Densifying and hardening of martensitic steel powders in HIP units providing high cooling rates

Abstract

Hot isostatic pressing (HIP) units are worldwide used for the compaction of metal alloy powders. The cooling rate in a HIP unit is usually comparatively low. This lengthens cycle times and requires an additionally heat treatment for quenched and tempered steels. Novel cooling HIP concepts in HIP units feature high quenching rates. In this study, tool steels were investigated with respect to their time–temperature–transformation behaviour for different cooling parameters. The paper shows that encapsuled powdered tool steels can be compacted and hardened in the HIP unit. The examined steels exhibit a comparable or even a higher hardness and a finer microstructure. HIP units with high-quenching rates enable to compact and heat treat materials in one step.

Keywords:

• Compaction
• Cooling
• HIP

Acknowledgments

Financial support of the Deutsche Forschungsgemeinschaft (DFG) under contract of Transregio 103 is greatfully acknowledged.