The cause of self-explosion of tempered glass and the weathering of glass

What is the cause ofself-explosion of tempered glass? What causes the weathering of glass?

Glass is an ancient building material that has been around since ancient Egypt. With the common development of humansociety, the glass industry has created a variety of unique glass, which makesthe glass family continue to flourish, such as bulletproof glass, photoelectric glass, vacuum glass, etc., all glass play an irreplaceable role in theirrespective fields.

The cause of self-explosion of tempered glass

1. Glass quality defects

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

The stone is present in the glass and has adifferent coefficient of expansion than the glass body. The stressconcentration in the crack region around the stone after the tempering ismultiplied. When the coefficient of expansion of the stone is smaller than thatof 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 sulfidecrystals.

Nickel sulfide inclusions are generallypresent as crystalline small spheres having a diameter of from 0.1 to 2 mm. Theappearance is metallic, and these inclusions are Ni3S2, Ni7S6 and Ni-XS, whereX=0-0.77. Only the Ni1-XS phase is the main cause of spontaneous smashing oftempered glass.

C. The surface of the glass is scratched,blasted, deep-blasted, etc. due to improper processing or operation, which maycause stress concentration or self-explosion of tempered glass.

2. The stress distribution in the temperedglass is uneven and offset.

The temperature gradient generated by theglass in the direction of the thickness of the glass when heated or cooled isuneven and asymmetrical. The tempered products have a tendency toself-explosion, and some produce "wind burst" when chilled. Thetempered glass forms a self-explosion if the tensile stress zone is offset toone side of the article or offset to the surface.

3. The influence of the degree of tempering, the experiment proves that when the degree of tempering is increasedto 1 level/cm, the self-explosion number is 20%~25%. It can be seen that the greaterthe stress, the higher the degree of tempering and the greater theself-explosion.

The cause of glass weathering

Glass back alkali is also called glassweathering or mold. The effect of glass and atmosphere is called wind tilting.After weathering glass, there is a misty film on the surface, or a spot-like,fine-lined fuzzy weathering, sometimes irregular iridescence. When the weathering situation is serious, the surface of the glass forms hoarfrost, thuslosing transparency, and even the phenomenon of sticking between the flat glass sheets. Therefore, domestic weathering is also called moldy or mildew.

Most of the weathering occurs in theprocess of glass storage and transportation, especially in the case of temperature, high and poor ventilation. The glass with poor chemical stabilitycan also weather in the atmosphere and room temperature. Not only the flatglass is weathered, the bottle can , utensils, optical glass will produce weathering.

After the weathering of the glass, thequality of the decoration is affected. For example, when the coating is uneven,the film layer is peeled off, and the film layer is usually not suitable forsurface decoration with the weathered glass.

Related concepts

Tempered glass

Tempered glass/Reinforced glass is a safety glass. Tempered glass is actually a kind of prestressed glass. In order toincrease the strength of the glass, chemical or physical methods are usuallyused to form compressive stress on the surface of the glass. When the glass issubjected to external force, the surface stress is first offset, therebyimproving the bearing capacity and enhancing the resistance of the glassitself. Wind pressure, cold and heat, impact and so on.