Residual Stress within Metallic Model Made by Selective Laser Melting Process

In order to improve the mechanical properties and the dimensional accuracy of the steel model produced by the selective laser melting process, the distribution of residual stress within the model is measured, and some methods for reducing the residual stress are proposed. The experimental results show that a large tensile stress remains in the surface layer of the model. Heat treatment at 600 and 700 °C for one hour reduces the residual stress effectively by about 70%. Re-scanning of laser and heating of the powder bed decrease the tensile stress by 55% and 40%, respectively.