【作者】 张敏；

【导师】 张立峰； 陈登福；

【作者基本信息】 重庆大学 ， 冶金工程， 2011， 硕士

【摘要】 中间包是连铸过程中去除钢液夹杂的最重要的装置,为了提高铸坯质量,国内外冶金工作者开展了一系列研究工作以使中间包的冶金功能发挥得更好。其主要措施是设计合适的控流装置以延长钢水在中间包内的停留时间和减少死区体积,促进钢水夹杂物的上浮,从而提高钢水质量。本文以某厂单流中间包为研究对象,首先采用数值模拟进行前期分析,然后进行物理模拟,利用RTD曲线、冲刷速度、开始卷渣液位和流场显示等评价指标,研究不同中间包内腔结构以及不同控流装置的组合下中间包内钢液的流动状况,最终优化出合适的内腔结构和最佳控流方式组合及参数。研究结果表明:中间包底部形状为凹底结构时更加有利于减少残钢量,并且凹底尺寸越大,开始卷渣液位越低,有利于降低残钢量和提高钢水收得率;另一方面,少量增加中间包侧壁与长水口距离对于减少包壁冲刷和改善中间包流场没有明显效果。在不同流量下,各控流装置均能够在一定程度改善钢液的流动状况,但各控流装置对中间包内钢液的流动影响效果均不同,只有合理的组合才能获得最佳的效果。挡墙明显地减少了钢包注流对浇注区的扰动作用,对夹杂物的上浮具有重要作用;坝的应用能有效地改变钢水的流动路径,消除短路流,促进表面流的发展,对夹杂物的上浮去除亦有重要的作用;气幕挡墙的作用与坝类似,但由于底部气泡的上浮作用,对钢液流动影响更为明显,且气泡的存在能够更好地促进夹杂物的上浮;湍流控制器的应用很好地减缓了钢包注流对中间包壁面的冲击,且冲击区的钢液混合得更加均匀,这对促进夹杂物的上浮和减少冲击区的死区体积具有重要的意义。在没有湍流控制器的条件下,坝对中间包内钢液流动的影响比气幕挡墙效果更好;但湍流控制器在中间包内的应用,会在一定程度上减弱坝对中间包内钢液的流动的影响效果,能很好地增加气幕挡墙在中间包内的应用效果,增加夹杂物上浮的能力,因此最佳的控流装置组合为湍流控制器和挡墙与气幕挡墙的组合。工业实验证明,该中间包内30μm以上的大颗粒夹杂物基本去除,5~30μm的小颗粒夹杂物弥散分布在中间包内,中间包的冶金效果达到要求。更多还原

【Abstract】 Tundish is the most important device to remove inclusions in continuous casting process. In order to improve slab quality, a series of studies have been carried out to make the tundish metallurgy functioning better. The main measure is to set suitable flow control devices in tundish to extend the mean residence time, reduce dead volume, and promote inclusion removing, as a result to improve steel quality.Mathematical modeling and water modeling were used to study the structure optimization of one strand tundish. The structure and the flow control device were discussing by measuring the RTD curves, erosion velocity and the height of slag entrapment. Chose the best inner structure and flow control device.The results showed that concave base tundish was more favorable than the flat bottom tundish in delaying the begginning time of rotation, reducing the residual liquid steel, and improving the the yield of molten steel, and the results showed that the size of the concave base was the larger the better; Increasing the distance between the near wall and the long nozzle can not improve the flow pattern and reduce the erosion.The flow control devices could improve the liquid steel flow pattern, but the affects were different, only reasonable combinations could obtain the best results. The weir reduced the disturbance in injection zone, improved inclusions floating ratio; Dam can effectively change the application of molten steel flow path, eliminate the short circuit, promote the development of surface flow, and remove the inclusions the float; Gas curtain played the similar role to dam, but bubble floating promoting the inclusion floating; Turbulence inhibitor well slowed down the ladle wall injection flow, the liquid steel in the impact area mixture more uniform, which promoting inclusion and reducing the impact of floating dead zone. Without turbulence inhibitor in tundish, dam is better than the gas curtain; but the application of turbulence inhibitor will reduce the dam impact and increase the gas curtain effect, increasing the ability to float inclusions, so the best flow control device was weir and turbulence inhibitor and gas curtain combination.Industrial experiments shown that the inclusions larger than 30μm were removed, and 5~30μm small particles inclusions dispersed in tundish, tundish metallurgical results meet the requirements.更多还原