底吹气体参数对透气砖侵蚀速度的影响

为了研究底吹气体喷吹参数(压力、流量、喷孔直径等)对透气砖侵蚀速度的影响,对比了食盐、硼砂、碳酸钠和不同比例的食盐与碳酸钠的混合物在水中的溶解速度,选定天然盐砖来模拟透气砖材质进行侵蚀水模拟试验。以水模拟钢水,在1∶10的有机玻璃模型中喷吹压缩空气,改变喷吹参数(压力、流量和喷吹时间),测量喷吹前后透气砖喷孔尺寸的变化,计算喷孔的侵蚀情况(径向侵蚀速度、轴向侵蚀速度和侵蚀角),构建气体的喷吹参数与透气砖侵蚀速度之间的关系。根据喷孔尺寸、气体的喷吹参数和无量纲数(修正的弗劳德数、雷诺数和表观马赫数等),对喷吹气体进入熔池中的流动状况进行分析,如气流中气泡的当量体积和当量直径、喷吹过程中所形成的气柱高度、气泡流和喷射流的转变等。研究结果表明,透气砖喷孔的轴向侵蚀和径向侵蚀速度均随底吹供气流量提高而增大,侵蚀角受喷孔直径、气体流量的影响很小,采用直径较小的喷孔,可以提高底吹气体对熔池的搅拌效果。研究结果对复吹技术的提高具有参考意义。

Effect of Boron Microalloying on Mechanical Properties of Low Carbon Al killed Steel Strip Produced in CSP Route

In order to investigate the influence of bottom blowing gas injection parameters (such as pressure, flow rate, nozzle hole diameter, etc.) on the erosion rate of tuyere bricks, the dissolution rate of table salt, borax, sodium carbonate, and the mixture of table salt and sodium carbonate in different proportions in water were compared, and then natural salt bricks were selected to simulate the material of tuyere bricks for erosion water simulation tests. The water was used to simulate the liquid steel, compressed air was injected in the 1∶10 plexiglass model, the injection parameters (pressure, flow, injection time)were changed, and the changes in the size of nozzle holes for tuyerebricks were measure before and after the injection, and then the erosion of tuyere bricks (radial erosion rate, axial erosion rate and erosion angle) was calculated.At last, the relationship between gas injection parameters and erosion rate of tuyere bricks were build. According to size of nozzle hole, parameters of injected gas and the dimensionless number of injection conditions (modified Froude number, Reynolds number and apparent Mach number, etc.), the flow condition of gas injected into molten pool was analyzed, such as equivalent volume and equivalent diameter of bubble in the gas flow, height of air column formed during the blowing process, transition of bubble flow and jet flow, etc. The research results show that the axial erosion and radial erosion velocities of tuyere bricks increase with the increase of bottom blowing air flow rate, and the erosion angle is little affected by the nozzle hole diameter and gas flow rate, which can improve the stirring effect of bottom blowing gas on the molten pool. These results have reference significance for the improvement of combined blowing technology.