连铸凝固过程热模拟实验方法及应用案例

Thermal simulation technique for solidification process of continuous casting and its application

凝固是制约冶金产品质量的重要环节,但因高温、不透明、大规模和连续化的生产特点,连铸生产条件下的凝固问题研究极为困难。目前的研究方法主要包括数值模拟、物理模拟和热模拟,其中热模拟方法因可以直接获取接近生产条件的实验数据而备受关注。本工作系统介绍了连铸凝固热模拟研究方法,简述了热模拟技术原理,并对结晶器热模拟方法及特征单元热模拟方法的原理和应用进行总结。其中,基于特征单元热相似性提出的连铸坯枝晶生长热模拟及凝固裂纹热模拟等方法成功地将十几吨铸坯的凝固过程“浓缩”到实验室用百克钢研究,不仅可以揭示钢液成分、浇注和冷却条件等因素对凝固过程、组织和元素分布的影响规律,而且还可以获得铸坯固液界面形貌、界面前沿溶质扩散和夹杂物演变、凝固裂纹形成的可能性及条件等其他手段无法得到而冶金界非常关注的问题。

Solidification is an important process governing the quality of metallurgical products,but the study of solidification process under continuous casting condition is extremely difficult result from the high temperature,opaque,large-scale and continuous production.The current research methods mainly include numerical simulation,physical simulation and thermal simulation,among which thermal simulation method is of great interest because the experimental data similar to the production conditions can be directly obtained.This work systematically introduces the methods of thermal simulation for continuous casting solidification.The principles of thermal simulation techniques are briefly described,and the applications of the mold thermal simulation method and the characteristic unit thermal simulation method are summarized.Among them,the thermal simulation methods for dendritic growth of continuous casting billet and hot tearing based on the heat conduction similarity have successfully"condensed"the solidification process of a dozen tons of cast billet into a laboratory study with 100 grams of steel.Both the methods can not only reveal the influences of composition,pouring and cooling conditions on solidification process,microstructure and solute distribution,but also can observe the morphology of solid-liquid interface,diffusion of solute,evolution of inclusions,and the possibility of hot tearing formation,that are regarded as extremely important issues in metallurgy filed but cannot be obtained by other means.