Experimental Study On New Controlling Slag Carry-over Process During Continuous Casting Ladle Teeming Process With Gas Injected Into Ladle Around The Tapping Hole

During continuous casting process, it will affect the cleaniness of steel and the surface quality of casting blank if the slag flows into the tundish. Studies have shown that it can effectively improve the cleanliness of steel if we can reduce the slag carry-over. For steelmaking and continuous casting, the vortex is the most important reason which caused slag flowing into the tundish. Inspired by ladle bottom blowing refining process, if we can develop a new technology to control slag carry-over by argon blowing around nozzle, we can solve the problem of leaving too much steel in the ladle during ladle pouring economically. For this, this issue proposed physical modeling on the new technology to control slag carry-over by argon blowing around nozzle and provided the theoretical basis for developing the new technology.In this study, with a ladle selected as a prototype, a physical model scaled for 1/5 was built according to the similarity principle. The process of vortex, critical height of vortex and influencing factors of vortex were studied. Influences of gas flow, initial liquid height, atmospheric pressure, radius and width of blowing components, nozzle position and slag viscosity were investigated. The main results are as follows:(1) The critical height of vortex descends with increasing of eccentricity radio of nozzle position. It rises with increasing of initial liquid level if it is less then a certain height, but then it has little effect on critical height. We selected 230mm as the initial liquid level in this study. The critical height of vortex also descends with increasing of slag viscosity.(2) The results of physical modelling of argon blowing around nozzle have shown that: the effect of suppressing vortex becomes stronger with increasing of gas flow. We can achieve the best effect with gas flow rate rising at 0.4NL/min. It will reduce the effect with gas flow rate rising as liquid fluctuate too severely. Initial gas blowing height has little effect on critical height of vortex. The effect of atmospheric pressure also can be ignored.(3) The effect of suppressing vortex becomes stronger with increasing width of blowing components as 30mm is better than 25mm, and it also becomes stronger with increasing inner diameter of blowing components as 38mm is better than 33mm. The blowing component of inner radius of 38mm, width of 30mm is the best among the four blowing components.(4) The critical height of vortex descends with increasing of eccentricity radio of nozzle position. The effect of suppressing vortex becomes stronger with increasing of eccentricity radio of nozzle position.(5) The effect of suppressing vortex becomes stronger with increasing of slag viscosity.