中锰钢静态保温和热压缩过程中铁素体转变规律

Ferrite Transformation of Manganese Steel During Heat Preservation and Thermal Compression

利用热膨胀相变仪、Gleeble热模拟机等设备、采用扫描电镜研究了C-Si-Mn-Fe系中锰钢在静态保温和热压缩过程中的铁素体转变行为,分析了不同变形条件对于铁素体转变的影响规律。结果表明:Mn元素较低的扩散系数和随时间逐渐增加的扩散阻力大大制约了静态保温条件下铁素体的转变速度;而等温变形可以促进铁素体的转变过程,且等轴铁素体成链状分布在原奥氏体晶界周围,其形貌有单层、双层和多层;变形温度越低、应变速率越小、形变量越大,铁素体转变量越大;铁素体在等温变形过程中,其含量逐渐增加,将会显著软化材料组织,降低流变应力。

The ferrite transformation behavior of C-Si-Mn-Fe medium manganese steel during static insulation and thermal compression was studied by means of SEM.The effects of different deformation conditions on the ferrite transformation are analyzed.The results show that the low diffusion coefficient of Mn and the increasing diffusion resistance with time greatly restrict the transformation rate of ferrite under static insulation.Isothermal deformation can promote the transformation process of ferrite,and equiaxed ferrite is distributed around the original austenite grain boundary in a chain.Its structure can be single layer,double layers and multi-layers.The lower the deformation temperature,the smaller the strain rate is,the larger the deformation variable,and the larger the ferrite transformation variable.During isothermal deformation,the content of ferrite increases gradually,which will significantly soften the structure of the material and reduce the flow stress.