INTERGRANULAR CORROSION OF GMAW WELDMENTS OF AUSTENITIC STAINLESS STEEL IN CHLORIDE SOLUTION

Abstract

Investigations have been carried out to find the influence of various welding parameters such as current, voltage and speed on the intergranular corrosion characteristics of austenitic stainless steel parent metal, weld metal and heat affected zone in chloride environment. GMAW process was used to obtain full penetration welds in austenitic stainless steel plates with compatible solid filler wire. Standard intergranular corrosion tests were conducted to study corrosion behaviour. It was observed that, intergranular corrosion occurred predominantly in heat affected zone and along fusion line whereas weld metal and parent metal were less susceptible to intergranular attack. While varying voltage and keeping other parameters constant, intergranular corrosion was observed in heat affected zone at higher levels of voltage. This trend is same for current also. Whereas, while keeping other parameters constant and varying welding speeds, intergranular corrosion observed in heat affected zone at low levels of speed but it was lesser as compared to other welding parameters. Post weld heat treatment and thermal treatment minimizes intergranular corrosion in weldments. However intergranular corrosion was observed more in case of thermal treated weldments than post weld heat treatment