250t钢包底吹氩精炼工艺优化的物理模拟

Physical simulation of refining process optimization for bottom argon blowing in a 250 t ladle

以250t底吹氩钢包为原形,根据相似原理进行水模型实验,研究了不同透气砖布置参数、吹氩量、加料位置及透气砖透气性能变化对精炼效果的影响.结果表明:0.75R(透气砖在距钢包底部中心为0.75倍钢包底部半径R的位置)的双透气砖布置较0.64R、0.5R混匀时间短,但对包壁的冲刷严重;双透气砖大夹角(135°、180°)布置比小夹角(45°、90°)混匀时间短,0.64R-180°的双透气砖对称布置方案最优.在透气砖上方或双透气砖连线中垂线区域内添加物料,混匀时间最短;吹气量控制在67~70m3/h之间,可充分利用气体的搅拌能量,满足混匀时间短且不会产生卷渣的洁净钢精炼要求;透气砖堵塞较双孔正常吹气混匀时间延长,顶部钢液形成两个大小不一的裸露亮圈,并加重对包壁耐材的冲刷与侵蚀,降低钢液的混均效果及钢的洁净度.

The influence of different permeable brick layout parameters,gas flowrate,feeding location and change in permeability of permeable bricks,on the refining effect was investigated by using water model experiment according to the prototype of a 250 t ladle with bottom argon blowing. It is shown that the mixing time of liquid steel with an arrangement of two permeable bricks at 0. 75R( the position from the center of the ladle bottom to permeable bricks is 0. 75 times the radius R of the ladle bottom) is shorter than that of permeable brick arrangements at 0. 64 R and 0. 5R,but this permeable brick arrangement results in a serious erosion of the ladle wall.Moreover,the mixing time of liquid steel with an arrangement of two permeable bricks at larger angles( 135°,180°) is shorter than that at smaller angles( 45°,90°). Thus the 0. 64R-180° arrangement of two permeable bricks is the optimal solution. When material for liquid steel refining is added above permeable bricks or in the perpendicular bisector zone of the connection line of two permeable bricks,the mixing time of liquid steel is the shortest. The optimal bottom gas-blowing flowrate is 67 to 70 m3·h- 1,which can meet the clean steel production requirement,i. e.,the mixing time of liquid steel is short,slag entrapment can be avoided,and the gas mixing energy can fully be used. The mixing time of liquid steel under the condition of permeable brick clogging prolongs and two bare bright circles with different sizes form in top liquid steel,which increases the erosion of the ladle wall refractory and reduce the mixing effect and cleanliness of liquid steel.