Hardness of 9H (9H hardness 9 = corundum (sapphire) grinding hardness 1000 according to Rosiwal only the diamond is harder = 10H) Tempered glass is a type of glass in which mechanical stresses are specifically created in the material through heat treatment As a result of this quenching, the surface solidifies and the external dimensions of the component now only change comparatively little. However, the warmer core continues to contract even more, as the thermal expansion above the transformation point is significantly higher than below it. Thanks to this frozen pre-tensioning, the tempered glass can compensate for significantly higher tensile loads than untreated glass. Since the compressive strength of glass significantly exceeds the tensile strength, this represents an overall impro.
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