Showing papers on "Stress corrosion cracking published in 2000"
TL;DR: In this article, the basic mechanisms of these phenomena are discussed and the basic concepts can be found in a number of good text books and it seems worthwile to recall them in a short comprehensive paper.
278 citations
TL;DR: In this article, U-bend samples tested in 330°C pressurized water reactor water were characterized by analytical tran...Intergranular (IG) attack regions and stress corrosion cracks in Alloy 600 (UNS N06600).
Abstract: Intergranular (IG) attack regions and stress corrosion cracks in Alloy 600 (UNS N06600) U-bend samples tested in 330°C pressurized water reactor water were characterized by analytical tran...
140 citations
TL;DR: In this paper, the b-phase formation of aluminum alloys with Mg levels greater than 3.5% has been attributed to the formation of the b phase (Al.
122 citations
Journal Article•
106 citations
TL;DR: In this article, the authors investigated the susceptibility of 2205 DSS to SCC at open circuit potential and at various anodic potentials and found that the critical potential for the occurrence of SCC was coincident with its pitting potential in the above environment.
97 citations
TL;DR: The aging of water-cooled and moderated nuclear steam supply systems inevitably has given rise to many material corrosion problems of which stress corrosion cracking (SCC) is one of the most common as mentioned in this paper.
Abstract: The aging of water-cooled and moderated nuclear steam supply systems inevitably has given rise to many material corrosion problems of which stress corrosion cracking (SCC) is one of the mo...
85 citations
TL;DR: In this article, various alloys were exposed in a supercritical water oxidation (SCWO) system at 600 °C for 66.2 h. The inner oxide layer revealed the presence of numerous defects and a thickness that was proportional to the corrosion rate determined by mass loss, suggesting the oxide layer is nonprotective.
Abstract: There is a need to destroy both military and civilian hazardous waste and an urgency, mandated by public concern over traditional waste handling methodologies, to identify safe and efficient alternative technologies. One very effective process for the destruction of such waste is supercritical water oxidation (SCWO). By capitalizing on the properties of water above its critical point (374 °C and 22.4 MPa for pure water), this technology provides rapid and complete oxidation with high destruction efficiencies at typical operating temperatures. Nevertheless, corrosion of the materials of fabrication is a serious concern. While Ni and Ni-based alloys are generally considered important for severe service applications, results from laboratory and pilot-scale SCWO systems presently in operation indicate that they will not withstand some aggressive feeds. Significant weight loss and localized effects, including stress corrosion cracking and dealloying, are seen in some environments. Although exotic liners such as platinum are currently promoted as a solution to aggressive conditions, some evidence suggests the potential for corrosion control by judicious feed modification. Various alloys were exposed in a SCWO system at 600 °C for 66.2 h. After exposure, samples were coated with a thick outer salt layer and an inner oxide layer. It is considered likely that, at the high supercritical temperature employed during this test, the salt was molten and contained a substantial quantity of gas. The inner oxide layer revealed the presence of numerous defects and a thickness that is proportional to the corrosion rate determined by mass loss, suggesting the oxide layer is nonprotective. Of the alloys tested, G-30 exhibited the highest corrosion resistance. Experiments in which a C-276 tube was instrumented with thermocouples and exposed to a HCl feed indicate for this simple non-saltforming influent that there is a strong correlation between temperature and the extent and form of corrosion, with the most pronounced degradation being at high subcritical temperatures. These experiments corroborate previous results from a failure analysis for C-276, suggesting a corrosion maximum in the subcritical region. Background
79 citations
TL;DR: In this paper, the potential of using a cavitating jet to form compressive residual stress has been investigated, and the in-plane normal stresses were measured in three different directions on the surface plane using the X-ray diffraction method, allowing for the principal stresses to be calculated.
Abstract: In an attempt to strengthen the surface of materials, the potential of using a cavitating jet to form compressive residual stress has been investigated. Introducing compressive residual stress to a material surface provides improvement of the fatigue strength and resistance to stress corrosion cracking. In general, cavitation causes damage to hydraulic machinery. However, cavitation impact can be used to form compressive residual stress in the same way as shot peening. In the initial stage, when cavitation erosion progresses, only plastic deformation, without mass loss, takes place on the material surface. Thus, it is possible to form compressive residual stress without any damage by considering the intensity and exposure time of the cavitation attack. Cavitation is also induced by ultrasonic, high-speed water tunnel and high-speed submerged water jet, i.e., a cavitating jet. The great advantage of a cavitating jet is that the jet causes the cavitation wherever the cavitation impact is required. To obtain the optimum condition for the formation of compressive residual stress by using a cavitating jet, the residual stresses on stainless steel (JIS SUS304 and SUS316) and also copper (JIS C1100) have been examined by changing the exposure time of the cavitating jet. The in-plane normal stresses were measured in three different directions on the surface plane using the X-ray diffraction method, allowing for the principal stresses to be calculated. Both of the principal stresses are found changing from tension to compression within a 10 s exposure to the cavitating jet. The compressive residual stress as a result of the cavitating jet was found to be saturated after a certain time, but it starts decreasing, and finally, it approaches zero asymptotically. It could be verified in the present study that it was possible to form compressive residual stress by using a cavitating jet, and the optimum processing time could also he realized. The great difference between the water jet in water and air has also been shown in this regard.
