Effect of heat treatment on mechanical properties, microstructure and corrosion resistance of M789 steel produced by LPBF method

Málková Andrea - University of West Bohemia in Pilsen (Czech Republic)

The effect of heat treatment (HT) regimes on the properties of 3D printed M789 steel was studied. This steel has been developed to combine the strength of maraging steels with the corrosion resistance of stainless steels. The M789 steel was printed by LPBF and subjected to three types of HT, then the effect of temperature and change in the dwell time was investigated. The results showed that solution annealing leads to homogenization of the structure and aging leads to a significant increase in strength due to fine precipitates. The best mechanical properties were achieved for the aging regime (T = 520 °C), where Rm = 1979 ± 7 MPa, HV10 = 572 ± 3. This would make it possible to eliminate solution annealing from the production process and reduce economic costs. In future research, we will investigate the effect of HT regime on the corrosion properties of M789 steel. Subsequently, the selected modes were subjected to corrosion and three-point bending tests, and the effect of the type of heat treatment on the corrosion resistance of the steel was monitored.