Research of Metal Flow Behavior during Extrusion with Active Friction

Abstract

Using numerical simulation and experiment, the metal flow behavior mechanical mechanisms in the extrusion process with active friction were investigated. The characteristic variables, second invariant of the stress deviator J 2 and the LodeÕs coefficient l were employed to partition the deformation region. It is shown that no metal flow interface occurred at the container bottom in the extrusion with active friction and the dead zone disappeared completely. The strain types of the material in the plastic deformation area decreased from three types into a single type of tension, and the homogeneity of metal deformation as well as metal flow was greatly improved. It was also indicted that the active friction was beneficial to the extrusion process and the promotion of product quality. After contrasting the result of experiment and the simulation, the displacement and the load were well correlated on both values and trends.

Derivation of the Coefficients in the Coulomb Constant Shear Friction Law from Experimental Data on the Extrusion of a Material into V-Shaped Channels with Different Convergence Angles: New Method and Algorithm

“…After inserting the expressions for the distribution law of the tangential stress (4) and σ θθ (6) into the equilibrium Equation (11), Equation ( 13) is obtained:…”

“…Mathematical modeling of thermomechanical and chemical interactions at the workpiece-tool interface and other relevant phenomena directly affecting such key process parameters as productivity, quality, and scrap level relies heavily on the finite element method (FEM) [1][2][3][4] widely used for the analysis (FEA) and optimization of various processes and technologies. FEM, a vital component of commercial and research software, is generally capable of delivering great results, but we need a precise description of the behavior of visco-plastic materials at elevated temperatures and accurate assignment of boundary conditions, especially those related to friction [5][6][7][8][9][10][11].…”

Numerical Simulation of Superalloy IN718 during Tube Hot Extrusion

“…There are amount of evident to show that the finite element method is appropriate for predicting the temperature rise for workpiece and the extrusion force which extruder act on the mandrel. In recent years, it has been become increasingly the practice in tube extrusion process to applying FEM, which mainly are focused on aluminium alloy, copper alloy and magnesium alloy [5][6][7].…”