79 citations
TL;DR: A series of experiments to determine the influence of Mg on the corrosion and electrochemical behavior of Al was conducted in this article. But the results of these experiments were limited to a single sample.
Abstract: This article summarizes a series of experiments to determine the influence of Mg on the corrosion and electrochemical behavior of Al. Magnesium is commonly added to increase the strength of lightweight nonheat treatable Al alloys. However, these alloys are susceptible to grain boundary dissolution, stress corrosion cracking, or hydrogen induced embrittlement due to changes in the alloy structure and elemental distribution during processing, welding, or in-service exposure to elevated temperatures. Auger electron spectroscopy and transmission electron microscopy measurements show that alloys having a distribution of Al3Mg2 (β phase) precipitates and segregated Mg on grain boundaries are more susceptible to cracking. To understand the roles of Mg on the cracking process we compared the corrosion potential and film formation of pure Al, Al implanted with Mg, a 7 wt % Mg–Al alloy and pure Al3Mg2 phase. The surfaces of the specimens were cleaned and prepared in a surface analysis system and transferred in a va...
69 citations
TL;DR: In this article, the recovery kinetics of rapidly scratched scars on the surface of type 304 (UNS S30400) stainless steel (SS) in a chloride solution was examined using an ampero-chronometric method.
Abstract: Repassivation kinetics of rapidly scratched scars on the surface of type 304 (UNS S30400) stainless steel (SS) in a chloride solution was examined using an ampero-chronometric method. Its ...
67 citations
TL;DR: In this article, the residual stress in a large-diameter multi-pass butt-welded pipe joint was calculated for various welding pass sequences by thermal elastic-plastic analysis using the finite element method.
Abstract: Residual stress in a large-diameter multi-pass butt-welded pipe joint was calculated for various welding pass sequences by thermal elastic-plastic analysis using the finite element method. The pipe joint used had an X-shaped groove, and the sequences of welding passes were changed. The distribution of residual stress depends on the welding pass sequences. The mechanism that produces residual stress in the welded pipe joint was studied in detail by using a simple prediction model. An optimum welding sequence for preventing stress-corrosion cracking was determined from the residual stress distribution.
TL;DR: In this paper, the effects of electrode potential and sulphate content in the water on the stress corrosion cracking (SCC) of a low alloy steel transition weld, A508-309L/308L, in PWR primary side waters at 292°C have been studied using slow strain rate testing (SSRT).
TL;DR: In this article, the effect of applied potential on the environmentally assisted cracking in 2205 duplex stainless steels (DSSs) in 26 wt% NaCl of pH 2 was investigated.
TL;DR: In this article, cold work accelerates stress corrosion cracking (SCC) growth rates in Alloy 600 (UNS N06600), and the variation in crack growth rates generated from cold-worked material has been sign...
Abstract: Cold work accelerates stress corrosion cracking (SCC) growth rates in Alloy 600 (UNS N06600). However, the variation in crack growth rates generated from cold-worked material has been sign...
Patent•
22 Dec 2000TL;DR: In this paper, a metal probe comprised of a metal which is substantially identical to that of the corrodible metal article and a transducer element attached to said probe, which is capable of projecting and receiving ultrasonic or radio frequency signals through the probe.
Abstract: A corrosion sensor and method for its use to detect and determine the, type, location, size and growth rate of corrosion of metals and the like in a corrosive environment. The corrosion sensor can distinguish between different types of corrosion such as uniform corrosion, pitting, crevice, and stress corrosion cracking. The sensor detects corrosion conditions of a corrodible metal article in a corrosive environment. It has a metal probe comprised of a metal which is substantially identical to that of the corrodible metal article and a transducer element attached to said probe, which is capable of projecting and receiving ultrasonic or radio frequency signals through the probe. The received signals indicate corrosion of the probe and hence the corrodible metal article.
TL;DR: In this article, laser-shock processing was used to reinforce surfaces by generating compressive residual stresses that has been investigated to change the surface mechanical state and modify the electrochemical properties of three commercial steels.
