LAUSR

Abstract In the present study, a binary component flux (50% SiO2 + 50% MoO3) has been used to join 6.67 mm thick plates of Nb stabilized austenitic stainless steel AISI 347, using activated flux tungsten inert gas (A-TIG) welding. Trials were performed to investigate the effect of the flux and the welding current on the depth of penetration of AISI 347. Microstructure studies revealed the formation of very fine, intimate skeletal delta ferrite along the centreline of the AISI 347 welds. It was corroborated from the tensile studies that the fracture had been experienced at the fusion zone of the ATIG weldments. The joint efficiency of ATIG welds of AISI 347 was ascertained to be 83.5% in the as-welded conditions. In the unpeened condition, the tensile stresses were predominated in the fusion zone. Low energy, double sided laser shock peening was carried out at the fusion zone of the ATIG weldments by varying pulse densities. There was a slight increment in the tensile properties, while varying the pulse densities. Furthermore, the trials were conducted by varying the number of shots for the optimal pulse density. The studies envisaged that on increasing the number of shots for a pulse density of 5000 pulses/cm2, the yield and tensile strength improve considerably by 11.8%, due to the accrued residual compressive stresses. X-ray diffraction sin2ψ method is employed to compute the residual stresses in the fusion zones to correlate the mechanical properties. It is attested from the present studies that the filler-less ATIG welding along with laser shock peening resulted in better mechanical properties.