大钢锭凝固过程的温度场计算及缩孔疏松预测

PREDICTION OF TEMPERATURE DISTRIBUTION AND POROSITY AND SHRINKAGE CAVITY FORMATION DURING SOLIDIFICATION OF LARGE STEEL INGOTS

本文论述了大钢锭凝固传热过程的数学模型,并开发出一套专用的有限元模拟程序。该软件包具有完备的前、后期处理功能,可方便地用于大钢锭凝固时的温度场计算及缩孔、疏松预测。利用6t和22t钢锭的实测数据对现有程序进行了验证,证明其具有较高的可靠性和精度。以模拟程序为工具,用正交设计方法分析了锭身锥度、锭身高径比、冒口侧壁保温条件、冒口端部保温条件及冒口锥度等工艺参数对钢锭质量的影响。在此基础上,设计出132t和205t钢锭的优化锭型参数,并在实际生产中获得了成功的应用。

A mathematical model is developed to describe the heat transport process in a solidifying steel ingot, and the numerical solution of the model is carried out using a FEM computational program. Aided by its powerful preprocessing and postprocessing capabilities, the FEM program can readily be used to predict the temperature distribution and the porosity and shrinkage cavity formation during salidification of large steel ingots. The excellent agreement obtained between measurements and predictions for solidification of 6 t and 22 t ingots shows a full validation of the technique employed. By use of the orthogonal analysis method and the FEM programs the influence of several process factors on the quality of steel ingots is investigated. Based on this, new 132 t and 205 t ingots with optimized mould factors are designed and put into practical use, resulting in remarkable yield and quality improvements.