Sharing the quality of knowledge related to tempered glass

Tempered glass is obtained by first cutting an ordinary annealed glass into a desired size, then heating it to a near softening point, and then performing rapid and uniform cooling. After tempering, the surface of the glass forms a uniform compressive stress, while the inside forms a tensile stress, which greatly improves the performance of the glass. The tensile strength is more than three times that of the latter, and the impact resistance is more than five times that of the latter.

It is also this feature that the stress characteristic is an important sign to identify true and false tempered glass, that is, tempered glass can see colored stripes on the edge of the glass through the polarizing plate, while black and white can be seen in the surface layer of the glass. Interphase spots. Polarizers can be found in camera lenses or glasses, and attention is paid to the adjustment of the light source during viewing, which makes it easier to observe.

There is a 3C certification mark on each tempered glass.

Self-destructive defect

The automatic explosion of tempered glass under the action of no direct mechanical external force is called self-explosion of tempered glass. According to industry experience, the self-explosion rate of ordinary tempered glass is about 1~3‰. Self-explosion is one of the inherent characteristics of tempered glass.

There are many reasons for expanding the self-explosion, and simply summarize the following:

Effect of glass quality defects

A. There are stones and impurities in the glass. Bubbles: Impurities in the glass are the weak points of the tempered glass, and also the stress concentration. In particular, if the stone is in the tensile stress zone of the tempered glass, it is an important factor leading to the cracking.

The stone is present in the glass and has a different coefficient of expansion than the glass body. The stress concentration in the crack region around the stone after the tempering is multiplied. When the coefficient of expansion of the stone is smaller than that of the glass, the tangential stress around the stone is in a tension state. Crack propagation that occurs with stones is highly prone to occur.

B. The glass contains nickel sulfide crystals.

The nickel sulfide inclusions are generally present as crystalline small spheres having a diameter of from 0.1 to 2 mm. The appearance is metallic, and these inclusions are Ni3S2, Ni7S6 and Ni-XS, where X=0-0.77. Only the Ni1-XS phase is the main cause of spontaneous smashing of tempered glass.