Heat treatment of 3D printed Dievear tool steel

Kučerová Ludmila - West University of Bohemia (Czech Republic)

Dievar is a martensitic hot working tool steel whose chemical composition is based on the chemical composition of AISI H13 steel (DIN 1.2344). Compared to H13, Dievar should show higher toughness and better thermal fatigue resistance. Generally, these steels are more difficult to produce by 3D printing than margaing and stainless steels with very low carbon contents. Therefore, these medium carbon tool steels have only started to be printed in recent years, and there is not much information available about them yet. The contribution will describe Dievar tool steel prepared using the laser powder bed fusion (LPBF) method and the effect of subsequent heat treatment on its microstructure and mechanical properties. After printing, this steel reaches an ultimate tensile strength of 1870 MPa at 18% ductility. It has a cellular microstructure after printing with a martensitic matrix with about 20% of residual austenite. Heat treatment of the steel was performed by tempering the steel directly from the as-built condition (without prior quenching) and also by a conventional procedure combining quenching and one or two-step tempering. By tempering without prior hardening, the highest strengths exceeding 2100 MPa were obtained.

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