Influence of Smelting Process and Operation AOD smelting process and operation have a great influence on the service life of the lining. The specific performance is as follows: (1) The furnace temperature is high. Studies have shown that when the bath temperature is above 1700e, the erosion rate of the lining refractories is increased by 1 time for each 50e increase in temperature. When AOD smelts stainless steel, the temperature of the molten pool in the decarbonization period is as high as about 1750e, and the lining refractories work at high temperatures for a long time. Therefore, AOD decarburization period bath temperature and refining time have a greater impact on the lining life. (2) The furnace temperature changes greatly. First of all, AOD production is a batch type, during the molten steel, the lining temperature will drop to about 1300e, and the lining temperature of the decarbonization period of the molten pool is up to 1700e or more, the reduction period is reduced to about 1650e again; second, the gas supply element All are air-cooled, during the molten steel, the lining refractories around the air gun will suddenly drop below 850e; third, the lining temperature during the smelting process is not uniform, the lining temperature in the wind eye area is high, and the lining temperature in other areas Fourth, because during the refining of stainless steel, a large amount of slagging materials, alloys, and metals need to be added to the molten pool, which will cause a sharp drop in the lining temperature at the slag line in a relatively short period of time. All of these changes the furnace temperature of AOD, resulting in lining refractories and affecting the lining life. (3) The scouring of the lining by gas and steel flow is severe. During the entire operation of the AOD, a large amount of gas (12.5m3min-1t-1) was blown into the bath. With the continuous development of technology, the oxygen strength and stirring intensity of the molten pool continue to increase. This results in strong scouring of the molten pool refractories. In particular, the rear wall of the AOD is subjected to a great deal of airflow and steel flow erosion, which will reduce the AOD furnace age. (4) The slag basicity fluctuates greatly. The AOD lining is not only affected by slag erosion and scouring, but also the slag basicity fluctuates widely in a refining cycle and its value fluctuates within 1.03.0. Especially during the reduction period, the SiO2 content in the slag suddenly rises. Under the agitation of argon, the SiO2 in the slag reacts with MgO and CaO in the lining of the basic refractory lining to form a low-melting attapulgite (CaOMgOSiO2). ) and magnesium rhodopsite (3CaOMgO2SiO2), while destroying the binding between periclase. However, these low-melting products tend to soften and fall off during AOD refining, thereby reducing the lining life.
From the above analysis, due to the characteristics of AOD refined stainless steel, lining refractories are exposed to high temperatures and temperature changes, slag erosion is serious, and they are operated under strong scouring conditions of slag and steel. The working conditions are very poor, so the furnace life is improved. very difficult.
Magnesium-silver bricks are preferred as lining refractories. TISCO's AOD linings use magnesium-chromium bricks earlier. Magnesia-chromium bricks have high high-temperature strength, but their thermal shock resistance and resistance to alkalinity greater than 1.5 are less than those of magnesium-silver bricks. Magnesium calcium bricks have good high temperature performance and can withstand high temperatures above 1750e, and can adapt to the wide range fluctuations of alkaline slag basicity. Magnesia-calcium bricks contain more CaO than magnesium-chromite bricks, and CaO can form a dense C2S layer with SiO2 in the slag, which protects the tiles from being eroded; in addition, CaO has greater creep at high temperatures. , It can delay the production of thermal stress cracks of temperature difference; In addition, the price of magnesium-silver brick is lower than that of magnesium-chromium brick, and the pollution to the environment is also small. Therefore, at present, TISCO has adopted magnesium-silica bricks (see the physical and chemical indicators) as AOD lining refractories. However, the high temperature strength and waterproof performance of magnesium-calcium bricks are not as good as those of magnesium-chromium bricks. In addition, for the fast lining erosion rate in the tuyere area, the lining thickness in the tuyere area was increased.
water purifier tap,kitchen tap with water filter,drinking water filter taps,kitchen sink filtered water faucet
Kaiping City Kaipu Sanitary Ware Co.,Ltd. , https://www.china-kpo.com