Arc furnace shell : structure and working environment

The furnace shell is usually cylindrical with a truncated conical bottom and a spherical disc bottom for good strength.  The furnace shell bears the weight of the furnace lining and metal, and also bears the thermal stress caused by the thermal expansion of the furnace lining.  In general, the temperature in most areas of the furnace shell is approximately 200°C.  The furnace shell temperature is higher when the furnace lining is partially burned.  In some small stoves, the top of the furnace, electrode lifting, tilting furnace and other mechanisms are directly connected to the furnace shell, the furnace shell and the door, steel outlet and so on.  

The furnace shell is required to have sufficient mechanical strength and stiffness.  The furnace shell shall be tightly welded with horizontal and vertical reinforcing plates, especially around the opening.  There are special welding rings along the furnace shell, and the reinforcing rings are often water-cooled to prevent deformation.  But the whole furnace body has a tendency to deform because it can not expand freely.  Some large electric furnace with cage shell, in addition to the furnace part of the shell and the bottom is welded steel plate into the whole, the upper half of the shell is cage, by vertical and horizontal steel pieces welded into the internal shell steel plate.  

Recently, water - cooled blocks can be directly hung in the cage shell as the furnace wall.  Horizontal support can be made of steel pipe, as water cooling block water supply and drainage main.  The diameter of 3~4m furnace, furnace shell and lining can be replaced as a whole, speed up the furnace repair time, in a larger furnace, furnace shell made into two parts can be separated, the joint should avoid slag line, the upper shell and furnace wall can be lifted away together.  Many holes should be drilled evenly on the steel plate of the furnace shell to eliminate the moisture in the oven.