Flow-accelerated corrosion behavior of SA106 Gr. C weldment

Abstract

Chemical and geometrical effects of weld on flow-accelerated corrosion (FAC) of SA106 Gr.C low alloy steel pipe was investigated using rotating cylinder electrode in 3.5-wt% sodium chloride solution and simulated feedwater of nuclear power plants. Polarization tests and weight loss tests were conducted at rotating speed of 2000 rpm (3.14 m/s) with variation of chemical and geometric parameters. The results showed that the chemical effects were relatively larger than the geometrical effects, and the welded parts became local anode and preferentially corroded, which was explained by the differences between microstructural and compositional parameters. On the other hand, under active corrosion conditions, the heat affected zone was severely corroded and microstructural effects were dominant.