FLAT GLASS TO BE TEMPERED

摘要

A flat glass to be tempered, characterized in that it forms, when it is subjected to thermal tempering treatment, a tempered glass having a thermal tempering coefficient, which is represented by a quotient obtained by dividing a surface compression stress (MPa) by a sheet thickness, of 35 to 75; and a composition of glass for the flat glass. The flat glass has preferably a thermal stress coefficient represented by a product of an average coefficient of linear expansion and a Young's modulus of 0.70 to 1.20 Mpa/<C. The flat glass can be used for producing a thin tempered flat glass which has a real thickness of 6 mm or less, preferably 3.1 mm or less, and exhibits a satisfactory surface compression stress without increasing the capacity of a tempering process to be used.