Abstract: High temperature bell-type annealing furnace is an extremely important part of the production process of grain-oriented silicon steel. In the early stage of production, the bottom heating resistance belt was fused, which led to the failure of the bottom heating system to operate normally. When the high temperature bell-type furnace was not normally put into the bottom heating system to produce grainoriented silicon steel, it was found that there were some quality defects such as spot-like crystal leakage and large iron loss at the head and tail, which affected the magnetic properties of steel coils. In this paper, through physical and chemical analysis of the fuse site and melt of the resistance belt, and through metallographic detection, electron microscope scanning, chemical composition detection, the content of P in the refractory brick was found exceeding the standard, which led to the electric corrosion reaction with the resistance belt at high temperature stage, resulting in the resistance belt disconnection. 

Key words: bell-type annealing furnace, resistance belt,  , bottom heating, fusing