HST (heat soaked) tempered glass means that the tempered glass is placed in a heat soaked furnace, and the phase transition of nickel sulfide (NiS) in tempered glass is made through the process of heating, 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.
Why tempered glass self-detonation
The reason for self-detonation of tempered glass is that sulfur and nickel impurities are mixed in the glass manufacturing process, and nickel sulfide is generated at high temperature. There are two kinds of crystallization of nickel sulfide. At high temperature (t>380 ℃) α Phase and low temperature β Phase. Due to rapid cooling during tempering,α phase a has no time to change into β Phase. During using process, theαphase is slowly transformed into stable β Phase, accompanied by about 4% volume expansion, causes the self-explosion of tempered glass.
Benefits of tempered glass after heat soaked process
The function of homogenizing furnace is to make nickel sulfide αphase completely transformed into low-temperature stable β phase. In addition, the glass produced from the furnace can no longer self-detonation, effectively ensuring that the tempered glass does not to self-detonation.