A Neutron Diffraction Study of the Effect Produced by the Direction of Crystal Growth on the Distribution of Residual Stresses in Austenite Steel Prisms Manufactured by Selective Laser Melting

Abstract

The effect affected by the choice of the direction of the crystal growth by selective laser melting on the distribution of residual stresses was studied on the example of initiated growing of a 20 × 20 × 70-mm prism of steel 316L. Prisms with different growth directions (along their long and short edges) have been investigated. Neutron stress diffractometry providing the measurement of all three stress tensor components in massive materials and products by a nondestructive method was used. Compressive stresses are formed in the central part of a prism in both cases. They are close to zero or transit to tensile stresses when approaching the surface. In the prism grown vertically along the long edge, tensile stresses are higher and occupy a larger volume as compared to the prism grown along the short edge. Maximum tensile stresses (~500 MPa) near the vertical prism edges are close to the ultimate yield strength of the material (~540 MPa). The maximum compressive stresses (~–400 MPa) are formed in the central part of the vertical prism.