Caustic stress corrosion cracking studies at 288 C (550 F) using the straining electrode technique--comparison of Alloy 600, Alloy 800, and Type 304 stainless steel
Constant pull rate tests were conducted on tensile specimens of Inconel Alloy 600, Incoloy Alloy 800, and Type 304 stainless steel in deaerated 10% NaOH solution at 288 C (550 F) with a cover gas of 5% H/sub 2/ in N/sub 2/. The pull rate used for most experiments was 3.3 x 10/sup -6/ cm/s, which corresponds to an initial strain rate of 3 x 10/sup -6/ s/sup -1/. The electrical potential of the specimens was controlled by a potentiostat using a nickel wire as a hydrogen reference electrode. Under open circuit conditions, Type 304 stainless steel specimens cracked rapidly, but Alloys 600 and 800 specimens exhibited only ductile fracture. However, cracks readily formed in Alloy 800 specimens at potentials in the +50 to +300 mV range and in Alloy 600 specimens at potentials in the +150 to +250 mV range. Scanning electron microscope (SEM) photographs of some of the cracked specimen surfaces showed the transition from ductile to brittle fracture as a consequence of changes in the specimen's electrical potential. Longitudinal metallographic cross sections also revealed the grain structure and the mode of cracking. They showed that the cracks were intergranular in Alloy 600 and Type 304 stainless steel specimens, and were transgranular in Alloy 800 specimens.
- Research Organization:
- Babcock and Wilcox Co., Alliance, OH
- OSTI ID:
- 6427484
- Journal Information:
- Corrosion; (United States), Vol. 34:6; Conference: Corrosion/77 meeting, San Francisco, CA, USA, Mar 1977
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
22 GENERAL STUDIES OF NUCLEAR REACTORS
CHLORIDES
CORROSIVE EFFECTS
INCOLOY 800
STRESS CORROSION
INCONEL 600
SODIUM HYDROXIDES
STAINLESS STEEL-304
STEAM GENERATORS
ANNEALING
CHEMICAL COMPOSITION
CRACKS
CRYSTAL STRUCTURE
ELECTRIC POTENTIAL
FRACTURES
GRAIN BOUNDARIES
HEAT TREATMENTS
PHYSICAL PROPERTIES
STRAIN RATE
ALKALI METAL COMPOUNDS
ALLOYS
BOILERS
CHEMICAL REACTIONS
CHLORINE COMPOUNDS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION
CORROSION RESISTANT ALLOYS
FAILURES
HALIDES
HALOGEN COMPOUNDS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HYDROGEN COMPOUNDS
HYDROXIDES
INCOLOY ALLOYS
INCONEL ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ALLOYS
OXYGEN COMPOUNDS
SODIUM COMPOUNDS
STAINLESS STEELS
STEELS
VAPOR GENERATORS
360105* - Metals & Alloys- Corrosion & Erosion
360102 - Metals & Alloys- Structure & Phase Studies
360104 - Metals & Alloys- Physical Properties
220200 - Nuclear Reactor Technology- Components & Accessories