Quality and safety of tempered glass

Tempered glass possesses high strength and safe breakage characteristics due to the uniform compressive stress on its surface. However, its internal stress structure also presents unique quality control requirements and a risk of spontaneous breakage.

 

1. Stress Characteristics and Quality Identification
Temperature glass, after rapid quenching, develops a typical stress distribution of "surface compressive stress - internal tensile stress," enabling it to achieve a bending strength 3-5 times that of annealed glass.

This stress structure not only provides reinforcement but is also an important characteristic for identifying tempered glass:

Colored stripes (stress stripes) are visible at the edges when observed under polarized light.

A black and white speckled structure is visible on the glass surface.

These stress interference phenomena can be observed using a polarizing microscope or a polarizer in a photographic lens, which are common methods for identifying tempered glass.

 

2. Spontaneous Breakage of Tempered Glass

The sudden breakage of tempered glass without external force is called spontaneous breakage. Industry experience shows that the spontaneous breakage rate of ordinary tempered glass is approximately 1–3‰, which is one of the inherent characteristics of tempered glass.