Abstract: Laser-shock processing or laser peening (LP) is a novel process used to reinforce surfaces by generating compressive residual stresses that has been investigated to change the surface mechanical state and modify the electrochemical properties of three commercial steels. The first part of this paper relates to experiments where LP has been applied to G10380 and G41400 steels for corrosion testing in an acid HKSO4-0.3 M solution. Only in the case of G41400 martensitic steel is a reduction of the corrosion current observed, depending on the degree of work hardening and the amplitude of compressive stresses. This indicates a small mechanochemical effect of LP, which seems to be restricted to martensitic structure. Second, the effect of LP on stress corrosion cracking (SCC) of AISI 316L stainless steel is demonstrated by static tests in MgCl2 44% – 153 °C solution. The results confirm the applicability of LP to suppress cracks on all the areas processed without occurrence of any problems in the treated-nontreated transitions zones.
Patent•
31 Jul 2000TL;DR: The laser peenmarking system as mentioned in this paper is a method and apparatus for marking components by inducing a shock wave on the surface that results in an indented (strained) layer and a residual compressive stress in the surface layer.
Abstract: The invention is a method and apparatus for marking components by inducing a shock wave on the surface that results in an indented (strained) layer and a residual compressive stress in the surface layer. One embodiment of the laser peenmarking system rapidly imprints, with single laser pulses, a complete identification code or three-dimensional pattern and leaves the surface in a state of deep residual compressive stress. A state of compressive stress in parts made of metal or other materials is highly desirable to make them resistant to fatigue failure and stress corrosion cracking. This process employs a laser peening system and beam spatial modulation hardware or imaging technology that can be setup to impress full three dimensional patterns into metal surfaces at the pulse rate of the laser, a rate that is at least an order of magnitude faster than competing marking technologies.
TL;DR: In this paper, a constant deflection device designed for use within a transmission electron microscope (TEM) was used to study the change in dislocation configuration ahead of a crack tip during stress corrosion cracking (SCC).
Abstract: A constant deflection device designed for use within a transmission electron microscope (TEM) was used to study the change in dislocation configuration ahead of a crack tip during stress corrosion cracking (SCC) of brass in water, Ti-24% Al-11% Nb alloy in methanol (CH3OH), and the initiation of SCC. In-situ tensile tests in the TEM also were carried out to assess deformation without the influence of environment. Results showed that corrosion during SCC enhanced dislocation emission, multiplication, and motion as well as produced a dislocation-free zone (DFZ). Nanocracks of SCC initiated in the DFZ or from the crack tip when the corrosion-enhanced dislocation emission and motion reached a certain condition. The action of the corrosion process prompted nanocrack propagation into a cleavage or intergranular microcrack rather than blunting into a void as seen during experiments in the TEM.
TL;DR: In this article, the general corrosion, pitting and stress corrosion cracking (SCC) resistance of 2195 plates joined by FSW was investigated for comparison purposes along with Al 2195 and Al 2219 plates joining by the variable polarity plasma arc welding method.
Abstract: The friction stir welding (FSW) process has been evaluated for application on the Al 2195 cryogenic tank of the Space Transportation System. In the present study, the general corrosion, pitting and stress corrosion cracking (SCC) resistance of 2195 plates joined by FSW was investigated. Plates of Al 2219 joined by FSW were also tested for comparison purposes along with Al 2195 and Al 2219 plates joined by the variable polarity plasma arc welding method. The general corrosion, SCC and pitting behavior of FSW AI 2195 and AI 2219 is presented and discussed.
TL;DR: In this article, the effect of static and cyclic loading conditions on the stress corrosion cracking of unidirectional glass reinforced polymer (GRP) rods used in composite high voltage insulator has been investigated.
Abstract: The effect of static and cyclic loading conditions on the stress corrosion cracking of unidirectional glass reinforced polymer (GRP) rods used in composite high voltage insulator has been investigated. A series of stress corrosion experiments have been performed on unidirectional E-glass/modified polyester composite rods. The rods have been subjected to mechanical tensile static and cyclic stresses in the presence of a nitric acid solution. The stress corrosion fracture process in the rods was monitored using acoustic emission techniques. The experimental loading conditions simulated possible in-service loadis for composite suspension insulators. The results obtained in this study showed that the brittle fracture process can be generated in the rods when subjected to relatively low tensile stresses in the presence of a nitric acid solution. The morphology of the experimentally generated brittle fracture cracks in the rods closely resemble those from in-service failed composite suspension. It has also been shown in this research that low frequency, low amplitude vibrations in tensile loads can significantly accelerate the fracture process. It appears that the brittle fracture cracks in the rods generated under cyclic loads are less planar in nature in comparison with the cracks formed under static conditions. It has also been found that the acoustic emission generated during the stress corrosion fracture process in the rods is sensitive to the placement of the transducers. However, reasonably good correlation between the stress corrosion crack growth rates and acoustic emission has been attained.
