CHANGE IN MICROSTRUCTURE AND HARDNESS OF ADDITIVELY MANUFACTURED AISI H13 STEEL BY HEAT TREATMENT AND NITRIDING PROCESSES

AISI H13 steel samples were additively manufactured using a laser powder bed fusion (LPBF) system. The effect of annealing tem-perature, quenching & tempering, and nitriding determined. microstructure properties the investigated optical microscopy, scanning electron backscattered diffraction, probe micro-analysis, X-ray roughness measurement, hardness tester. results show that as-built sample had on surface pores inside. consisted martensite retained austenite. average was 460 HV, porosity 0.086 %. process helped homogenize microstructure, increase density, reduce LPBF-manufactured sample. to maximum 787 then tempering reduced 572 HV. Heat treatment processes tended block size, austenitic content, precipitate V-Mo-rich carbide in steel. After conducted, case depth 87 um, increased up higher than 1020 HV due formation CrN Fe3-4N.