Tempered glass is now known to many: it is made shop windows, it is inserted into doors and cars, passenger cars and ships.
The wide dissemination of a special type of glass contribute to its unique qualities, which gives the material by using special technology.
Manufacturing tempered glass meansseveral stages through which the sheet material is plain. Main stage - hardening, which gives the glass strength exceeding similar characteristics conventional material several times. But this is not the only plus tempered glass. With its destruction does not form sharp fragments could cause injury, indicating that the security of the material for use in various fields: construction, automotive and other industries.
Preparation of glass and heating
Please carefully inspect the selected material- Inside the bubbles should not be outside - scratches and other defects. Any flaws will inevitably give rise to internal stresses leading to cracking. If necessary, the templates are cut blanks required form- with their edge grind on special (Facet) machines. All operations with workpieces (drilling, cutting, and other kinds of processing) is performed before tempering.
The next step - heating. It must be done in a uniform heating of the surface. The temperature and duration of heating are connected. With longer duration of the heating temperature should decrease, and vice versa. Placing a cold glass in the furnace at the initial stage causes the cooling, but then the temperature is quickly restored to its original value. After a short exposure in the thick, glass blowing is moved to the grates.
The heating time of the sheet to 6 mm in thickness to 620-650oS furnace is between 3 minutes and 40 seconds to 5 minutes (depending on the chemical composition of the material).
Cooling and control
Cooling material can be in different ways: using oil, air, various liquids. However, the method is considered the most effective air cooling. It is perpendicular to the sheet feed several air jets from nozzles which are arranged in staggered rows. Some manufacturers provide additional rotation of the blower lattice so that each air stream performs rotational movement.
Properly treated glass can withstand 1800oS, which allows its use in the manufacture of electric stoves and fireplaces.
After the glass has cooled, is conductedquality control. To determine the thickness using a micrometer, which perform measurements in 4 different points. Of course the product must be completely bestsvetnym- sorting is performed depending on the presence of defects (hairline, bubbles, midges and so on). To test the strength of a height of 0.8 m on the surface of dropping a metal ball weighing 800g (sheet thickness less than 5 mm). In this case the glass should crumble into pieces no larger than 3.2 cm.