To ensure a stabilized operation of long lifetime while minimizing the joint and facilitating the installation by employing a cover comprising a single or a plurality of precast blocks in a metal melting furnace.
A precast block 3 for small ceiling, a precast block 4 for large ceiling, and a castable 5 are built in an iron cover for furnace while being arranged. The precast blocks 3 for small ceiling have an empty joint, the precast blocks 3, 4 for small and large ceilings have an expansion margin of 50 nm for pouring castable of 80% alumina and a ceramic sheet of 30 mm 15 arranged in the gap between the precast block 4 for large ceiling and the iron cover. According to the structure, a smooth surface can be obtained and the lifetime (number of times of use) can be prolonged significantly.
HIBINO MITSUNOBU
CHIHARA KENJI
YAMADA IWAO
