Evaluating the SCC resistance of underwater welds in sodium tetrathionate
- General Electric Corp., Schenectady, NY (United States). Corporate Research and Development
The susceptibility of welds to stress corrosion cracking (SCC) is enhanced by the surface residual tensile stresses generated by the typical welding process. However, underwater plasma transferred arc (PTA) welding has been shown to produce compressive surface residual stresses, an encouraging result if repairs of cracked boiling water reactor (BWR) components are to be made without further endangering them to SCC. This program was designed to verify that underwater PTA welds are resistant to SCC and to determine if underwater PTA welding could mitigate SCC in potentially susceptible welds. This was achieved by exposing various welds on solution annealed (SA) and SA + thermally sensitized 304 stainless steel at 25 C in a solution of 1.5 gm/liter of sodium sulfide added to 0.05M sodium tetrathionate, titrated to a pH of 1.25 with H{sub 2}SO{sub 4}. The autogeneous welds were produced using gas tungsten arc (GTA) and plasma transferred arc (PTA) welding under atmospheric conditions, and PTA welding underwater. After 1 hour of sodium tetrathionate exposure, GTA and air PTA welds exhibited SCC while the underwater PTA weld heat affected zones were more resistant. Underwater PTA welds bisecting a GTA weld eliminated the cracking in the GTA weld heat affected zone under certain conditions. The lack of IG cracking in the region influenced by the underwater PTA weld is consistent with the measurement of compressive surface residual stresses inherent to the underwater welding process.
- OSTI ID:
- 548560
- Report Number(s):
- CONF-970332-; TRN: 98:000326
- Resource Relation:
- Conference: Corrosion 97. 52. annual corrosion conference of the National Association of Corrosion Engineers: economics and performance - bridging the gap and NACExpo, New Orleans, LA (United States), 9-14 Mar 1997; Other Information: PBD: 1997; Related Information: Is Part Of Corrosion/97 conference papers; PB: [4584] p.
- Country of Publication:
- United States
- Language:
- English
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