热力学分析MnS夹杂物析出与控制

 为了深入研究与控制重轨钢中大尺寸MnS夹杂物,针对目前热力学计算MnS析出行为问题,提出在应用时需要根据实际条件做相应的选择进行计算。在比较了目前几个常用的热力学数据后,基于U75V钢中MnS夹杂物形成过程,建立了适合计算MnS夹杂物析出的分段计算方法。研究表明,采用FactSage 6.4商业软件计算MnS析出温度为1 631 K,与平衡热力学参数计算的结果1 694 K相差63 K。该方法可准确预测MnS的析出行为,降低了热力学分析MnS析出的难度。在1 473、1 573 和1 673 K 3个温度下固溶硫质量分数分别为0.000 67%、0.001 67%和0.010 8%。在铸坯轧制之前的开坯和保温温度为1 563 K时,需要将钢中硫质量分数降低到0.001 67%以下,才能有效控制大尺寸的MnS夹杂物。

Precipitation and control of MnS inclusions by thermodynamic analysis

To study and control the large size MnS inclusion in heavy rail steel. Aiming at the problems that the thermodynamic calculation of MnS is complex and difficult to be solved. It needs to be selected according to the actual conditions in a practical calculation, the main current thermodynamic parameters were compared and discussed, and then the piecewise calculation was established on the basis of the generated process of MnS inclusions in U75V steel. It is shown that the effective temperature of MnS precipitation is 1 631 K using the commercial software FactSage 6.4, this is 63 K gap by the thermodynamics parameter calculation results of 1 694 K. It can accurately forecast the precipitation behavior of MnS inclusions and decrease the difficulty of the thermodynamic analysis of MnS inclusions by the CSC method. The amounts of solid solution sulfur in steel were 0.000 67%, 0.001 67% and 0.010 8% at 1 473, 1 573 and 1 673 K, respectively. The conclusion is that the effective control MnS inclusions are more reasonable and effective by decreasing the mass percent of S less than 0.001 67% before the casting rolling and under the heating temperature of 1 563 K.