of tension, and finally crack along the crack. And because of the large compressive stress on the surface of the glass, the microcracks on the glass surface become more fine and even heal under the action of extrusion".
