FEM Analysis of Temperature, Stress and Strain in the Hot Extrusion of HSS Powders

摘要

FEM stress, strain and extrusion load analysis prior to the direct hot extrusion of water atomized HSS powders has been carried out. Finite element thermal modelling was used to assist in the design of the die and the definition of both the tool preheating temperature and the maximum time available for the process. Finite element thermomechanical modelling was used for the simulation of extrusion loads and stresses and strains within the powder compact upon loading. Axisymmetric compression tests at different temperatures and strain rates were carried out to provide some input data for the thermomechanical modelling. Other variables have been adjusted from the comparison between the experimental data and their corresponding simulation. From these results, it has been demonstrated that the co-extrusion of HSS together with other steels of lower yield stress allows a dramatic reduction of both the extrusion force and the maximum principal stress in the die. Additionally, the time interval in which the temperature of the billet is compatible with the process is increased.