【作者】 董其鹏； 张炯明； 赵新凯； 王博；

【Author】 Dong Qipeng;Zhang Jiongming;Zhao Xinkai;Wang Bo;State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing;

【机构】 北京科技大学钢铁冶金新技术国家重点实验室；

【摘要】 连铸坯低压缩比轧制是厚板生产的发展趋势,然而探伤不合一直是限制此技术应用发展的主要原因。因此,本研究在轻压下技术的基础上提出凝固末端重压下技术,欲充分利用铸坯凝固末端高温、大的温度梯度等有利条件,施加大的压下量,以达到有效控制铸坯内部质量的目的。本文先利用TherCast软件对铸坯凝固过程进行了模拟研究。模拟结果显示了铸坯凝固过程中表面和内部温度变化曲线,以及铸坯内部固相率和钢水静压力的变化。确定铸坯中心固相率后,为了分析压下位置,选取了三个压下位置对铸坯实施10mm的压下量。研究发现,压下位置在f_s=0.86以后时,对铸坯内部偏析无改善效果,但此时压下有利于改善内部疏松,并且产生内部裂纹可能性较小。最后,研究了两种不同的重压下模式对铸坯坯壳变形和等效应变的影响,发现相同压下量,单辊压下比扇形段压下坯壳变形量稍大,而等效应变稍小。更多还原

【Abstract】 The development tendency for the production of heavy plate is rolling with small reduction ratio, however, the technology is mainly limited by ultrasonic test defects. Therefore, in order to control internal quality of slab effectively, a novel technology named heavy reduction at the end of solidification is presented here, basing on the soft reduction process, taking full advantage of high temperature and large temperature gradient to implement large reduction amounts. Firstly, the solidification process of slab was simulated using TherCast. Results showed the evolutions of surface temperature, central temperature, central solid fraction and ferrostatic pressure. Then, to analyze the influence of reduction position, three reduction positions were chosen to implement heavy reduction with reduction amount of 10 mm. The study found that implementing heavy reduction at the position with large solid fraction(0.86 here) cannot improve the segregation, but is good for the improving of porosity. Moreover, the possibility for the internal crack is very small. Finally, two different models of heavy reduction were simulated to study the effect on the deformation of shell and equivalent strain. Results showed that if implemented the same reduction amounts, the deformations of shell for the model with single roller are bigger, but with smaller equivalent strain.更多还原