Surface Integrity of 20MnCr5 Laser Powder Bed Fusion parts subject to contact fatigue test

Abstract

Additive Manufacturing (AM) is vital for industrial innovation, offering high potential for groundbreaking solutions. However, its successful implementation still depends on overcoming several challenges. Particularly, the assessment of surface integrity in AM-generated components, and its degradation when subjected to contact stresses presents an ongoing endeavor. Within this context, the current work delves into the study of the surface integrity of 20MnCr5 case-hardened samples manufactured through laser powder bed fusion (L-PBF), as well as delves into the investigation of surface failure progression when the samples are subjected to cyclic contact stresses. This study encompasses the analysis of residual stresses, hardness, and roughness of specimens manufactured through both additive and conventional production routes. The study’s findings show that it is feasible to attain analogous surface quality when proper finishing is applied to L-PBF samples. Although, despite the comparable surface quality, the contact fatigue performance was significative lower on the AM sample when compared to the conventionally manufactured. Additionally, additive manufacturing brings up new challenges to performance by presenting a heterogeneous stress distribution and sub-superficial porosity. In conclusion, to attain a desirable surface integrity for additive manufactured parts, further research should not only focus on improving the process parametrization but should also developing finishing routes especially oriented to additive manufacturing, considering therefore how the interaction between the manufacturing processes will evolve into a desirable surface integrity state.