Showing papers on "Stress corrosion cracking published in 1975"
TL;DR: In this article, the results of stress corrosion tests with aluminum alloys that have been obtained to date with fracture mechanics techniques are reviewed. But the present and limited status of theoretical understanding of the stress corrosion cracking is outlined.
Abstract: Stress corrosion cracking of aluminum alloys is reviewed. An extensive failure analysis shows how many service failures occurred in the aerospace industry over a ten year period and what kind of alloys and stresses led to initiation and propagation of stress corrosion cracks which caused these service failures. The paper contains most of the results of stress corrosion tests with aluminum alloys that have been obtained to date with fracture mechanics techniques. Stress corrosion crack growth rate measurements are compared with the results from smooth specimen testing and it is shown that the correlation between the different test results is very satisfactory. The present and limited status of theoretical understanding of stress corrosion cracking is outlined. A major part of the paper is devoted to the results of the latest alloy development. High strength aluminum alloys of dramatically increased stress corrosion resistance are available now. In the near future, stress corrosion resistant alloys of even higher strength might become available. What is still lacking is a detailed understanding of the mechanisms by which stress corrosion cracks initiate and propagate.
308 citations
TL;DR: In this article, a review of French data showed a reversal of the usual sensitizing effect in the case of intergranular stress corrosion cracking in high temperature, deaerated water.
Abstract: Intergranular stress corrosion cracking (SCC) of Inconel 600 is of concern to the nuclear power industry. Heat exchangers in commercial nuclear systems have shown SCC in only a fraction of a percent of the tubes in high temperature water, but laboratory SCC of Ni-containing alloys have been demonstrated by several research groups. This review revolves around French data, which show a reversal of the usual sensitizing effect in the case of SCC in high temperature, deaerated water. There is no cracking reported in material first heated so as to precipitate carbides at the grain boundaries, whereas high temperature annealed conditions lead to intergranular SCC in the same laboratory experiments. Electrochemically, SCC and also grain boundary corrosion are related to the potential level of a given test; however, it is not yet understood how the different grain boundary zones in Inconel 600 corrode (with and without applied stress) so that the mechanism of cracking remains speculative. Cr-depletion is...
88 citations
TL;DR: The fracture modes, metallurgical and environmental influences, and suggested mechanisms of aqueous stress corrosion cracking in titanium alloys are reviewed in this paper, but the task of assembling a complete quantitative model is formidable.
Abstract: The fracture modes, metallurgical and environmental influences, and suggested mechanisms of aqueous stress corrosion cracking in titanium alloys are reviewed. Many observations can be rationalised, but the task of assembling a complete quantitative model is formidable.
53 citations
TL;DR: A hydrogen embrittlernent model developed by the author is adapted to stress corrosion cracking (SCC) as discussed by the authors, which leads to an equation describing the characteristic shape of the SCC velocity.
Abstract: A hydrogen embrittlernent model developed by the author is adapted to stress corrosion cracking (SCC). It leads to an equation describing the characteristic shape of the SCC velocity (v) v...
46 citations
45 citations
TL;DR: In this paper, the pitting potentials of Al4%Cu alloys with various aging structures have been measured in de-aerated 1M NaCl under conditions of controlled potential.
37 citations
TL;DR: In this paper, the initial response functions of the Fourier wave components for an infinitesimal surface notch in a single crystal sample under Mode I or tensile loading has been evaluated with respect to volume diffusion mechanisms of morphological change.
37 citations
TL;DR: The tensile properties of 304L and 310 austenitic stainless steels have been studied at 20 and 150 C (68 and 302 F) after cathodically charging with hydrogen at 100 C (212 F).
Abstract: The tensile properties of Types 304L and 310 austenitic stainless steels have been studied at 20 and 150 C (68 and 302 F) after cathodically charging with hydrogen at 100 C (212 F). The ch...
32 citations
TL;DR: In this article, the authors investigated the stress corrosion behavior in the presence of iodine vapor or chlorine gas of unirradiated, recrystallized and stress-relieved Zircaloy-4 as a function of hoop stress, test temperature and contaminant concentration.
31 citations
Patent•
31 Jan 1975
TL;DR: A bainitic steel resistant to hydrogen embrittlement, and therefore resistant to sulphide stress corrosion cracking and highly useful in the oil industry, consists essentially of 0.150 and 0.5 X %Cr + %MO + 100 X %B.
