Stress Corrosion Cracking Of Alloy Research Articles

Effect of sulphate and chloride ions on the crevice chemistry and stress corrosion cracking of alloy 600 in high temperature aqueous solutions

Concentration-pH diagrams for Alloy 600 which may suffer from crevice corrosion at 316°C in sulphate or chloride aqueous solutions have been constructed. The steam generator made of Alloy 600 is one of the key components in a PWR nuclear power plant. If steam generator degradation occurs, the nuclear power plant will be forced to shutdown or derate. Crevice corrosion of samples was studied under [SO 4 2−] ≥ 15,000 ppm, pH 25 ≤ 4 and [Cl −] ≥ 10 ppm, pH 25 ≤ 4 conditions and easily occurred in acidic media. Heavily etched surfaces resulted from the coalescence of creviced regions on the specimen. With the decrease of pH value, the critical chloride concentration for generating crevice corrosion was lowered. However, the presence of sulphate ions (8000 ppm) suppressed the anodic dissolution reactions, perhaps through the formation of sulphate salts. Their presence also increased the endurance of chloride attack on Alloy 600 by two orders of magnitude. Only in extremely acidic conditions (pH 25 ≥ 1.5) was the stress corrosion cracking of Alloy 600 observed.

Effects of heat treatments on the stress corrosion cracking of alloy 600 in high temperature waters

The effects of low temperature ageing treatments on the susceptibility of alloy 600 to stress corrosion cracking in simulated primary side nuclear reactor water have been studied by a variety of techniques. Chromium depletion at grain boundaries was assessed by Electrochemical Potentiokinetic Reactivation (EPR) and polythionic acid tests while cracking was investigated using U bend, constant strain tensile and slow strain rate tests. The susceptibility to cracking was increased by annealing at 925°C after a small amount of cold work and further enhanced by ageing for 60 h at 450°C. The activation energy for cracking is in the region of 190 kJ/mol, which indicates that marked cracking is only likely at relatively high temperatures in water.

Intergranular stress corrosion cracking of alloy 600 and x-750 in high-temperature deaerated water/steam

Intergranular stress corrosion cracking (IGSCC) has been studied in two similar nickel-base alloys, alloys 600 and X-750, in deaerated steam at elevated temperatures (380 °C). In both cases, IGSCC occurs through the nucleation, growth, and linkup of grain boundary voids rather than by grain boundary dissolution. The rate of IGSCC is much faster in both alloys when they are heat-treated so that carbon is kept in solution instead of precipitating as grain boundary carbides. This higher carbon content allows the formation of a higher methane pressure in grain boundary voids. Slip impingement on the grain boundary plays a central role in nucleating a set of voids with a spacing of about 0.2 μm. A second set of more closely spaced bubbles develops between these through the action of stress-assisted diffusion of material from the first set of bubbles.

A mechanism for hydrogen-induced intergranular stress corrosion cracking in alloy 600

Intergranular stress corrosion cracking (IGSCC) of Alloy 600 in high-temperature, deaerated water or steam has been termed “hydrogen-induced IGSCC.” We believe these cracks are initiated by the nucleation of a high density of bubbles on the grain boundary under the combined action of the applied stress and high pressure methane formed from carbon in solution reacting with hydrogen injected by corrosion. The bubbles then grow together by grain boundary diffusion to give local failure. This is supported by transmission electron microscope (TEM) observations of two-stage replicas, which show the subsurface formation of closely spaced (0.2μm) bubbles along boundaries, and their growth into fine cracks before they open to communicate with the corroding atmosphere. The kinetics are examined and shown to be in quantitative agreement with several experimental observations. This mechanism involves no grain boundary dissolution of the metal, the only role of corrosion being the injection of hydrogen at a high fugacity. It predicts an activation energy roughly equal to that for grain boundary dψusion of nickel in Alloy 600.

