The spontaneous explosion of tempered glass refers to the inner stress of tempered glass without any outside force caused tempered glass explosion. The major reason caused the spontaneous explosion is that the volume of NiS crystal increased in the crystal transition process or the hard silicon crystal expand, which made the compressive stress larger than tensile stress, destroy the balance between compressive stress and tensile stress, then caused the tempered glass broken.
Now the online inspection equipment in the float glass production line couldn’t detect out the micron-grade NiS crystal and hard silicon crystal, so the spontaneous explosion couldn’t be forecasted. The spontaneous explosion becomes the inherent properties or defect for the toughened glass.
The spontaneous explosion rate is the counted afterwards without any scientific basis, just have business value. The impurity substance in the raw materials which is used for glass production, could be calculated in general, so based on the large data, to infer the spontaneous explosion rate of tempered glass is reasonable according the quantity of impurity substance in the raw materials for glass.
According the statistical results for years, there maybe one NiS grain which could lead the toughened glass broken in the glass which the weight is around 4tons to 8tons. To average that there is on one NiS grain in 6tons glass, according that the normal glass size in curtain wall is 6mm thickness with 2600mm×1200mm, then every 1000 glass pieces is around 47tons, so there is 8 NiS grains in the 1000 glass pieces could lead the toughened glass broken, then we could get that the spontaneous explosion rate for this glass specifications is about 0.8%.
The thicker glass with larger size, the glass pieces will be less based on same weight raw materials. But the NiS and hard silicon is still that quantity, so the spontaneous explosion rate is high. If there is one tempered glass which weight is 6tons, it must be spontaneous explosion, of course there is no glass with so larger size.
Now in glass field, 0.5% spontaneous explosion rate for tempered glass is the defining standard to re-produce freely or not. Because the spontaneous explosion will occur in the production process, the followed deep process and moving process, so the 0.5% Spontaneous explosion rate is reasonable. Please note that the tempered glass with larger size have higher spontaneous explosion rate, so it’s better to assess singly and take other actions.
Post time: Aug-02-2022