Abstract: A bainitic steel resistant to hydrogen embrittlement, and therefore resistant to sulphide stress corrosion cracking and highly useful in the oil industry, consists essentially of 0.150.35 C; up to 0.8 Mn; 0.8-1.0 Si; 1.0-2.0 Cr; 0.1-0.5 Mo; 0.2-0.6 Al; up to 0.03 P; up to 0.03 S; up to 0.05 Cu; 0.002-0.004 B; up to 0.1 Ta, balance essentially iron. The ratio Si:Mn is 1-2 and the ratio Mo-Al is 1-3. The sum of 0.5 X %Cr + %MO + 100 X %B is 1-2, preferably 1-1.5. The bainitic structure is obtained directly in the as-rolled condition by air cooling any of a wide range of plate thicknesses.
27 citations
TL;DR: In this article, the anodic behavior of AISI 304 stainless steel in 1 M hydrochloric acid solution at 25 C has been studied at different electrode potentials under static conditions and during straining at 40%/minute.
Abstract: The anodic behavior of AISI 304 stainless steel in 1 M hydrochloric acid solution at 25 C has been studied at different electrode potentials under static conditions and during straining at 40%/minute. From the potential-time curves, current-time curves, and net anodic current densities, it is concluded that a film formation process takes place under stress corrosion cracking (SCC) conditions. It is proposed that SCC in this system occurs because of a film rupture process, with cracks starting at the bare metal exposed on the slip steps. From straining experiments alone, the range of electrode potentials for SCC was estimated. Above −0.100 V, no cracking could be found because of the little difference in current density between the bare metal and the filmed metal. Below −0.200 V, no SCC was detected because of the very low rate of crack propagation (less than 10−4 mm/hour).
TL;DR: In this article, the effects of electroplated and hot-dip zinc coatings on the fracture of low-alloy steel AISI 4140 bars tempered to hardnesses in the range Rc 33 to 49 were studied.
Abstract: The effects of electroplated and hot-dip zinc coatings on the fracture of low-alloy steel AISI 4140 bars tempered to hardnesses in the range Rc 33 to 49 were studied. Either electroplated or hot-dip zinc coatings decrease resistance to stress corrosion cracking,i.e., they reduceKsc, the threshold stress intensity for stress corrosion cracking in 3.5 wt pct NaCl solution. AboveKscelectroplated-zinc coatings do not appear to affect the crack-growth rate, although the incubation period prior to the onset of crack growth is reduced. Hot-dip zinc coatings increase stress corrosion crack growth rates slightly because of the additive effect of internal dissolved hydrogen. Hot-dip zinc coatings reduce the critical stress intensity for fracture in the absence of a corrosive environment because of embrittlement by internal hydrogen which is released from traps during hot-dip coating and confined by the inter metallic coatings which form on the steel surface in the hot dip bath. A simple fracture mechanics analysis indicates that either increasing diameter or the presence of a zinc coating lowers the critical hardness at which the stress corrosion cracking of structural bolts can occur.
TL;DR: In this paper, brass specimens under stress were exposed at room temperature to 15 N aqueous ammonia solution with 8 g/1 of cupric copper predissolved and a thin oxidized film was detected by Auger spectroscopy at the leading edge of the propagating crack.
Abstract: Alloy 260 brass specimens under stress were exposed at room temperature to 15 N aqueous ammonia solution with 8 g/1 of cupric copper predissolved. This environment causes tarnishing of the brass surface and intergranular stress corrosion cracking. Scanning electron microscopy, energy dispersive X-ray analysis, and Auger electron spectroscopy were employed to study fractography, corrosion product composition and distribution within the stress corrosion crack, and fracture surface chemistry characteristic of stress corrosion cracking in this system. A thin oxidized film was detected by Auger spectroscopy at the leading edge of the propagating crack. With continued exposure to the corrosive environment, deposits form on the fracture surface, then coalesce to form a continuous tarnish film that is depleted of zinc. No bulk depletion of zinc was detected in the alloy at the stress corrosion crack leading edge. No evidence of noncrystallographic crack arrest marks was found on the intergranular fracture surface.
TL;DR: In this paper, the authors investigated the mechanism and the environment responsible for cracking of a steam turbine at Hinkley Point “A” nuclear power station and found that the cracking is due to the action of wet, high purity steam on stressed metal.
TL;DR: In this paper, the authors test a concept of controlling stress corrosion crack propagation in Al-Zn-Mg alloys through the use of minor alloying additions of elements known to retard hydrogen ion recombination.
