Discover world-changing science. "Heat-treated glass" is made of normal glass heated to extreme temperature and than cooled rapidly. Both have their own advantages and disadvantages. Recommended temperatures vary but the glass reaches temperatures of over 600°C. A tempered glass breaks into several small blunt pieces. It gets its strength from an intense heat and cooling treatment, and it is, therefore, resistant to heat and breakage. Tempering is a heat treatment process of glass to increase it’s strength and change the shattering properties. This is why tempered glass is often called “safety glass.” If tempered glass is quenched, how is regular glass cooled? More specifically, glass is made by heating ordinary sand (mostly composed of silicon dioxide SiO 2) until it melts and turns into a liquid. Because of this, tempered glass offers strength and safety to both drivers and passengers if an accident or a broken window were to occur. This material is typically made of “annealed” glass. Because of this, the interior zone of the glass stays in tension while the surface goes into compression. As the center of the glass cools, it tries to pull back from the outer surfaces. Another way to tell if you have tempered glass is by using polarized sunglasses, which will allow you to see a fuzzy black diamond or circular pattern to the tempered glass. In contrast to the instant cooling of tempered glass, the … Thermal Tempering Process for Tempered Glass The thermal tempering process happens when the tempered glass is rapidly cooled or quenched at a specific temperature by using symmetrically placed air jets. An abrasivesuch as sandpapertakes sharp edges off the glass, which is subsequently washed. Glass shards are very dangerous, and tempered glass is made to crumble into small pieces, which is a lot safer. Another thing you will like about tempered glass is how they protect phone screens from being destroyed. It can be used in microwaves because of its ability to retain itself and its strength. To prepare glass for the tempering process, it must first be cut to the desired size. After the heating process, the scorching piece of glass undergoes a cooling process. For instance, standard window glass will break when the temperature reaches approximately 250° F. Tempered glass can last until about 500°F. (Strength reductions or product failure can occur if any fabrication operations, such as etching or edging, take place after heat treatment.) Tempered glass can be made using any type of glass compostition (not just window glass - soda lime silicates). During the manufacturing process, this type of glass is heated up intensely in a special tempering oven, then cooled down with a special quenching procedure that cools down the exterior surfaces of the glass much quicker than the center. Silicon Dioxide (Sand) Float Glass (Soda Lime) Made from sand, calcium carbonate (soda), and calcium oxide (lime) ... How does Tempered Glass break? To ensure the integrity of the glass, cutting must take place before the tempering process begins. The glass is washed to remove dust, dirt, and debris that could interfere with the thermal tempering process. Tempered glass is most likely to only crack in situations where the normal glass would shatter. Tempered glass, according to federal specifications, must have a surface compression of 10,000 psi or more; it generally breaks at approximately 24,000 psi. However, in reality, most glass offers little, if any, fire protection. The use of tempered glass offers the benefit of safety in … Step 3. Scientific American is part of Springer Nature, which owns or has commercial relations with thousands of scientific publications (many of them can be found at. 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