The general requirements for refractory materials for electric arc furnaces include:
(1) The refractoriness should be high. The arc temperature exceeds 4000°C, and the steelmaking temperature is 1500~1750°C, sometimes as high as 2000°C, so refractory materials are required to have high refractoriness.
(2) The softening temperature under load should be high. The electric furnace works under high temperature load conditions, and the furnace body has to withstand the erosion of molten steel, so the refractory material is required to have a high load softening temperature.
(3) The compressive strength should be high. The electric furnace lining is affected by the impact of the charge during charging, the static pressure of molten steel during smelting, the erosion of steel flow during tapping, and mechanical vibration during operation. Therefore, the refractory material is required to have high compressive strength.
(4) The thermal conductivity should be small. In order to reduce the heat loss of the electric furnace and reduce the power consumption, the refractory material is required to have poor thermal conductivity, that is, the thermal conductivity coefficient should be small.
(5) Thermal stability should be good. Within a few minutes from tapping to charging in electric furnace steelmaking, the temperature drops sharply from around 1600°C to below 900°C, so refractory materials are required to have good thermal stability.
(6) Strong corrosion resistance. During the steelmaking process, slag, furnace gas and molten steel all have strong chemical erosion effects on refractory materials, so refractory fire materials are required to have good corrosion resistance.
