The Heat Treated Tempered Glass Is Fractured Into Small Relatively Harmless Pieces

The heat treated tempered glass is fractured into small relatively harmless pieces by the tensile forces released from the glass center core and this phenomenon of breaking glass into small particle is called dicing. This cases the center of the glass to be hotter than the surface. As the center cools it forces the surfaces and edges into compression. Therefore such glasses can be Brocken only after overcoming this compressed extra surface. The basic objective of heat treatment process is to create an initial condition of surface and edge compression. This condition is achieved by first heating the safety glass, then cooling the surface rapidly. Over the years use of glass has increased tremendously. Modern structural design considerations, aesthetic tastes, energy saving and comfort consciousness demands glasses having increased strength, safety and thermal performances. This situation demands increased use of heat treated glass. The only physical properties that changed are improved flexural and tensile strength, and improved resistance to thermal stress and thermal shock. Heat treatment changes the break pattern of fire resistant glass. Fully tempered glass disintegrates into relatively small harmless pieces. The colour, solar properties, chemical compositions, hardness, specific gravity, coefficient of thermal expansion, softening point, thermal conductivity and stiffness remain unchanged after heat treatment. Upon withdrawal of hot building glass from the tempering furnace, it is rapidly cooled by blowing carefully controlled air flow from fixed or reciprocating or rotating blast nozzles uniformly onto both surfaces of glass simultaneously. Annealed float glass is cut into the required final size, the edges either seamed or polished and washed. There are two principle manufacturing method for heat treatment. One process heat treat it in a horizontal position while the second method moves the glass through the furnace in a vertical position with each light held by metal tongs. Source: glasszng.com/blog