Caustic stress corrosion cracking of Inconel-600, Incoloy-800, and Type 304 stainless steel

Journal Article · Mon Mar 01 04:00:00 EST 1976 · Nucl. Technol., v. 28, no. 3, pp. 388-397

OSTI ID:4055000

Theus, G J

High-temperature electrochemical tests have resulted in the stress corrosion cracking of Inconel-600 and Incoloy-800 (registered trademarks, International Nickel Company), and Type 304 stainless steel in caustic solutions. Results show that stress corrosion cracking of these alloys can be prevented or accelerated by varying their electrochemical potential. To a certain extent, the same effect can be achieved by altering the gas atmosphere above the test solution from a pure nitrogen cover gas to a mixture of 5 percent H$sub 2$ and 95 percent N$sub 2$. The effect of the cover gas can then be negated by adjusting the specimen's electrochemical potential either to cause or to inhibit stress corrosion cracking. Some specifics of the test results reveal that in deoxygenated caustic solutions, Inconel-600 cracks intergranularly at mildly anodic potentials; Incoloy-800 cracks transgranularly at reduced potentials (at or near the open circuit potential) and intergranularly at highly oxidizing potentials; and cracking is mixed (transgranular/intergranular) for Type 304 stainless steel at or near the open circuit potential. The severity of cracking for both Inconel-600 and Incoloy-800 in deoxygenated caustic solutions is reduced by giving the materials a simulated post-weld heat treatment (1150$sup 0$F for 18 h). Test results on Inconel-600 show that high-carbon (0.06 percent) material cracks less severely than low-carbon (0.02 percent) material, in both the simulated post-weld heat-treated condition and the mill-annealed condition. (auth)

• Research Organization: Babcock and Wilcox Co., Alliance, OH
• NSA Number: NSA-33-028184
• OSTI ID: 4055000
• Journal Information: Nucl. Technol., v. 28, no. 3, pp. 388-397, Journal Name: Nucl. Technol., v. 28, no. 3, pp. 388-397; ISSN NUTYB
• Country of Publication: United States
• Language: English

Related Subjects

*INCOLOY 800-- STRESS CORROSION
*INCONEL 600-- STRESS CORROSION
*NUCLEAR POWER PLANTS-- STEAM GENERATORS
*STAINLESS STEEL-304-- STRESS CORROSION
*STEAM GENERATORS-- STRESS CORROSION
220200* --Nuclear Reactor Technology--Components & Accessories
AQUEOUS SOLUTIONS
CORROSIVE EFFECTS
COVER GAS
CRACKS
HIGH TEMPERATURE
HYDROGEN
MIXTURES
N50210 --Metals
Ceramics
& Other Materials--Metals & Alloys--Corrosion & Erosion & Surface Phenomena
N79200* --Reactors--Reactor Components & Accessories
NITROGEN
SODIUM HYDROXIDES