Assessment of autogenous Type 410S stainless steel welds in replacement steam generator tube support structures

Conference · Thu Dec 31 04:00:00 EST 1992

OSTI ID:48123

Sarver, J M ^[1]; Seeley, R R; Lees, M D ^[2]

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1. Babcock & Wilcox Co., Alliance, OH (United States)
2. Babcock & Wilcox International, Cambridge, Ontario (Canada)

To eliminate fretting wear caused by flow-induced vibration in recirculating steam generators, tubes are separated from each other by tube support lattice bars. In the U-bend portion of the tube bundle, rows of tubes are separated by fan bars that radiate from collector bars located in the straight-leg portion of the steam generator. The replacement steam generators constructed by Babcock & Wilcox International use Type 410S stainless steel with a specified maximum hardness of R{sub b} 95 for tube support lattice bars, collector bars, and fan bars. An autogenous weld is used to join the fan bar to the collector bar. Corrosion tests were conducted to assess the stress corrosion cracking (SCC) susceptibility of welded type 410S stainless steel. These tests included constant-extension-rate (CERT) tests and long-term immersion tests on 410S in various welded and heat-treated conditions. The results of this test program demonstrate that, when highly stressed, the as-welded 410S weld joints are susceptible to SCC in steam generator environments. However, highly stressed 410S autogenous welds given a post-weld heat treatment were not susceptible to SCC even under faulted steam generator operating conditions.

• OSTI ID: 48123
• Report Number(s): CONF-910808--
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
MILLSTONE-1 REACTOR
MILLSTONE-2 REACTOR
STAINLESS STEEL-410
STEAM GENERATORS
STRESS CORROSION
WELDED JOINTS