CORROSION STUDIES ON MEDIUM CARBON STEEL WELDMENTS IN CHLORIDE ENVIRONMENT

Abstract

Welding is widely recognized as an important joining technique in engineering practice and as a consequence, welding is used in many critical applications. These welded structures are subjected to a variety of service conditions, which have an important bearing on safety and service life of structures. This study has been conducted on AlS11040medium carbon steel arc welds to in 3.5% NaCl environment in static conditions for 25, 35 and 45 days and accelerated condition for 48 hours in salt spray chamber. The specimens were welded at different values of current, keeping all other parameter constant and at different in beakers welding speeds and heat input. The welded specimens were hung 3.5M NaCl solutions in beakers. Specimens were divided in to three sets. Each set was removed from the solution after 25,35 and 45 days respectively. During this course of time crevice corrosion, pitting and uniform attack has been observed , practically around the weld. i.e. along heat affected zone and also at the corners of the plates at the above mentioned parameter, the crevice corrosion behaviour has been qualitatively observed. Moreover, micro structural changes have also contributed to the corrosion. An attempt has been made to correlate the micro structural change to crevice corrosion.