China glass factory supply 12mm tempered glass price for stair railing

Tempered glass is obtained by first cutting the ordinary annealed glass into the required size and then heating it to about 700 degrees near the softening point, and then performing rapid and uniform cooling (usually 5-6MM glass is heated at 700 °C for 240 seconds). Cool down for about 150 seconds. 8-10MM glass is heated at 700 °C for about 500 seconds, and the temperature is lowered by about 300 seconds. In short, depending on the thickness of the glass, the time for heating and cooling is different. After the tempering treatment, the surface of the glass forms a uniform compressive stress, while the inside forms a tensile stress, which improves the bending and impact strength of the glass, and its strength is about four times that of the ordinary annealed glass. The tempered glass that has been tempered can no longer be processed or damaged by any cutting, grinding, etc., otherwise it will “break the bones” due to the damage of uniform compressive stress.

Tempered Glass Features:
1. Safety: if breakage occurs the glass breaks up into small, cubical fragements, which are not threatening to human.
2. Stronger resistance to thermal breakage than annealed or heat strengthened glass 
3. 4-5 times stronger than annealed glass of the same thickness. 
4. It withstands abrupt temperature change of 220°C. 
5. Sizes are produced per customer request, once tempered, cannot be cut down