Stress corrosion cracking of Inconel 600 tubing in deaerated high temperature water

Technical Report · Fri Jun 01 04:00:00 EDT 1979

DOI:https://doi.org/10.2172/6018096· OSTI ID:6018096

Bulischeck, T S; Park, Y S; van Rooyen, D

Inconel 600 will undergo stress corrosion cracking (SCC) at grain boundaries when subjected to a high stress and exposed to water without oxygen at high temperature. Very few service failures have occurred but extensive intergranular cracking has also occurred in plants that experienced denting. All of these cracks were from the primary side. The process of denting produced high strains and stresses in the tubing, as well as slow strain rates during deformation. The literature is silent on effects of slow strain rates or cyclic stresses on SCC of Inconel 600 in deaerated, high temperature aqueous media such as pure or primary water. Because of the importance of avoiding primary-to-secondary leaks through the Inconel 600 pressure boundary, a research program was started at BNL in an attempt to improve the qualitative and quantitative understanding of factors influencing SCC in deaerated high temperature aqueous media. These data also predict service performance under given sets of conditions. Preliminary results which indicate that intergranular SCC is produced quite readily in some heats of tubing when exposed at (a) constant deflection, (b) when slightly cold worked and subjected to straining at low rates, (c) when subjected to slow cyclic stress, or (d) when the electrochemical potential of stressed pieces is controlled. Cracking has now been produced in Inconel 600 under conditions that had not been examined and reported before. First trends of temperature dependence of SCC are discussed. Some tentative correlations are made with microstructural variables, although a simple relationship with such structure or prior processing has not been defined. Heating at 700/sup 0/C for about 15 hours improved the SCC resistance dramatically. Future tests will include primary and secondary water ingredients and some impurities.

• Research Organization: Brookhaven National Lab., Upton, NY (USA)
• DOE Contract Number: EY-76-C-02-0016
• OSTI ID: 6018096
• Report Number(s): NUREG/CR-0858; BNL-NUREG-51027
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220200 -- Nuclear Reactor Technology-- Components & Accessories
36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
BOILERS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CORROSION
CRACKS
CRYSTAL STRUCTURE
FAILURES
GRAIN BOUNDARIES
HEAT TREATMENTS
HIGH TEMPERATURE
HYDROGEN COMPOUNDS
INCONEL 600
INCONEL ALLOYS
IRON ALLOYS
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ALLOYS
OXYGEN COMPOUNDS
STEAM GENERATORS
STRAIN RATE
STRESS CORROSION
STRESSES
TESTING
TUBES
VAPOR GENERATORS
WATER