Tempered glass is called float glass, which has undergone a special chemical and thermal processing, resulting in the strength of the glass and the resistance to sudden temperature changes significantly increased (more than 5 times). In addition, the glass becomes much safer for humans. This is reflected in the fact that the destruction of tempered glass shatters into many small blunt pieces, which safe for humans (usually the same broken glass on the dangerous shards). Tempered glass is produced in special furnaces of the glass sheets. The process of tempering glass occurs in the following order: first the glass is heated above the softening temperature and then rapidly cooled in an evenly applied to the entire surface of the glass air jets. The first cooling hardens the surface layers of glass and then the inner layers, where the cooling, there are residual compressive stresses.
These voltages and provide mechanical strength and heat resistance of the material. As a result of these actions change the physical characteristics of glass: much increased strength of the material in relation to external factors (mechanical and thermal). For example, the tensile strength of tempered glass in bending can reach 250 MPa. This is 5-7 times higher than normal float glass; material able to withstand sudden changes in temperatures from -70 C to 250 C. With a gradual increase in temperature to 1800 C glass preserves the integrity and physical characteristics. Due to this property tempered glass is widely used in a fire-glazing, tempered glass is stable for a large temperature difference inside and outside. This property of material value in our Siberian conditions, where the air temperature outside, For example in winter can fall below the mark – 40 C, while in the room she reaches the value + 30 C, the optical characteristics of the material stored at 99% even if the heat treatment being tinted in the mass glass; fracture tempered glass instantly and completely breaks down into small, almost safe, with mild-edged shards. However, it should be noted that tempered glass can not be subjected to various kinds machining, such as: drilling, cutting, edging, etc. All the necessary manipulations with glass needs to be done before hardening. Cutting glass under the right size, edging glass, as well as drilling technology openings must take place before the hardening process, since after quenching the glass should not be subjected to these procedures (otherwise the glass will break into many small pieces when machining). Because of its safety and high performance, tempered glass is widely used in the manufacture of products such as interior glass doors, glass partitions, and various architectural design.