| 摘要 |
PURPOSE:To produce a reinforced glass plate having uniform distribution of surface stress by eliminating the warp of a cooling plate in a reinforcing device of glass plate by the contact of solid by regulating the heat conductivity and the coefft. of thermal expansion to specified values. CONSTITUTION:In a reinforcing device which quenches hot glass plate between cooling plates, the cooling plates are made of a material having a heat conductivity higher than the least minimum value necessary for the quenching of the glass plate and <=1X10<-6>/ deg.C coefft. of heat expansion. Said least minimum heat conductivity for the quenching of the glass plate is ca. 40kcal/m.hr. deg.C. In a more preferable embodimenet, the material for the cooling plate is boron nitride. By this constitution, the contact pressure of the cooling plate on the glass plate becomes uniform and the surface stress of the glass plate is made uniform and high level.
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