Solution to self explosion of tempered glass

The stress distribution in tempered glass is that the two surfaces of the tempered glass are under compressive stress, while the core layer is under tensile stress. The stress distribution in the thickness of the glass is similar to a parabolic curve. The midpoint of the glass thickness is the vertex of the parabola, where the tensile stress is high; There is compressive stress near the two surfaces of the glass on both sides; The stress surface is approximately located at one-third of the thickness. By analyzing the physical process of tempering and rapid cooling, it is known that there is a rough proportional relationship between the surface tension and the internal tensile stress of tempered glass, that is, the tensile stress is 1/2 to 1/3 of the compressive stress.

Domestic manufacturers generally set the surface tension of tempered glass at around 100MPa, but the actual situation may be higher. The tensile stress of tempered glass itself is about 32MPa to 46MPa, and the tensile strength of glass is 59MPa to 62MPa. As long as the tension generated by the expansion of nickel sulfide is 30MPa, it will cause self explosion. If the surface stress is reduced, it will correspondingly reduce the inherent tensile stress of tempered glass, thereby helping to reduce the occurrence of self explosion.

The surface stress range of tempered glass specified in the American standard ASTMC1048 is greater than 69MPa; Half tempered (heat strengthened) glass has a strength range of 24MPa to 52MPa. The standard BG17841 for curtain wall glass specifies a semi tempered steel stress range of 24<; δ≤69MPa。 The new standard GB15763 has been implemented. 2-2005 "Building Safety Glass Part 2: Tempered Glass" requires that its surface stress should not be less than 90MPa. This is 5 MPa lower than the 95 MPa specified in the old standard, which is beneficial for reducing self explosion.