How is toughened glass manufactured

The process is repeated several times until an isothermal state is achieved. This effect is reversed in the latter stages. The final glass produced can thus withstand stress on its surface. If the stress exceeds its strength, it will safely shatter into small fragments. Fully tempered glass is stronger compared to heat treated and the annealed glass. It can withstand high temperatures used in ovens and baking appliances.

Heat strengthened glass is relatively stronger than window glass but less so than fully treated glass. The difference arises as a result of residue stress effect on the glass surface and its edges.

Both will undergo the same deflection under the same load before shattering. The higher the thermal expansion of the glass and the lower its thermal conductivity, the higher will be the level of residue stresses, and as a result of this, the stronger will be the resulting glass.

When the salt dissolves, it is indicative of its separating into ions. The potassium ions are now free to replace sodium ions in the surface of the glass. This creates a tension inside and now the force required to break the glass has to be much greater more than the compressive forces. Hence, this method aims at strengthening the glass by chemical ion exchange. There are mainly five different types of toughened glass in existence.

Instead, it breaks into smaller granular pieces that are less likely to cause harm. This is why tempered glass is used in passenger vehicle windows, refrigerator trays, shower enclosures, microwave ovens, and other things we use on a regular basis.

Tempered glass is also much stronger than annealed glass. It undergoes a complex manufacturing process that toughens it both physically and thermally.

This results in compressive stress on the surface and improved bending strength of glass. Before toughening, the glass must be cut to size or pressed to shape. Toughening does not alter the basic characteristics of glass like light transmission and solar radiant heat properties of normal glass. It can neither be cut, nor altered. A safety glass, toughened glass is difficult to break but in the event of a breakage, disintegrates into small globules.

However, it is prone to very rare spontaneous breakage, a condition that occurs when the repeated heating and cooling cause the nickel sulfide stones to increase in size. First, the glass is carried by rollers and goes through the furnace. Here, three types of modes are used to heat the glass, viz. While the rollers help to conduct the heat, the coils enable radiation of heat.

This ensures that the glass is evenly heated on every side.