Shipa Glass India Pvt Ltd - Glass Products - Heat-Soaked-Glass

• Shipa Heat Soaked Glass can be used in citical aplication areas to minimize (if not totally eliminate) the risk of spontaneous breakage.
  
  Nickel Sulphate (NiS) has been known to be the cause of spntaneous burst in tempered glass. During tempering the nickel sulphide is transformed to the high tempered a- phase (t>380C) has no time to retun to the ß- phase on quenching. With the passage of ime NiS slowly inverts to the low temperature ß- phase with the increase in volume of bout 4%. This volume expansion may cause glass breakage.
  
  The heat soak is a destructive treatment which heat the glass for several hours at about 290 C to speed up the a -NiS to ß - NiS transformation and consequently forces the contaminated glassess broken within the oven.

Heat Soaked Testing is not an absolute guarantee that the glass will not break spomtaneously due to NiS but it substaintially lowers the risk. Studies hav been concluded worldwide indicating the reliability of heat soak test to as high as 98.5%.