TL;DR: In this article, the influence of isolated lithium and helium atoms on the cohesive strength of an ideal grain boundary in pure nickel was investigated, and the role of these species in grain boundary embrittlement in nickel alloys was investigated.
TL;DR: In this paper, an axisymmetric solid element model was used to characterize the detailed evolution of residual stresses in a girth weld (H4) of a BWR core shroud.
01 Oct 2000
TL;DR: In this article, the deformation mechanisms at different temperatures correlated with radiation hardening were discussed in terms of deformation mechanism and possible correlations between deformation modes and previous ICC studies are discussed.
Journal Article•
TL;DR: In this article, a series of stress corrosion experiments were performed on a pultruded E-glass/epoxy composite system commonly used in high voltage composite insulators, and it was found that planar cracks formed and propagated perpendicular to the fiber direction without generating a significant degree of fiber debonding or pullout.
Abstract: A series of stress corrosion experiments were performed on a pultruded E-glass/epoxy composite system commonly used in high voltage composite insulators. The tests were performed in nitric acid solutions (pH 1.2) using constant K 1 specimens specifically designed for stress corrosion testing of unidirectional fiber-polymer matrix composites. The effect that the magnitude of the applied loads had on the stress corrosion fracture process was investigated. The process was monitored using acoustic emission (AE) techniques. It was found that when the specimens were subjected to static loads (ranging from 71.2 to 124.6 N) in the presence of nitric acid planar cracks formed and propagated perpendicular to the fiber direction without generating a significant degree of fiber debonding or pullout. In addition, for various stress intensity factors at the crack tip both the normal and log-normal distribution functions were used to model the peak amplitude data generated by stress corrosion induced fiber fracture. Both the AE data and mechanical compliance results clearly indicated that the specimens used in this project provided consistent constant K 1 conditions over the entire range of loads considered. The results from the tests performed in this project clearly demonstrate that the constant K 1 stress corrosion experiments are simple and informative evaluation methods for monitoring stress corrosion cracking in unidirectional composites.
Journal Article•
TL;DR: In this article, the surface mobility of Ag-Cd and Cu-Zn alloys was found to be strongly related to the exchange current density, i0, between the metal and the solution.
TL;DR: In this paper, the effects of impurities (Si, P, and S) in steel on environmentally assisted cracking (EAC) behavior of solution-annealed austenitic steels in PWR primary water at 325°C were investigated.
Abstract: Effects of impurities (Si, P, and S) in steel on environmentally assisted cracking (EAC) behavior of solution-annealed austenitic steels in pressurized water reactor (PWR) primary water at 325°C were investigated. The basic chemical composition of the steels was 12% Cr-28% Ni, simulating the grain boundary (GB) composition of irradiated Type 304 (UNS S30400) stainless steel. The EAC crack growth behavior of the steels was examined by performing trapezoidal wave cyclic loading testing on precracked specimens. Results showed that Si significantly affected the EAC by promoting intergranular cracking, with only 0.48% Si promoting almost fully intergranular cracking under trapezoidal wave loading; increasing the crack growth rate; and tending to make cracking easier in the near-surface region rather than in the center of specimens. Only transgranular cracking with relatively low crack growth rates took place in the steels without Si but doped with S and P, respectively. The stress corrosion cracking (...
TL;DR: In this paper, the influence of microstructural characteristics on the mechanical properties and resistance to stress corrosion cracking (SCC) of the 7050 aluminum alloy was investigated, and the proposed treatment, step-quench and aging (SQA), can significantly improve SCC resistance and attain optimum strength by controlling grain boundary and matrix microstructures.
Abstract: The influence of microstructural characteristics on the mechanical properties and resistance to stress corrosion cracking (SCC) of the 7050 aluminum alloy was investigated. The higher fraction of recrystallization would cause a larger amount of incoherent Al 3 Zr dispersoids and high-angle grain boundaries, which increases quench sensitivity and SCC susceptibility of the alloy. Therefore, both strength and SCC resistance of the cold-rolled alloy are low. On the other hand, the hot-rolled alloy has the highest strength and superior SCC resistance, as a result of the lowest fraction of recrystallization. The SCC resistance can be significantly enhanced owing to the fine grain structure obtained with the intermediate thermomechanical treatment (ITMT); however, the strength cannot be effectively improved. The proposed treatment, step-quench and aging (SQA), can significantly improve SCC resistance and attain optimum strength by controlling the grain boundary and matrix microstructures. Higher SCC resistance and strength together with much reduced aging time are obtained simultaneously with the proposed SQA(220°C/10 s or 200°C/30s) after hot-rolling, as compared to those with the conventional T73 treatment.