MODELING OF RESIDUAL STRESSES IN BUTT WELD OF STAINLESS STEEL-304 USING FINITE ELEMENT METHOD AND IT'S EXPERIMENTAL VALIDATION

Abstract

The Finite element method is one of the best numerical techniques used to analyze the complicated problems. It is element wise analysis approach to investigate the complex structures. During welding temperature of the base metal reaches above the melting point which causes the residual stresses in weldments. These stresses may lead cracking and service failure. Therefore, to avoid such type of failure, modeling of weld joint for residual stress is very important from safety point of view. The purpose of this report is to model the residual stresses and temperature distribution in weld metal and heat affected zone of Stainless Steel-304 weld joint which are used in manufacturing of engine block (ALCO) of diesel locomotive. For this study, 3-D Finite Element Analysis (FEA) ANSYS code is used for analysis of single U-butt joint of Stainless Steel-304. The data obtain from FEA was validated with experimental. Attempts were also made to study. The microstructure of weld metal, heat affected zone and base metal, Hardness, toughness, tensile properties and fracture behavior of weld joint of 304-Stainless Steel. The finite element models for weld thermal cycle and residual were successfully validated. From finite element model, it was observed that residual stress is tensile in nature in weld metal region and heat affected zone. With increasing heat input peak temperature of weld thermal cycle increased. From the study, it is clear that heat affected zone is having higher hardness than weld metal and base metal. Corrosive environment decreases, toughness of weld joint, it was found weld metal weaker than the base metal and joint strength are poor.