Ultra-narrow gap welding of thick section of austenitic stainless steel to HSLA steel

A substantially narrow GMAW torch nozzle head has been designed that enables narrowing down of weld groove up to a limit of just accommodating the nozzle in it where the groove wall of thick section virtually acts as a side wall of the nozzle head to produce a narrowest possible butt welding. A model of shielding gas flow dynamics and its flow rate in case of employing newly developed GMAW nozzle head has been studied at different projection angle of torch nozzle inside the narrow groove of butt joint by using ANSYS-CFX(14.5) software. The utility aspect of such a narrow nozzle head from the view point of smooth flow of shielding gas inside a close fitted ultra-narrow weld groove has also been studied. The outcome of the analytical studies has been used to produce a defect free ultra-narrow multi-pass weld by employing P-GMAW process with vertically placed electrode depositing single bead per layer in weld groove. (C) 2016 Elsevier B.V. All rights reserved.