Every piece of clear tempered glass is at risk of self-explosio
shock! Every piece of clear tempered glass is at risk of self-explosion, and so is yours...
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Can clear tempered glass explode? Maybe many people will feel unfamiliar. In recent years, the shower room has gradually been favored by consumers due to its small footprint and other advantages, but it is disturbing that the clear tempered glass of the shower room has the risk of self-explosion, and personal safety will be threatened if it is not careful.
The automatic explosion of clear tempered glass without direct mechanical external force is called self-explosion of clear tempered glass. According to industry experience, the self-explosion rate of ordinary clear tempered glass is about 1~3‰. Self-explosion is one of the inherent characteristics of clear tempered glass.
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So, what is the formation principle of clear tempered glass? Why blew up? How to prevent self-destruction? The following will answer each of them one by one.
What is clear tempered glass?
tempered safety glass, also known as tempered safety glass, is a glass with compressive stress on the surface, which was started in France in 1874. tempered safety glass is actually a kind of prestressed glass. In order to improve the strength of the glass, chemical or physical methods are usually used to form compressive stress on the surface of the glass. When the glass is subjected to external force, it first offsets the surface stress, thereby improving the bearing capacity and enhancing the resistance of the glass itself. Wind pressure, cold and heat, impact, etc.
The reason why tempered safety glass is widely used lies in its two major advantages:
The first is that the strength is several times higher than that of ordinary glass, and it is resistant to bending;
The second is the safety of use, and its increased load-bearing capacity improves the fragile nature. When the glass is damaged by external force, the fragments will be broken into small particles with obtuse angles similar to honeycombs, which are not easy to cause serious harm to the human body. In addition, the resistance to rapid cooling and rapid heating of tempered safety glass is 3 to 5 times higher than that of ordinary glass. Generally, it can withstand temperature differences of more than 250 degrees, which has a significant effect on preventing thermal cracking. It is a kind of safety glass.
Of course, there are two sides to the facts. While tempered safety glass has great advantages, it also has worrying hidden dangers:
First, the tempered safety glass can no longer be cut and processed, and the glass can only be processed to the required shape before tempering, and then tempered.
Second, although the strength of tempered safety glass is stronger than that of ordinary glass, tempered safety glass has the possibility of self-explosion (self-breaking), while ordinary glass does not have the possibility of self-explosion.
The third is that the surface of the tempered safety glass will be uneven (wind spot), and the thickness will be slightly thinner. The reason for the thinning is that after the glass is softened by hot melt, it is rapidly cooled by strong wind, so that the crystal gap inside the glass becomes smaller and the pressure becomes larger, so the glass is thinner after tempering than before tempering.
Fourth, the flat glass used in buildings after passing through the tempering furnace (physical tempering) will generally be deformed, and the degree of deformation is determined by the equipment and technicians. To a certain extent, the decorative effect is affected (except for special needs).
Why does tempered safety glass explode?
JG/T 455-2014 "tempered safety glass for Building Doors, Windows and Curtain Walls" briefly and comprehensively summarizes the reasons for the self-explosion of tempered safety glass.
"There are many reasons for the self-explosion of tempered safety glass. The phase transformation expansion of nickel sulfide particles in the glass, the stress concentration caused by bubbles and stones, excessive tempering, uneven stress of tempered glass panels, poor processing quality of glass edges and excessive size of tempered glass panels may all cause tempering. The glass exploded."
It can be seen that the expansion of nickel sulfide (NiS) is the root cause of the self-explosion of tempered glass panels. NiS is generally crystalline, and has a thermodynamic tendency to transform from α phase to β phase at room temperature, and is accompanied by a volume expansion of 2% to 3%. When the temperature change has the corresponding dynamic conditions, it can cause the self-explosion of the tempered glass panels.
Therefore, the temperature change is the direct cause of the self-explosion of tempered glass panels, which is also the reason why the self-explosion mostly occurs when the seasons change, and most of them occur in the south and west directions with strong solar radiation.
In addition to excessive internal impurities, design and construction are also related to the self-explosion of glass. Wind load, glass assembly, etc. will also change the stress distribution inside the tempered glass panels and become a possible cause of the self-explosion of the tempered glass panels.
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tempered glass panels without any treatment has not broken many times
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tempered glass panels with screws shattered with two hammers