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.

Subject
Seams, Steel surfaces, Water, Welding, Motors, Beads, Inspection, Oxide surfaces, Defects, Pitting, Well casings, Deposit corrosion, Stainless steel
Keywords:
Stainless steels, Pitting corrosion, Welding, Heat affected zone, Sensitization
Government work published by the Association for Materials Protection and Performance (AMPP) with permission of the author(s). Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2009
GOV
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