The float glass furnace production line has been operating for seven years; the hook bricks of the furnace generated stress due to temperature change, and broke and fell off due to erosion by glass metal and various complex gases in furnace. A defect about 5,000mm long was caused, and the flame penetrated to the outer space of the furnace, and led to high local temperature in the furnace, reducing the strength of the support plate and inward inclining of the parapet wall, which posed a serious threat to the structure safety of the furnace. With the company's high temperature ceramic welding technique combined with the high temperature furnace periscope, the fracture on hook bricks was welded, thus effectively protecting the support plate and prolonging the service life of the furnace for another 15 months.