| 摘要 |
PURPOSE:To obtain window glass for construction having superior breaking strength and high safety by heat treating large-sized thick plate glass such as window glass for a multistory building under specified conditions. CONSTITUTION:A thick window glass plate of 13-19mm thickness for a multistory building is heated to 550-600 deg.C and cooled by intermittently blowing air with a period of 0.5-20sec. The cooling is controlled so as to regulate the coefft. of heat transfer to 5-20kcal/m<2>.hr. deg.C during air blowing and to <=2kcal/m<2>.hr. deg.C during cessation of air blowing. The breaking strength of the plate glass is improved and a window glass plate for construction having high safety is obtd. Unlike conventional tempered glass the glass plate does not break to small pieces. |
