Causes of tempered glass self-explosion
Tempered glass self-explosion can be described as the phenomenon which tempered glass automatically breaks without direct external action. Tempered glass self-explosion can occur during tempering processing, storage, transportation, installation, and use.
Self-explosion can be divided into two types according to different causes:
One: Self-explosion caused by visible defects in the glass, such as stones, sand, bubbles, inclusions, gaps, scratches, and edge bursts;
Two: Self-explosion caused by the expansion of nickel sulfide impurities in the glass.
These are two different types of self-explosion, which should be classified, treated differently, and handled and processed in different ways. The former is generally visible and relatively easy to detect, so it is controllable in production. The latter is mainly caused by the expansion of tiny nickel sulfide particles in the glass, which cannot be visually inspected, so it is uncontrollable.
In practical operation and processing, the former can generally be removed before installation, while the latter continues to exist because it cannot be inspected, becoming the main factor for the self-explosion of tempered glass in use. It is difficult to replace nickel sulfide after self-explosion, and the processing cost is high. At the same time, it will be accompanied by large quality complaints and economic losses, causing dissatisfaction among owners and even more serious other consequences.
The expansion of nickel sulfide inside tempered glass is the main reason for the self-explosion of tempered glass. After the glass is tempered, compressive stress is formed on the surface layer. The internal core layer is tensile stress, and the compressive stress and tensile stress together form a balanced body.
Glass itself is a brittle material, which is resistant to pressure but not to tension, so most of the glass breakage is caused by tensile stress. When the nickel sulfide crystals in the tempered glass undergo a phase change, their volume expands. The expansion of nickel sulfide in the tensile stress layer of the glass core causes greater tensile stress inside the tempered glass. When the tensile stress exceeds the limit that the glass itself can withstand, it will cause the tempered glass to self-explode.
