基于晶体塑性学的铁素体不锈钢表面起皱有限元分析

Crystal Plasticity Finite Element Analysis of Ridging Generation of Ferritic Stainless Steel

针对成形过程中铁素体不锈钢薄带存在的表面起皱问题,基于晶体塑性学建立了有限元仿真模型并通过一系列实验进行了相关验证分析,模拟计算了不同晶粒大小的铁素体不锈钢薄带在20%延伸率下的起皱高度。经研究发现,铁素体不锈钢表面的起皱现象主要源于晶粒的滚动与滑移变形。在成形过程中,大尺度晶粒所形成的具有特定取向(如{001}<110>)的晶粒簇易于产生较大的塑性变形,与周边晶粒产生的塑性变形形成差异,导致严重的表面起皱现象,结果表明铁素体不锈钢在成形过程中的起皱高度与材料的平均晶粒尺寸基本呈正相关。研究结果可为表面质量良好的铁素体不锈钢薄带轧制工艺制定提供理论参考。

Aiming at the surface ridging defects of ferritic stainless steel(FSS) strips generated during forming processes, a crystal plasticity finite element model was proposed and verified by a series of experiments. Based on the established model, the ridging height of FSS strips with different average grain sizes after 20% extension were calculated. The results show that the ridging phenomenon is mainly originated from rotation and slip of grains. During forming processes, severe plastic deformation of grain colonies(for example, the {001} <110> colonies) formed by large grains occurs and leads to remarkable difference with plastic deformation of neighboring grains, inducing significant surface ridging on the surface of FSS. The results indicate that the ridging height of FSS during forming processes is almost proportional to the average grain size. The research results can provide theoretical basis for the rolling processes of FSS thin strip with high surface quality.