Efficient residual stress mitigation in additively manufactured 18Ni300 maraging steel

This study explored an effective post-heat treatment (PHT) strategy for achieving optimal residual stress relief in 18Ni300 maraging steel. The primary focus was to investigate and enhance the mechanisms underlying residual stress relief in distinct PHT processes, including aging and annealing-aging. The investigation considered various parameters, including PHT conditions, component size, and initial residual stress field. Components with cubic geometry were fabricated through laser powder bed fusion (LPBF) and subjected to both aging and annealing-aging processes. The residual stresses were extracted from these specimen variants using the contour method. The simulation involved generating the initial residual stress in the LPBF using the flash heating method and simulating the PHT process using the Arrhenius equation-based creep model. Simulations complemented and elucidated the experimental results. The validated model was employed to comprehensively investigate the intricate interrelationships among the various PHT parameters. The results indicate that the annealing-aging process leads to a substantial reduction in the residual stress compared to the aging process. Furthermore, a process map was established by considering the PHT conditions and component size. This map aids in determining the optimal PHT conditions for achieving the desired levels of stress reduction. Therefore, the present study comprehensively explored the PHT effect and its interrelated parameters, suggesting an effective PHT strategy for residual stress mitigation in LPBF, and particularly a process map that is beneficial for practical applications.