Effect of welding parameters on pitting corrosion rate of pulsed current micro plasma arc welded AISI 304L sheets in 1N HCl

Austenitic stainless steel sheets have gained wide acceptance in the fabrication of components, which require high temperature resistance and corrosionresistance such as metal bellows used in expansion joints in aircraft, aerospace and petroleum industries. In the case of single pass welding of thinner sectionsof this alloy, Pulsed Current Micro Plasma Arc Welding (PCMPAW) has been found beneficial due to its advantages over the conventional continuouscurrent process. This paper highlighted development of empirical mathematical equations using multiple regression analysis, correlating variousprocess parameters to pitting corrosion rates in PCMPAW of AISI 304L sheets in 1 Normal HCl. The experiments were conducted based on a fivefactor, five level central composite rotatable design matrix. The model adequacy was checked by Analysis of Variance (ANOVA). The main effectsand interaction effects of the welding process parameters on pitting corrosion rates of the welded joints were studied using surface and contour plots. From the contour plots, it was understood that peak current was the most influencing factor on the pitting corrosion rate. The optimum pitting corrosion rate was achieved at peak current of 6 Amperes, base current of 4 Amperes, pulse rateof 40 pulses/second and pulse width of 50 %

Keywords:

AISI 304L , Pulsed current , Micro plasma arc welding , Pitting corrosion