38MnVS6非调质钢大尺寸棒材往复热轧过程微观组织演化数值模拟

Numerical simulation of microstructure evolution during hot reversible rolling process of large-sized 38MnVS6 non-quenched and tempered steel rod

以热压缩实验所得38MnVS6非调质钢微观组织演化数学模型为基础,利用非线性有限元软件MSC.Marc,建立了38MnVS6非调质钢Φ90mm棒材往复热轧过程三维热-力-组织多场耦合有限元模型。微观组织演化数学模型通过MSC.Marc子程序与轧制热-力耦合有限元模型相耦合。计算并分析了38MnVS6非调质钢棒材10道次往复热轧过程中轧件的温度、再结晶分数以及奥氏体晶粒尺寸的分布和演化。结果表明,由于截面尺寸较大,轧件的温度场具有不均匀性,进而导致微观组织场的不均匀性。轧制过程轧件表面温度及轧制后奥氏体晶粒尺寸的实验值和模拟值吻合较好,验证了模型的准确性。

Based on the microstructure evolution mathematic models of 38 MnVS6 non-quenched and tempered steel obtained by hot compression tests, a thermal-mechanical coupled 3D finite element （FE） model of hot reversible rolling process for φ90mm 38 MnVS6 non-quenched and tempered steel rod was established by non-linear FE software MSC. Marc. The microstrueture evolution mathematic models were coupled in the thermo-mechanical FE model by a MS（;. Marc subprogram. The ten-pass hot reversible rolling processes were simulated, and the distribution and evolution of different field-variables, such as temperature, recrystallization fraction and austenite grain size were obtained and investigated. The results reveal that the temperature and microstructure distributions are uneven due to the large cross sectional dimension. The simulation results of the temperature of the rolled piece surface as well as the austenite grain size after rolling are in good agreement with the measured ones. The comparisons show the validity of the model.