Damage Investigation Of No.11 Blast Furnace Hearth In Ansteel

This paper analysis the samples of blast furnace by means of X-ray diffraction, scanning electron microscopy and other modern technology and equipment aiming at the damage of No.11 BF bottom and hearth at Anshan Iron and steel,and analysis the results in the blast furnace hearth damage causes by software simulation of hearth temperature field and stress field.The research work and main achievements of this paper include the followings:1 The carbon bricks are built 4 layers instead of 5 layers in bottom in the brickwork of the blast furnace and the cooling pipes are old without replacement,resulting in the poor effect of the initial furnace bottom. These are the part of reasons of the hearth damage.2. Analysis of the special material and the load by alkali metal and zinc: the alkali metal composite load（K₂O+Na₂O） is at 2.491 kg/t and zinc load is maintained at 0.170 kg/t in 2011 to 2013 years, respectively, are also in the low level at home.The sampling analysis of zinc load of tuyere zone is high and low titanium content in hearth.3. Analysis of the carbon brick erosion in hearth and bottom: serious erosion of hearth brick, but the erosion surface is smooth; there is no difference in the center and edge zone erosion depth, and it forms pan bottom shape of erosion. The most serious erosion position is near the east entrance, and the thickness of residual carbon brick respectively 260, 350 and 270 mm; the erosion of the second-tier and three-tier is the most serious.4. Software simulation: temperature field simulation results show that blast furnace hearth ceramic structure is complete, and high heat resistance ceramic structure gives full play to the role of thermal at the time of initial furnace; when carbon bricks erode thickness, temperature distribution becomes not uniform, bottom and hearth side wall temperature gradient is very large, hot face brick completely close to the temperature of molten iron; and cold face brick with the lowest temperature has also been close to 700 degrees and it is extremely easy to occur hearth burn through if not to take timely measures. Stress field simulation results show that the situation promote the radial thermal stress from heat towards the central focus when the carbon brick chipping size changes in the range of 30 to 70mm; when chipping size continues to increase to 90 mm, radial stress region with the large force is still at the center of the distribution.