Influences of Smelting Technics on AOD Furnace Lining

Influences of Smelting Technics on AOD Furnace Lining

1. High Furnace Temperature

2. Long Smelting Cycle

3. Great Temperature Change

And the reasons are as follows.

Research shows that when the temperature of the molten pool is above 1700 ℃, the erosion rate of the lining will be doubled for every time of temperature increases by 50 ℃. When AOD furnace is smelting stainless steel, the molten pool temperature is above 1750 ℃ during decarburization phase, with a long smelting cycle of stainless steel, the woking time of lining refractories is relatively long, and thus speed up the refractories erosion.

Because of the intermittence of producing, the lining temperature will fall to 1300℃ after molten steel flows out. Before pouring into semi molten steel, there is still protecting gas blowed in from air pressure gun, then the temperature of lining around will fall to under 850℃. During the process of smelting, exothermic reaction will emerge between oxygen mixed gas entered from tuyere and elements in molten steel, and this will lead to relatively higher temperature of tuyere area, and other parts are at lower temperature. Plenty of cold metal will be added into the molten pool during stainless steel refining, so it will result in rapid temperature decline of slag line.

The above several situations of abrupt increase and decline of temperature will easily lead to exfoliation of lining, finally reduce the furnace service life.