Question

Name three types of heat modified glass, provide their relative strengths, and an application in which each is generally used. For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac).

Answer 1

a) annealed glass: glass produced without internal stresses without internal stresses imparted by heat treatment that is rapid cooling or by heat strengthening. Glass is treated with heat in order to change it's properties by annealing. But annealed gas tend to break in to longer, jaggered shards which can significant injury. It is generally used when strength or safety are not concerns but cost is. Annealed glass is the most common glass used in windows, other application are table tops, cabinet doors, shower door and bathroom areas.

b) Tempered glass: it is s type of safety glass process by controlled thermal or chemical treatments to increase its strength compared with normal glass.tempered glass had a minimum surface compression of 10,000 pound-per-squre inch and minimum edge compression of 9700 psi, according to ASTm C1048. This makes it about four times stronger than annealed glass.its main application is windscreen or wind shield other applications are balcony doors, facades, exhibition areas and displays,counter tops, furniture.

c) heat strengthened glass: in the production glass is heated to a uniform temperature 650C to 700C in an electrically heated horizontal furnace. HS glass provides the necessary resistance to thermal stress associated with high performance glazing materials such as tinted glass. HS glass differs from tempered glass in surface compression, it's mechanical strength is about 1.6-2 times that of annealed glass.HS glass has outstanding thermal stability, it's flatness and light transmission is close to that if annealed glass and much better than that of tempered glass.This glass is typically specified when additional strength needed to resist wind pressure, thermal stresses or both and the additional strength or safety break pattern of fully tempered glass is not required.HS glass continue to gain popularity and us often the choice of the design professionals for vertical vision spandrel areas and for laminated sloped glazing.HS has less opticcal distortions so it can be used in places where high optical quality is required. It can also used in general glazing where additional strength or resistance to mechanical /thermal loading caused by certain tinted or coated glass.