板坯连铸机二次冷却均匀性的分析与优化

Analysis and optimization of secondary cooling uniformity of slab continuous caster

针对某厂连铸板坯裂纹频繁出现的问题,结合连铸机的喷嘴布置特点,在测试分析铸机喷嘴的喷淋冷却特性的基础上,以Q235G钢为对象,考虑板坯宽度方向二冷水流密度分布状态,采用数值仿真方法模拟计算了200 mm×1350 mm连铸坯的凝固壳生长形貌及铸坯表面内弧温度分布。研究表明:板坯铸机二冷前期足辊段与零段原喷嘴布置及水流密度分布不合理,提出了调整喷嘴靶距改善板坯宽度方向冷却强度分布均匀性的解决方案,实现了凝固坯壳的均匀生长和温度的均匀分布,有效减少了铸坯裂纹。

In view of the frequent problems of cast slab crack in a factory,combined with the arrangement characteristics of the caster nozzle,on the basis of testing and analyzing the spray cooling characteristics of the caster nozzle,taking Q235 G steel as an example and considering the distribution of secondary cooling water flow rate along the width direction of slab,the growth morphology of solidified shell and the temperature distribution on the inner surface of 200 mm×1 350 mm continuous casting slab were simulated and calculated by numerical simulation. The results showed that,the nozzle arrangement and the water flow rate distribution of foot roller and segment zero were unreasonable in the early stage of secondary cooling of slab caster. And then an optimization scheme by adjusting the nozzle location was proposed to improve the uniformity of cooling intensity distribution in slab width direction,and to improve the uniformly growth of solidified shell and the even distribution of slab surface temperature,which effectively reduced slab cracks.