Authors:
Marie Luise Scheck (1), Rui Joao Santos Batista (3), Simone Herzog (2), Anke Kaletsch (1,2), Constantin Häfner (3,4), Christoph Broeckmann (1,2)
1- Institute for Applied Powder Metallurgy and Ceramics (IAPK) at RWTH Aachen e.V., Germany
2- Institute for Materials Applications in Mechanical Engineering, RWTH Aachen University, Germany
3- Fraunhofer Institute for Laser Technology ILT, Germany
4- Laser Technology LLT, RWTH Aachen University, Germany
Abstract:
Processing carbide-rich tool steels with laser-based powder bed fusion is challenging as cracks occur frequently. Substrate plate preheating is commonly applied to improve the processability as the temperature gradients are lowered and stresses reduced. The modified temperature gradients alter the microstructure formation of the alloy. In this study, a carbide-rich tool steel was processed at RT, 500°C and 800°C substrate plate preheating which lead to different precipitated carbide and retained austenite contents. The high substrate plate heating of 800°C significantly reduced cracking of the alloy and a fully martensitic microstructure was obtained. In the samples built at RT or 500°C, the lower diffusion hinders carbide precipitation and thus leads to austenite stabilization. These specimens show cracks despite their higher retained austenite contents. Here, the retained austenite has a high hardness, and therefore it is assumed that it is distorted, brittle and thus cannot prevent crack growth within the specimens.
DOI:
https://doi.org/10.59499/EP246281362
