关键词: 凹模型线, 挤压, 数值模拟, 钢轨脱碳层, 黏滑分布, 瞬态滚动接触, 塑型变形, 显式有限元法

Abstract: Numerical simulation with rigid plastic finite element method and experimental investigation with grid method and Mori6 technique were used to study the effect of die profiles on the flow during metal extrusion. Velocity, strain rate, stress and temperature field in the workpieces extruded with conical die, cosine curved die, constant strain rate curved die, hyperbolic curved die, ellipitical curved die and Richmond curved die as well as newly designed sine curved die were calculated. Boundary conditions of F. E. M. were checked with Mori6 pattern. Results show that among the seven kinds of dies, the best one is the newly designed sine curved die and the next is the cosine curved die. These dies carry out lower extrusion loads and more homogeneous strain distributions.

Key words: 凹模型线, 挤压, 数值模拟, adhesion-slip distinction, explicit finite element method, plastic deformation, rail decarburization layer, transient rolling contact