FAILURE BEHAVIOR OF STRUCTURAL SQUARE HOLLOW SECTION CORNER WELDED JOINT

Welding is a reliable and efficient joining process in which the coalescence of metals is achieved by fusion. Welding is carried out with a very complex thermal cycle which results in irreversible elastic-plastic deformation and residual stresses in and around fusion zone and heat affected zone (HAZ). Due to the presence of residual stresses in and around the weld zone the strength and life of the component is largely reduced. An application of corner joint of square hollow section (IS 4923:1997 YSt 240) of 49.5mm x 49.5mm x 2.0mm in size is welded by the Metal Active Gas (MAG) process. To know the failure behavior of square hollow section corner welded joint various load test including bending test and shear test were performed on universal testing machine (UTM). Finite element based software SolidWorks Simulation was used to model the joint and for calculation of load stresses. Residual stress value was 512MPa and 516MPa, which is in good agreement with experimental, results (X-ray diffraction (XRD) technique). Welding parameters were optimized further using finite element model in order to reduce the residual stress. Failure behavior shows that welding has good strength both in bending and shearing test and small displacements at maximum applied load. By reduction in residual stress, displacement decreases five percentages in bending test and negligible change occurs in shear test.