In recent days, Hangzhou has opened the "barbecue" mode, which makes people cry for the high temperature. Even the glass in the community can't stand the baking, and the "self explosion" mode is turned on. Follow Xiaobian to understand the cause of high temperature glass self explosion?
Recently, an owner of Binjiang wanjiaxingcheng community broke news on the Internet, saying that the glass self explosion in the community is frequent. In the third phase alone, more than a dozen people's windows, guardrail glass and bedroom glass have self explosion in different situations, and equipped with the glass pictures of the explosion. The owner also said that he found the property, but the property responded that the window and guardrail glass had passed the warranty period. (this article is exclusively compiled by WYH, editor of sihai.com. If you need to reprint it, please indicate the source and source. Related article link: http://www.4hw.com.cn/life/anquan.html)
Why does toughened glass self explode in high temperature? Why does glass self explode
The expansion of nickel sulfide in toughened glass is the main cause of self explosion of toughened glass. After toughening, the surface layer of glass forms compressive stress. The inner core is tensile stress, and the compressive stress and tensile stress together form a balance body.
Glass itself is a kind of brittle material, which is resistant to pressure but not to tension, so most of the breakage of glass is caused by tensile stress When the crystal of nickel sulfide in toughened glass undergoes phase transformation, its volume expands. The expansion of nickel sulfide in the tensile stress layer of glass plate core causes greater tensile stress in the toughened glass. When the tensile stress exceeds the limit that the glass can bear, it will lead to the self explosion of toughened glass. (this article is exclusively compiled by WYH, editor of sihai.com. If you need to reprint it, please indicate the source and source. Related article link: http://www.4hw.com.cn/life/anquan.html)
It has been proved by foreign research that nickel is brought in by quartz sand or sandstone as the main material of glass, sulfur is brought in by fuel and auxiliary material, and nickel sulfide is formed by combustion and melting in high temperature furnace at 1400 ℃ ~ 1500 ℃. When the temperature is over 1000 ℃, nickel sulfide is randomly distributed in the molten glass as a droplet. When the temperature drops to 797 ℃, these small droplets crystallize and solidify, and the nickel sulfide is in the high temperature & alpha NIS crystal phase (hexagonal crystal). When the temperature continues to drop to 379 ℃, the crystal phase changes into beta NIS (cubic crystal system) with a volume expansion of 2.38%. The speed of this transformation process depends on the percentage content of different components (including ni7s6, NIS, nis1.01) in nickel sulfide particles and the surrounding temperature. If the transformation of nickel sulfide is not complete, the process will continue even under the natural storage and normal use temperature, but the speed is very low. (this article is exclusively compiled by WYH, editor of sihai.com. If you need to reprint it, please indicate the source and source. Related article link: http://www.4hw.com.cn/life/anquan.html)
When the glass is toughened and heated, the inner core temperature of the glass is about 620 ℃, and all nickel sulfide is in the high temperature phase & alpha NIS. Subsequently, the glass enters the air grid quench, and the nickel sulfide in the glass changes phase at 379 ℃. Different from the float annealing furnace, the quenching time of tempering is very short, and it is too late to change into low temperature & beta; - NIS, while the high temperature nickel sulfide & alpha; phase is' frozen 'in the glass. The rapid quenching makes the glass toughened and forms a uniform balance of stress under external pressure and internal tension. In the toughened glass, the transformation of nickel sulfide continues at a low speed, the volume expands continuously, and the force on the surrounding glass increases. The toughened glass core itself is the tensile stress layer, and the volume expansion of nickel sulfide in the tensile stress layer also forms the tensile stress when the phase change occurs. The two kinds of tensile stress superimposed together are enough to cause the rupture of toughened glass, namely self explosion In short, nickel is very small at high temperature, but it will become larger at normal temperature. In the heating process, the nickel element of toughened glass will be smaller, but it does not come and return to the shape of normal temperature when it is cooled rapidly, so the toughened glass will explode itself. According to the national regulations, the self explosion rate of toughened glass is 3 & permil;.