During actual engineering use, tempered glass may break or explode under normal conditions of use without visible external impact due to some special reasons.

The reasons for breaking or bursting are complex and can be roughly divided into three categories:

1. The reasons for the tempered glass itself, such as the phase transformation and expansion of the nickel sulfide stones in the tempered glass, the stress concentration caused by the hard stones, the excessive tangential stress around the elemental silicon impurities, etc., the breakage or explosion caused by these reasons is called " Self-destruct". In addition, external factors in the production process, such as excessive tempering, uneven stress of tempered glass, and poor glass edge processing, will make tempered glass with internal stones more likely to explode. Self-explosion caused by heterogeneous particles (such as nickel sulfide stones, elemental silicon particles, etc.) often has typical self-explosion cracks.

2. Improper design, installation or use. Such as the use of oversized tempered glass, the stress concentration of the glass caused by improper installation, the use of glass components made of multiple pieces of tempered glass or tempered glass and other glass, and the structure or use environment of the component makes the tempered glass suffer from long-term heat exchange. But it frequently undergoes large temperature differences, alternating hot and cold, and so on.

3. In many cases, it is the combined effect of the above two. In the actual engineering process, the comprehensive effect is more universal.

The above situation shows that removing the design, installation or improper use and other factors, the root cause of the self-explosion of tempered glass is determined by its own inherent characteristics, so the automatic explosion of tempered glass in a non-impact state cannot be completely avoided.

In order to reduce the hazards and losses caused by the self-explosion of tempered glass, the following measures can be taken to reduce the breaking or bursting of the above-mentioned tempered glass in the non-impact state:

a) Use original sheets with less nickel sulfide stones, particulate impurities and bubbles, that is, use high-quality processed flat glass sheets; moderate tempering to avoid excessive glass tempering stress, and ensure that the surface stress is as uniform as possible; improve the edge Processing quality; according to GB15763.4-2009 Appendix A, the tempered glass is subjected to secondary heat treatment (usually called detonation, homogenization or hot dip treatment); before the tempered glass leaves the factory, refer to GB/T30020-2013 ``Glass defect detection method _Photoelastic Scanning Method" scans the products, analyzes the types of defects at the stress concentration points, and takes corresponding measures for products with hidden dangers of self-explosion.

b) Design and use tempered glass of appropriate size, and ensure the accuracy of processing; ensure the quality of installation, avoid deformation of the tempered glass during the installation process; rationally design and use glass components with tempered glass to reduce thermal expansion and contraction The effect of thermal stress caused.