Hybrid Wire- and Powder-based Laser Metal Deposition for Modification of Local Properties of H11 Dies

Hot work tool steel X37CrMoV5.1 (AISI H11) is largely used to produce highly stressed hot forging dies due to its high levels of hardness, temper resistance and toughness. This steel is exposed to high thermo-mechanical loads, which reduce its hardness and toughness and lead to the failure by wear and surface cracks. To address such kind of failures, the present study was performed to implement the novel wire- and powder-based laser metal deposition (WP-LMD) process and realize its potential to modify the local mechanical properties of H11 dies. The process was employed to fabricate standard tensile specimens (DIN50125) out of H11 wire and Nb powder. These specimens were subjected to various heat treatment sequences, and subsequently tested for microhardness and tensile properties. The mechanical properties were compared for samples with and without addition of Nb. This study revealed the potential of WP-LMD process to refine the microstructure, to reduce carbides' size, and to modify the local mechanical properties of H11 dies.