12th Tooling Conference & Exhibition - Tooling 2022

Near full-dense and crack-free AISI H13 hot work tool steel was fabricated using laser-directed energy deposition (L-DED). Two different heat treatment schedules, i.e., direct tempering of the as-built part (DT) and austenitization and quenching prior to tempering (QT), were selected. The effect of heat treatment on the microstructure, hardness, fracture toughness (Kapp), and softening behavior of the L-DED H13 was investigated. For this purpose, the optimum austenitization schedule was identified, and tempering curves were produced. At a similar hardness level (i.e., 500 HV10), QT parts showed higher Kapp (i.e., 89 MPa√m) than that of DT (i.e., 70 MPa√m). This behavior was discussed considering the microstructural homogenization and recrystallization taking place during austenitization. The fracture toughness values obtained for both heat treatment conditions were comparable to that of wrought H13. Finally, the tempering resistance (softening behavior) of the material at elevated temperatures is discussed in the light of the initial microstructures and phases of the as-built, and quenched specimens.