The working layer of the roof is affected by high-temperature air erosion and thermal stress and other factors, especially the front portion of the heating section, and the soaking section of the roof is easily damaged, which is the weak link of the entire roof.
Due to the composite structure by the insulation material and the working layer, the furnace temperature rise and thermal stress drop fluctuations and structural tensile stress of the anchor brick damage, will cause varying degrees of damage to the roof.
Considering above actual working conditions in the reheating furnace, the incorrect choice of refractory castable, inappropriate operation during installation and drying furnace, any of these situations will cause the roog a large area of layered collapse.
furnace roof damage 
furnace roof cracks
By observing the roof structural damage, the cracks are most likely because the castable performance can not meet the actual working conditions of the furnace. Consideration of the material: thermal shock stability, thermal expansion performance and linear rate of change, and strength at high temperature.
Usually, low cement castable is a better choice for the furnace lining. Compared with castable, refractory plastic has good resistance to peeling, better performance of thermal shock resistance, long service life, the most suitable material for furnace roof. The application of refractory plastic, with superior performance, has also been a good effect, in the domestic large-scale continuous furnace.
