二冷模式对82A帘线钢小方坯质量的影响

Effect of Secondary Cooling Mode on Billet Quality of 82A Cord Steel

帘线钢小方坯质量受二冷模型的影响较为明显,为探明二冷模式对82A帘线钢小方坯质量的影响,本文对82A帘线钢的高温力学性能进行了研究,并建立了连铸过程凝固传热模型,根据不同二冷模式下铸坯测温结果对模型进行了校正。模拟结果发现,与二冷弱冷模式相比,采取二冷强冷模式时连铸坯在二冷区表面温度迅速降低,在空冷区回温速率较高,而且矫直点处表面温度较低,容易导致铸坯裂纹的产生。工业试验结果表明,二冷强冷有助于降低连铸坯中心偏析,提高连铸坯中心组织致密度,减轻中心疏松和中心缩孔,但是会导致铸坯中心等轴晶率降低,并易导致裂纹的产生。

In order to explore the influence of secondary cooling mode on the billet quality of 82A cord steel,the high-temperature mechanical properties of 82A cord steel are studied,the solidification heat transfer model of the continuous casting process is developed,and the model is corrected according to the billet temperature measurement results under different secondary cooling modes.The simulation results show that compared with weak cooling mode,under strong cooling mode,the surface temperature of the continuous casting billet in the secondary cooling zone decreases rapidly,the temperature return rate in the air cooling zone is higher,and the surface temperature at the straightening point is lower,which is more likely to lead to billet cracks.The industrial test results show that strong secondary cooling can reduce the central segregation of billet,improve the density of the central structure,reduce the central porosity and central shrinkage,but it will reduce the central equiaxed grain rate and easily lead to cracks.Therefore,it is necessary to reasonably set the secondary cooling system of 82A cord steel billet to achieve the effect of comprehensive control of billet segregation and crack.