Development of powder bed fusion – laser beam process for AISI 4140, 4340 and 8620 low-alloy steel

This study focuses on process development and mechanical property evaluation of AISI 4140, 4340 8620 low-alloy steel produced by powder bed fusion – laser beam (PBF-LB). Process found that increasing the build plate preheating temperature to 180°C improved processability, as it mitigated lack cold cracking defects. Subsequent testing steels achieved a high ultimate tensile strength (4140:?1400 MPa, 4340:?1500 8620:?1100 MPa), impact toughness (4140:?90–100 J, 4340:?60–70 8620:?150–175 J) elongation (4140:?14%, 4340:?14%, 8620:?14–15%) met or exceeded ASTM standards. Mechanical also revealed limited directional anisotropy was attributed low levels internal defects (< 0.1%), small grains with weak crystallographic texture tempering due post PBF-LB stress relief. indicates adequate development, can meet exceed performance conventionally alloys.