CREVICE CORROSION STUDY OF MILD STEEL SPOT WELDS

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 condition which have an important bearing on safety and service life of structures. This study has been conducted on mild steel spot welds to observe its crevice corrosion behaviour. The specimens were welded at different values of current, keeping all other variables constant and at different values of pressure, (at other constant variables). All the welded specimens were kept 3.5 M NaCl solution. Specimens were divided into three sets. Each set was removed from the solution after 21, 28 and 35 days respectively. During this course of time, crevice corrosion attack has taken place and various corrosion products formed, particularly around the weld i.e. along heat affected zone and also along the corners of the plates. Based on microstructural changes, at the above mentioned parameters, the crevice corrosion behaviour has been qualitatively observed. Moreover, microstructural change have also contributed to the galvanic corrosion is addition to crevice corrosion. An attempt has been made to correlate the microstructural change to crevice