Abstract: Studies were undertaken to test a concept of controlling stress corrosion crack propagation in Al-Zn-Mg alloys through the use of minor alloying additions of elements known to retard hydrogen ion recombination. Previous work suggested that the recombination of hydrogen ions governs the rate of anodic dissolution and, in turn, the rate of crack propagation in these alloys. Results indicated that the concept was invalid since the minor alloying additions themselves exerted a more profound influence on the grain boundary microstructure. Specifically, the microstructural features of grain boundary particle size and interparticle spacing were found to correlate with stress corrosion susceptibility. Auger electron spectroscope studies also revealed a correlation between the concentration of Zn and Mg within the precipitate-free zone and the susceptibility to cracking.
TL;DR: In this paper, stress corrosion cracking (SCC) experiments were conducted in 42% boiling MgCl2 on two Type 304L stainless steels which exhibited a duplex ferrite-austenite structure in the weld fusion zone and showed that when weldments are transverse to the principal stress axis, carbon and nitrogen contents of the alloy can be important in determining SCC susceptibility.
Abstract: Stress corrosion cracking (SCC) experiments were conducted in 42% boiling MgCl2 on two Type 304L stainless steels which exhibited a duplex ferrite-austenite structure in the weld fusion zone. Results indicate that when weldments are transverse to the principal stress axis, carbon and nitrogen contents of the alloy can be important in determining SCC susceptibility. In the material containing higher C and N concentrations, which exhibited no delta ferrite in the HAZ, SCC occurred in the grain coarsened region adjacent to the weld fusion zone. In the material with less C and N, ferrite which formed in the HAZ prevented grain coarsening and SCC occurred in the unaffected base metal. If the ferrite-austenite interphase interfaces in ferrite containing weld metal were normal to the principal stress, stress corrosion cracks initiated and propagated along the interphase interfaces. This interfacial cracking can be ascribed to sensitization of the austenite-ferrite interface as a result of non-equilibriu...
TL;DR: In this paper, it was suggested that the high rate of the intergranular stress corrosion cracking of mild steel is connected with the formation of the passive γ-Fe 2 O 3 film and its sensitivity to the depassivating action of steel constituents such as carbon.
TL;DR: In this article, it was shown that residual tensile stresses from the coining operation can have a deleterious effect on the stress corrosion susceptibility of the post-coined structure.
Abstract: The cold working process of stress coining is used to provide fatigue improvement of fastener holes in aircraft structures. The cold working produces a radial flow of the metal. The residual stresses resulting from stress coining provide protection against fatigue damage by opposing the applied tensile stresses in service at the edge of the fastener hole. However, it is shown in this paper that in addition to the compressive stresses surrounding the stress coined hole, there are tensile stresses that result from the coining operation and that these residual tensile stresses can have a deleterious effect on the stress corrosion susceptibility of the postcoined structure.
TL;DR: In this paper, the authors studied the stress corrosion cracking of carbon steels in a number of environments (nitrates, hydroxides, carbonates, chlorides and liquid ammonia) by scanning electron microscopy.
Patent•
01 May 1975TL;DR: An austenitic stainless steel immune to stress-corrosion cracking and intergranular STC cracking in both the annealed and cold worked condition is described in this article.
Abstract: An austenitic stainless steel immune to stress-corrosion cracking and intergranular stress-corrosion cracking in both the annealed and cold worked condition. The steel consists essentially of 0.005 - 0.08% carbon, 0.01 - 0.04% nitrogen, 16.0 - 20.0% chromium, 8.0 - 10.0% nickel, and 3.5 - 5.5% silicon, to form a microstructure consisting of 7 to 45 volume % delta ferrite in an austenitic matrix. The steel is further characterized by exceptional resistance to pitting corrosion and intergranular attack and good weldability and hot and cold workability.
TL;DR: In this article, a series of Ni-Cr-Fe heats with C, S, and P varied within the composition range of alloy 600 were conducted on Ni-cr-Fe powders, and the materials were in several conditions of heat treatment.
Abstract: Corrosion tests were conducted on a series of Ni-Cr-Fe heats with C, S, and P varied within the composition range of alloy 600. The materials were in several conditions of heat treatment. Stress corrosion cracking (SCC) tests were conducted in undeaerated and deaerated water and deaerated 50% NaOH, all at 316 C (600 F). Intergranular corrosion tests were conducted in boiling 65% nitric acid and ferric sulfate-sulfuric acid solutions. In 8000-hour deaerated water tests, all materials were resistant to stress corrosion cracking (SCC). In undeaerated water and in deaerated 50% NaOH, all materials showed intergranular attack. Corrosion rates in boiling 65% nitric acid and ferric sulfate-50% sulfuric acid increased with increased carbon and sulfur levels. Some of the test coupons corroded uniformly and intergranularly during the ferric sulfate-50% sulfuric acid exposure. Reducing the sulfuric acid concentration and increasing the ferric sulfate concentration caused intergranular corrosion of carbon an...
