Development of a mathematical model to predict angular distortion in FCA welded stainless steel 301 plates

Flux Cored Arc Welding (FCAW) is an adaptable joining technique practiced extensively in industrial applications like automotive, pressure vessels, food processing equipment and general fabrication works. The process lends itself to semi or fully automatic modes and even robotic welding. This process gives the advantage of better notch toughness and effective shielding of the weld pool resulting in better mechanical strength of the final weld due to the flexibility of flux composition being used at the core of the tubular filler wire. Stainless steel 301 being austenitic in composition has excellent weldability and has extensive use in applications demanding environmental and chemical corrosion resistance. During arc welding processes the weld metal is subjected to rapid heating and cooling cycles with localized melting. This generally results in thermal stresses which have a tendency to bend the weldment across the weld line. The weldment may be rejected as a result of this angular distortion thereby causing economic losses. In cases of non rejection, the defective component might lead to catastrophic situations. Thus a study is done to predict the angular distortion. Angular distortion has been found to depend upon the input parameters used for welding. The investigative work presented is an attempt to develop a mathematical model to optimize the input variables in a way to have minimum resulting angular distortion. For a particular set of inputs, the value of angular distortion is expected to be predicted by the developed mathematical model. The adequacy of the model is checked and the graphical results are analyzed by using response surface methodology (RSM).