Microstructural evolution and mechanical properties of 316L stainless steel using multiaxial forging

Abstract

In order to investigate the effect of multi-axial forging on microstructural evolution and mechanical properties, warm multi-axial forging (MAF) on stainless steel 316L is performed. MAF 316L stainless steel exhibits higher specific strength that is used in a wide number of applications such as in body implants. In the present study, stainless steel 316L was warm multi-axially forged at 600ºC for cumulative strains of 1.4, 2.8 and 4.2 and studied their microstructural evolution and mechanical properties. Microstructural evolution was seen using light optical microscopy and observed continuous reduction in grain size with pass. The average grain size of the material is reduced from 37 µm to 8 µm after nine pass. The hardness of the material increased due to combination of strain hardening and Hall-Petch strengthening. Fracture type is clearly visible with the help of SEM. The size of the dimples is continuously reducing with increasing pass, and peaks and valleys are formed due to the introduction of some brittleness in the material.