Galvanic effects accelerate crevice corrosion of type 316L SS flanges coupled to 6% Mo alloy. [Stainless Steel]
- Corrosion Testing Labs., Inc. (United States)
A service water system underwent a material replacement program in recent years. The service was a once-through system fed from the Delaware River. The original type 316L stainless steel (SS) and cement-lined carbon steel were replaced with 6% Mo alloy AL-6XN (UNS N08367). The majority of the system was 6% Mo piping connected to type 316L SS valves via gasketed flanges. During several years of operation, plant personnel observed localized crevice corrosion on the flange-face areas of the type 316L SS (UNS S31603) flanges. This area typically contains an insulation gasket material (a fibrous bound elastomeric material) that is sandwiched between flange joints. Galvanic effects, caused by the mixed alloy construction (i.e., type 316L SS to alloy 6% Mo), may be accelerating the observed crevice corrosion of type 316L SS. This possibility was of significant concern, and flange isolation kits typically used for isolating cathodic protection systems or dissimilar metals were being used. However, the plant grounding system caused the isolated flanges to have zero electrical resistance between them.
- OSTI ID:
- 6175332
- Journal Information:
- Materials Performance, Journal Name: Materials Performance Vol. 38:6; ISSN MTPFBI; ISSN 0094-1492
- Country of Publication:
- United States
- Language:
- English
Similar Records
Crevice corrosion of stainless alloys in liquid waste environment of the nuclear power plant
Gasket materials and other factors influencing the crevice corrosion resistance of stainless steel flanges
Related Subjects
320106 -- Energy Conservation
Consumption
& Utilization-- Building Equipment-- (1987-)
36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
AUSTENITIC STEELS
AUXILIARY SYSTEMS
AUXILIARY WATER SYSTEMS
BENCH-SCALE EXPERIMENTS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-MOLYBDENUM STEELS
CHROMIUM-NICKEL STEELS
CHROMIUM-NICKEL-MOLYBDENUM STEELS
CORROSION
CREVICE CORROSION
DELAWARE RIVER
ELECTROCHEMICAL CORROSION
HIGH ALLOY STEELS
IRON ALLOYS
IRON BASE ALLOYS
MOLYBDENUM ALLOYS
NICKEL
RIVERS
STAINLESS STEEL-316L
STAINLESS STEELS
STEEL-CR17NI12MO3-L
STEELS
SURFACE WATERS