Assessment Of Residual Stresses And Microstructure Of Additively Manufactured Components In Structural Steel

Paper in proceeding, 2024

Additive manufacturing (AM) has developed and expanded into new segments the recent years. Nonetheless, the automotive industry has so far not implemented AM to any larger extent, one reason being that the availability of materials for AM has been limited. However, recently several low-alloyed carbon-containing steels suited for the automotive segments have been developed for AM. This paper addressed the heat treatment of AISI 4140 (42CrMo4) and its effect on microstructure and residual stresses. Tests have been carried out on an engine component manufactured by Powder Bed Fusion-Laser Beam process (PBF-LB) and varying subsequent heat treatments. It was found that in a regular quench and temper cycle the parts achieved a similar residual stress state as conventionally manufactured AISI 4140. Samples exposed to a direct temper cycle (tempering only after PBF-LB), showed promising results in terms of residual stresses and metallographic aspects. From the results it is concluded that the current investigation can serve as a basis to further optimization of heat treatment cycles to better utilize PBF-LB/AISI 4140 steels in the automotive sector.