TL;DR: In this article, the influence of anodising current density, film thickness and grain orientation relative to the subsequent loading direction, and also that of oxide ageing between oxidation and sealing, was studied.
Abstract: With the object of protecting aluminium alloys against stress corrosion cracking in saline water, anodic γ1−, γ2−A12O3 and γl−, γ2−Al2O3.3H2O films were formed on aluminium−2·5 wt-% magnesium alloy specimens. The influence of anodising current density, film thickness and, above all, grain orientation relative to the subsequent loading direction, and also that of oxide ageing between oxidation and sealing, was studied. The specimens were tested under accelerated laboratory stress corrosion conditions, including the corrosive environment (1 M NaCl solution), circulation conditions and impressed anodic current. For each category of specimen, tensile stress vs specimen life (time to cracking) curves were established. Results obtained with this procedure showed that the conditions of formation of the oxides and their hydrates, and particularly the orientation of the grains, have a considerable influence on their protective properties and mechanical strength; some of these oxide or hydrate coatings were...
TL;DR: The potential of SCC increased progressively as the chloride concentration was lowered, cracking occurred at about 600 mV (with respect to Pt) with 5N NaCl, but not until about 1100 mV with 0.001 N NaCl.
Abstract: The stress corrosion cracking (SCC) of stainless steel in high temperature water was studied by anodically polarizing stressed (partially flattened), hollow thinwall Type 304 stainless steel electrodes to the point of SCC in 0.001 N to 5N NaCl at 290 C. The potential of SCC increased progressively as the chloride concentration was lowered, cracking occurring at about 600 mV (with respect to Pt) with 5N NaCl, but not until about 1100 mV with 0.001 N NaCl. On the other hand, SCC was always preceded by pitting where the current rose sharply, and the current required to produce cracking was progressively less as the NaCl concentration decreased. There was no rise in hydrogen flux through the electrode wall prior to cracking, nor any other indication of a hydrogen effect in SCC. The pitting preceding SCC was revealed by SEM to actually involve a type of filiform corrosion where chloride was concentrated under the surface oxide in filament-like occluded cells. A Cr-rich corrosion phase is formed beneat...
TL;DR: In this paper, a straining electrode test was used to determine the relative susceptibilities of various alloys to stress corrosion cracking (SCC) in a high temperature aqueous solution.
Abstract: A straining electrode test was used to determine the relative susceptibilities of various alloys to stress corrosion cracking (SCC) in a high temperature aqueous solution. The results showed that duplex alloys are generally superior to austenitic alloys, and that nickel-base alloys have the greatest resistance except in the sensitized condition.
TL;DR: In this article, the results of a test program where 25 copper alloys were exposed as stressed U-bends to two industrial atmospheres and one marine atmosphere for times up to 8 years were described.
Abstract: This paper describes the results of a test program where 25 copper alloys were exposed as stressed U-bends to two industrial atmospheres and one marine atmosphere for times up to 8 years. Many of the alloys have not failed to date. However, a number of zinc containing alloys (>20%), even in the presence of other alloying additions which normally impart resistance to stress corrosion, have failed. The industrial sites are more aggressive than the marine site, resulting in failure of more alloys and shorter stress corrosion life. Alloying effects were found to be extremely important in determining stress corrosion susceptibility and crack morphology. The results are discussed relative to the influence of environment, alloy composition, and structure on stress corrosion performance and the mechanism of stress corrosion cracking (SCC).
TL;DR: In this paper, various factors affecting the nucleation and development of corrosion pits, crevices and stress corrosion cracks in iron and steel are reviewed for the purpose of assessing the presumed correlation between pitting corrosion (PC), crevice corrosion (CC) and SCC phenomena.
Abstract: Various factors affecting the nucleation and development of corrosion pits, crevices and stress corrosion cracks in iron and steel are reviewed for the purpose of assessing the presumed correlation between pitting corrosion (PC), crevice corrosion (CC) and stress corrosion cracking (SCC) phenomena. Similarities and differences are emphasised and discussed.Some tentative recommendations for future research are given.In an appendix, some aspects of hydrogen embrittlement (HE) are reviewed in connection with the phenomena of localised corrosion (LC).
TL;DR: In this paper, the morphology of corrosive attack is studied with the aid of optical micro-coverage with the help of a micro-sensor for measurements of corrosion potentials of aluminium alloys in various heat treatments.
Abstract: Results are reported for measurements of corrosion potentials of aluminium alloys in various heat treatments. The morphology of corrosive attack is studied with the aid of optical microsco...