A mechanism for hydrogen-induced intergranular stress corrosion cracking in alloy 600

A mechanism for hydrogen-induced intergranular stress corrosion cracking in alloy 600

Alloy 800のアルカリ溶液中の応力腐食割れに及ぼす表面加工の影響

Alloy 800のアルカリ溶液中の応力腐食割れに及ぼす表面加工の影響

Stress Corrosion Cracking of Inconel Alloys and Weldments in High-Temperature Water — the Effect of Sulfuric Acid Addition

Abstract The stress corrosion cracking (SCC) susceptibilities of Alloys 600 and 690, AISI 316 NG stainless steel (SS), ASTM A508 carbon steel, and a number of compatible weld metals have been evaluated at 288 C in pure water and in pure water containing sulfuric acid additions. The sulfuric acid was added to simulate the effects of a resin release from the demineralizer system of a boiling water reactor (BWR). A combination of creviced and noncreviced slow strain rate, constant load, and crack growth rate tests were used in the evaluation. The results indicated that all of the alloys tested in the uncreviced condition were immune to cracking in the pure water environment. The presence of crevices in the pure water environment produced a susceptibility to SCC in Alloy 600, in Inconel I-82 and I-182 weld metals, and ASTM A508 steel, but not in Alloy 690. Cracking was enhanced by the addition of 1 ppm H2SO4 in slow strain rate tests (SSRTs) and constant load tests, but crack growth rates were not enhanced. All of the alloys tested in the resin intrusion environment were susceptible to cracking, except for the high chromium weld metals R-135 and Inconel I-72.

Stress corrosion cracking of Alloy 600 in high temperature water

Abstract Slow strain rate stress corrosion tests have been performed on specimens cut from four separate heats of Alloy 600 steam generator tubing. The material was tested in the mill-annealed and thermally-stabilised conditions and after various low temperature ageing treatments. Only limited cracking was observed, even for tests at 340°C, but the initiation of intergranular cracking was easier on the inner than on the outer surfaces on the tubing. Polarization data has been obtained in high-temperature water and in saturated boric acid and saturated lithium hydroxide at the atmospheric boiling points, and slow strain tests were performed at controlled potentials in these environments. Again, only very short cracks formed during the slow strain rate tests which were performed at a strain rate of about 10 −6 s −1 . The data is discussed in terms of the probable crack tip strain rates that would exist in these tests and at other strain rates. It is argued that if cracking occurs, the main role of very slow strain rate tests is to provide time for initiation and crack growth, so that cyclic loading or intermittent loading long term tests are likely to be more successful in sustaining crack growth in this alloy.

Effect of Hydrogen on the Intergranular Stress Corrosion Cracking of Alloy 600 in High Temperature Aqueous Environments

Abstract Slow strain rate tests (SSRTs) on differently shaped tensile specimens machined from two heats of Alloy 600 tubing were conducted at 350 C in deaerated aqueous solutions containing small a...

The Effect of Microstructure on the Corrosion and Stress Corrosion Cracking of Alloy 600 in Acidic and Neutral Environments

Abstract This paper presents a study of corrosion and stress corrosion cracking (SCC) of Alloy 600. The primary purpose of this work is to relate the corrosion susceptibility of the alloy after var...

Ti-6Al-4V 合金圧延材の機械的性質の異方性

When the α+β type titanium alloys are not subjected to the proper hot rolling process, the anisotropy in the microstructure appears even after the solution treatment and aging. This study was conducted to examine the anisotropy in mechanical properties of two heats (A and B) of Ti-6Al-4V alloy hot rolled plates which are subjected to the solution treatment and aging, and the mechanical anisotropy was correlated with the microstructural anisotropy. Tensile properties shows isotropic nature for both alloys. KIc and KIscc of alloy A are slightly reduced for transverse direction. On the other hand, KIc of alloy B is not reduced in T direction and KIscc is markedly increased for T direction. The KIscc in T direction is higher than KIc in the same direction. It was found that stress corrosion cracking of alloy B in transverse direction which was formed at the tip of prefatigue crack propagated with some branching along the primary α phase boundaries, leading to the apparent increase in KIscc.

