Production and Characterization of a Modified Hot Work Tool Steel by Laser Powder Bed Fusion

Conventional hot work tool steels with medium carbon content, fabricated by laser powder bed fusion (L-PBF), are susceptible to cracking. To reduce this risk, as in well-established welding process, usually preheating or in-situ heating needs to be applied. In order to address this issue, a modified grade, with lower carbon wt pct, is proposed to fabricate parts showing less susceptibility to cracking. The microstructure was studied in the as-built condition and after direct double tempering for 2 hours each at 625 °C and 650 °C. Tensile properties and hardness were compared with those of wrought and (L-PBF) processed AISI H13. The results confirm improved printing performance of the new steel grade and the possibility of achieving similar hardness and strength by proper tempering treatment.