Introduction to tempered glass
Tempered glass is also known as tempered glass. It uses a physical or chemical method to form a compressive stress layer on the surface of the glass. The glass itself has a high compressive strength and does not cause damage. When the glass is subjected to an external force, the pressure layer can offset part of the tensile stress to avoid the chipping of the glass. Although the inside of the tempered glass is in a state of large tensile stress, the interior of the glass has no defects and does not cause damage. In order to achieve the purpose of increasing the strength of the glass.
Tempered glass is a secondary processing product of flat glass. The processing of tempered glass can be divided into physical tempering method and chemical tempering method.
Physical tempered glass is also known as hardened tempered glass. It is to heat the ordinary flat glass in the heating furnace to the softening temperature (600 ° C) of the glass, to eliminate the internal stress by its own deformation, then remove the glass from the heating furnace, and then use the multi-head nozzle to blow the high-pressure cold air to the glass. The tempered glass can be obtained by rapidly and uniformly cooling the two sides to room temperature. This kind of glass is under 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.
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 that of 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.
The strength of tempered glass is high, its compressive strength can reach above 125MPa, 4~5 times larger than ordinary glass; the impact strength is also very high. When measured by steel ball method, 0.8kg steel ball falls from 1.2m height, glass can be Keep it in good condition.
The elasticity of tempered glass is much larger than that of ordinary glass. A piece of tempered glass of 1200mm×350mm×6mm can be bent to a depth of 100mm after being subjected to force. When the external force is removed, it can still be restored to its original shape. A few millimeters.
The thermal stability is good. When it is subjected to rapid cooling and rapid heat, it is not easy to cause cracking, which is another feature of tempered glass. This is because the compressive stress of the tempered glass can offset some of the tensile stress caused by the rapid cooling. The tempered glass has thermal shock resistance and the maximum safe working temperature is 288 °C, which can withstand the temperature difference of 204 °C.
Because tempered glass has good mechanical properties and thermal stability, it is widely used in construction engineering, transportation and other fields. Flat tempered glass is often used as doors and windows, partition walls, curtain walls and window windows, furniture, etc. of buildings. Curved glass is often used in automobiles, trains and airplanes.
It should be noted that the tempered glass can not be cut and ground, and the corners can not be crushed. It needs to be selected according to the ready-made size specifications or the specific design drawings can be customized. The glass used for the large-area glass curtain wall should be controlled on the tempering. The semi-tempered glass should be selected, that is, the stress should not be too large to avoid self-explosion due to the vibration caused by the wind load.
Depending on the original glass used, it can be made into ordinary tempered glass, endothermic tempered glass, tempered tempered glass, tempered insulating glass, and the like.
Most of the tempered glass currently on the market is used in the decorative industry.
Its products are mainly reinforced film bonding and glass surface, so that it can enhance the explosion-proof effect.
If the glass is damaged due to external force, the glass fragments will adhere tightly to the high-strength, high-strength polymer film, and will not fall off, and the safety performance is high.
There are countless varieties of reinforced membranes.
A typical paint-enhanced film, commonly known as "photo film", uses ink-coating technology to make the painted pattern appear on the film, thus achieving the effect of the stained glass, and the environmental performance of the product is low.
There are also color film made by printing composite technology. There are many such products on the market, and the varieties of the products are different from each manufacturer. The typical "Diwei film" "Midi film" "dia film" Etc., its product characteristics are better than "photo film", the substrate is more environmentally friendly PET, environmental protection and safety performance
Both are ideal, and this product is currently used in tempered glass production.
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