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History of tempered glass

History of tempered glass
History of tempered glass

The development of tempered glass, also called physical hardening can be traced back to the middle of the 17 th century.
The method of annealing comprises heating the glass up to a softening temperature and its immediate placement in a water bath at a relatively low temperature in order to increase its resilience to external influences. This is a method of early hardening liquid.
In 1875. German Frederick Siemens receives first patent, and in Massachusetts in 1876. Geovge E. Rogens the method for hardening on the glass and street lamp. In the same year in New Jersey, Hugho'heill receive a patent.
The history of tempered glass in China began in 1955. At this time in Shan Hai, Yaohua Glass Factory began trial production during 1965. placed first tempered glass on the market.
In 1970. technology tempering the glass gets popularity worldwide. Tempered glass began to be applied in many industries, particularly in the automotive and construction, where there are conditions for the fastest economic growth.

Tempered glass is done using a specially heated furnaces that it heated under a constant temperature of about 700 ° C. When the glass out of the furnace is cooled rapidly, it puts the glass surface in a state of compression, while in the middle and left voltage.


Annealing method:

Tempering of glass is performed by uniformly heating to 700 ° C temperature with immediate cooling. Glass first passes through the furnace-driven rollers, where it is heated in three modes - conduction, convection and radiation. Rolls conduct heat and the coils help in broadcasting and. The effect of convection caused by air exiting through the nozzles, thus circulates heat evenly and heat from all sides. Then the hot glass is subjected to rapid cooling.

After tempering, the mechanical strength of tempered glass is 4-5 times higher than that of ordinary glass. Tempered glass has a higher thermal stability and can withstand high temperatures up to 250 ° C, is practically considered to be unbreakable. It is hard to break, but even in this case it breaks into small relatively harmless particles.
Hardening does not change the basic characteristics of glass as transmission of light, sun and heat, ie possess the qualities of normal glass. The surface of the glass after heat treatment has a high resistance to damage, then you can not be cut or altered.

One problem that can occur in the process of tempering glass is broken spontaneously for no apparent reason.


qualities of tempered glass

Need for annealing of glass

Toughening increases the tensile strength, thermal stability and safety of normal glass. It also increases the capacity of absorption of heat. Due to these properties, the tempered glass is preferable in use, because these parameters are important considerations.


characteristic fracture
Heat resistance:

Uneven heating from direct sunlight causes a sharp expansion and contraction of the glass, which can lead to breakage. When the temperature difference is below 32 ° C, the risk of thermal breakage of glass is low, but when the difference is increased, the risk increases significantly.

thermal breakage

Thermal breakage starts from the edge and perpendicular to it.

Application of tempered glass:

Tempered glass is specially designed for use in areas where there is high risk of fracture because it is harder to break or scratch. There is a wide scope for its use in the construction industry. Application is in the construction of exterior and interior walls, showroom shelves and shelves, shower cabins, shower screens, doors, awnings, roofs and much more.