A site investigation was conducted on corrosion damage to stainless steel alloy 316 Ti (UNS S31635) motor
pump casings installed in deep fresh water wells. The damage consists of full-wall perforation, localized pitting
and crack like attack. The corrosion attack was observed in the weld area and the heat affected zone (HAZ) of the
motor casing longitudinal seam weld. The investigation revealed that small anodic sites were formed on the motor
casing surfaces close to the seam weld as a result of poor welding and lack of post treatment. This is confirmed
through a comparison of the same material welded using a good welding practice and adequate post treatment and
installed in a similar environment. This paper presents the corrosion failure investigation and outlines measures to
avoid such failures including precautions to be taken during welding of stainless steel alloys.
Keywords: Stainless steels, Pitting corrosion, Welding, Heat affected zone, Sensitization