Influence of powder size distribution and powder density distribution on the final shape of PM HIP-ed components

• Applicant: Professor Dr.-Ing. Christoph Broeckmann
• Subject Area: Metallurgical, Thermal and Thermomechanical Treatment of Materials
• Term: from 2011 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 202959245

The objective of the project is to develop a simulation tool for a more precise prediction of the final shape of components produced by HIP in order to replace the conventional Trial and Error method. The constitutive equation of porous powder, which depends on both plastic and viscoplastic deformation, is improved and implemented in a finite element code in ABAQUS. An important focus of this project is to gain an improved understanding of the influence of powder size distribution and inhomogeneous density distribution on the final shape of HIP-ed components. The simulation model accounts for the above mentioned factors. The methodology is demonstrated using HIP densification of a gas atomized stainless steel powder. All parameters needed for the simulation model are experimentally determined. In addition, the effect of inhomogeneous temperature distribution in the HIP vessel on the accuracy of the predicted shape is investigated in detail. Furthermore, current studies show that capsule design and capsule thickness significantly contribute to the distortion of components during HIP. Through targeted use of the effect of capsule geometry on the final component shape, the shape and size of the capsule before HIP will be optimized by employing the new methodology together with geometrical optimization. An accurate prediction model can be used together with an optimization tool in order to optimize the shape and size of the capsule before HIP. It is expected that use of the new methodology allows for the production of net-shape components with tight dimensional tolerances after HIP. The main objectives of the renewal proposal are 1. Continuation of the remaining work packages as described in the original plan. In particular remaining experimental determination of material parameters, simulations and experiments for model verification need to be performed. 2. Analysis of the influence of the powder size distribution, an inhomogeneous initial powder distribution and a temperature gradient in the HIP vessel on the final shape of components produced by HIP. 3. Manufacturing of net-shaped components using numerically optimized capsule design.

• DFG Programme: Research Grants