Analysis of temperature history, distortion, and residual stress in directed energy deposition of SS316L: 3D transient model with experimental validation

Purpose The purpose of this study is to develop a thermomechanical 3D transient model to analyze distortion, temperature history and residual stresses in a production cube fabricated by directed energy deposition using SS316L. In this paper, the process parameters have been optimized based on minimum residual stress and distortion. The developed finite element model successfully predicted the distortion. Design/methodology/approach The simulation phase consists of two thermal and mechanical models. In the thermal model, the Goldak function was utilized to apply focused laser energy. A twenty-layer wall configuration was employed to optimize manufacturing parameters, including laser power, the number of layers deposited before laser interruption, dwell time and substrate thickness. Findings Distortion levels were measured in both the x and y directions, achieving average errors of 4.07% and 12.32%, respectively. It was observed that the impact of the number of deposited layers, when the laser was continuously operated, was minimal. Furthermore, a modification of 67% in substrate thickness resulted in a notable 33% decrease in residual stresses. Additionally, the interaction between substrate thickness and laser power demonstrated the most significant influence on the reduction of residual stresses. The outcomes derived from the optimization utilizing the full factorial method demonstrated a 52% improvement in the average distortion of the final component. Originality/value The exploration of the concurrent influence of the specified parameters, coupled with the application of statistical optimization techniques aimed at minimizing residual stress and distortion within the proposed model, exemplifies the innovative aspects of this research.