Quantitative examination of stress corrosion cracking of alloy 600 in high temperature water

Stress corrosion cracking (SCC) examination of Inconel 600 steam generator tubing has continued at Brookhaven National Laboratory, using U-bends, constant load and slow extension rate tests, leading to Arrhenius plots of failure times versus inverse temperature for crack initiation and propagation. Effect of applied load can be expressed as log-log curves for failure times versus stress. Variations in environment and cold work are included in all the experiments. Microstructure and composition of oxide films on Inconel 600 surfaces were examined after exposure to pure water at 365°C, and stripping with the bromine-methanol method. Results are consistent with a mechanism of transient creep, film rupture and a mass-transport-limited anodic process.

Erratum: “Stress Corrosion Cracking of Alloys 600 and 690 and Nos. 82 and 182 Weld Metals in High Temperature Water” (Vol. 39, No. 10, October, 1983, p. 411

Erratum: “Stress Corrosion Cracking of Alloys 600 and 690 and Nos. 82 and 182 Weld Metals in High Temperature Water” (Vol. 39, No. 10, October, 1983, p. 411

Stress Corrosion Cracking of Alloys 600 and 690 and Nos. 82 and 182 Weld Metals in High Temperature Water

Abstract The relative susceptibilities of Alloy 600 and 690 base metals and I-82 and I-182 weld metals to intergranular stress corrosion cracking (IGSCC) in pure water at 288 C were evaluated. A co...

Effect of Composition and Heat Treatment on Stress Corrosion Cracking of Alloy 600 Steam Generator Tubes in Sodium Hydroxide

Abstract The resistance of Inconel alloy 600 to stress corrosion cracking in sodium hydroxide was correlated with carbon content, heat treatment, microstructure, and corrosion rate in nitric acid. ...

Effect of Heat Treatment on the Susceptibility to Stress Corrosion Cracking of Alloy 600

It was shown that a modified Huey test, i.e., a 24-h immersion in boiling 40% HNO3, is able to exactly detect the susceptibility to intergranular corrosion of Alloy 600, which is correlated with in...

Effect of Microstructure on Stress Corrosion Cracking of Alloy 600 in High Purity Water

Abstract Laboratory thermal-mechanical processing was used to produce Alloy 600 material with varying microstructures. The materials were fabricated into single U-bend specimens and tested in 343 C...

The Theory of Stress Corrosion Cracking in Alloys

(1972). The Theory of Stress Corrosion Cracking in Alloys. British Corrosion Journal: Vol. 7, No. 4, pp. 151-151.

The theory of stress corrosion cracking in alloys. herausgegeben von J. C. Scully, university of leeds, england. verlag north atlantic treaty organization, brüssel 1971

Materials and CorrosionVolume 23, Issue 7 p. 625-626 Buchbesprechungen The theory of stress corrosion cracking in alloys. herausgegeben von J. C. Scully, university of leeds, england. verlag north atlantic treaty organization, brüssel 1971 H. Speckhardt, H. SpeckhardtSearch for more papers by this author H. Speckhardt, H. SpeckhardtSearch for more papers by this author First published: Juli 1972 https://doi.org/10.1002/maco.19720230723Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume23, Issue7Juli 1972Pages 625-626 RelatedInformation

On the influence of heat treatments on the stress corrosion cracking of Al-Zn-Mg alloys

Investigation was made to examine the effects of heat treatments on the stress corrosion cracking of ternary Al-Zn-Mg alloys such as Al-4.5wt.%Zn-3wt.%Mg, Al-4.5wt.%Zn-2wt.%Mg, and Al-4.5wt.%Zn-1wt.%Mg. The results obtained were as follows.(1) The stress corrosion cracking was the most liable for the alloys aged to have the approximate maximum strength.(2) The cracking was more liable when the temperature of solution treatment was higher and the rate of quenching was higher.(3) The cracking was more liable with the increase in zinc and magnesium contents.As shown by the transmission electron microphotograph, the above results were summarized as follows : The stress corrosion cracking of alloys was more liable when the range of precipitate-free zone was narrower in the grain boundary and the precipitates was finer.