Numerical three dimensional simulation of cold compaction and springback for prealloyed powder composites

Abstract

Unlike conventional iron based alloys, prealloyed powder composites experience significant dimensional changes during springback and sintering. As a result, the final compact size is significantly different from the die geometry. This dimensional change presents one of the challenges to the wide usage of prealloyed powder composites in traditional press and sinter applications. Finite element modelling of the compaction and sintering of these composites can help predict the dimensional changes and enable tooling design for net shape moulding without the need for multiple iterations on the die design. Constitutive models for powder compaction are used to simulate the compaction of a gear made of prealloyed powder composite. Numerical simulation is used to predict the relative density and stress distribution within the compact as well as the stress distribution within the tooling. The simulation tracks the relative density and stress distributions during compaction and ejection; the springback after ejection of the part from the die is also calculated. Measurements of the density distribution within a compact and springback show good agreement with the FEA simulation results.