Heat Soaked Glass

The vitreous contains nickel sulfide (NiS) particles, which do not grow rapidly during tempering cooling, but grow slowly during use, resulting in stress concentration and self-detonation of the glass.
HST tempered glass means that the tempered glass will in a heat soaked furnace, and the phase transition of nickel sulfide (NiS) in tempered glass will through the process of heating, when heat preservation and cooling, so that the stress inside the glass tends to balance, so as to greatly reduce the self-detonation rate of tempered glass.