Showing papers on "Stress corrosion cracking published in 1969"
Journal Article•
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TL;DR: An extensive literature review as discussed by the authors covers environmental corrosion of mild steel and low alloy steels, pitting, interand transcryst, and corrosion at high temp. stress corrosion cracking of stainless steels and austenitic Mn steels.
Abstract: An extensive literature review, covering environmental corrosion of mild steel and low alloy steels, pitting, interand transcryst. stress corrosion cracking of stainless steels and austenitic Mn steels, and corrosion at high temp. A short section on corrosion prevention is included. The discussion gives a comprehensive review of the corrosion of welds in CrNi steels, with reference to heat treatment and delta-ferrite content. 266 references. -- AATA
203 citations
TL;DR: In this article, aqueous LiCl, MgCl2, and MgBr2 solutions and in ZnCl2/KCl molten salt to clarify the corrosion reactions related to stress corrosion cracking (SCC) of austenitic stainless steel and to better define environmental variables critical to the occurrence of chloride SCC.
Abstract: Electrochemical studies were made in aqueous LiCl, MgCl2, and MgBr2 solutions and in ZnCl2/KCl molten salt to clarify the corrosion reactions related to stress corrosion cracking (SCC) of austenitic stainless steel and to better define environmental variables critical to the occurrence of chloride SCC. Type 304 stainless steel electrodes were employed, with complementary SCC tests made with U-bend Type 304 stainless steel specimens. Several conclusions critical to an understanding of the mechanism of chloride SCC resulted from these investigations: (1) SCC was observed in concentrated MgBr2 solutions, (2) H2O must be present in the electrolyte, as SCC did not occur in dry molten ZnCl2/KCl, and (3) H2 evolution from corroding specimens may be facilitated by anodic polarization. Present studies do not support a model equating crack propagation with stress assisted anodic dissolution. Rather, evidence is presented that hydrogen evolution at the crack tip occurs and is a critical precursor to crack i...
72 citations
TL;DR: In this paper, the authors found that the minimum value of ςa below which no cracking was observed, ςSSC, was dependent on the relative humidity and the particular adhesive used.
Abstract: Environment assisted fracturing, or stress corrosion cracking of adhesive joints in liquid water or a humid atmosphere was shown to occur at values of applied crack extension force ςa considerably below those required for onset of opening-mode rapid fracture ςc. The minimum value of ςa below which no cracking was observed, ςSSC, was dependent on the relative humidity and the particular adhesive used. For two adhesive systems, the one with the lower hardener content and post cure temperature showed both a lower absolute value of ςSSC and a lower ratio of ςSSC to ςc. The value of ςSSC for both adhesive systems decreased as the humidity was increased. As the relative humidity approached 100%, the value of ςSSC approached its value for liquid water. Values of ςc for the two adhesives differed by a ratio of approximately 2:1. When water was introduced to the crack tip, ςc for the less tough material increased while it was not significantly changed for the tougher material.
60 citations
TL;DR: In this article, the critical applied potential in solution (−0.145v) above which, but not below, cracking occurs is shifted in the noble direction by extraneous salt additions.
Abstract: Modest additions of sodium acetate, nitrate, iodide, or benzoate to test solution boiling at 130°C are found to increase resistance to or inhibit stress corrosion cracking of 18‐8 stainless steel. The critical applied potential in solution (−0.145v) above which, but not below, cracking occurs is shifted in the noble direction by extraneous salt additions. When the shift exceeds the corrosion potential for 18‐8 in the same solution, cracking is apparently inhibited. On the other hand, salt additions, e.g., , which shift the corrosion potential in the noble direction may induce or accelerate stress corrosion cracking.The critical potential is interpreted as that value above which but not below Cl− ions adsorb on imperfection sites of plastically deforming metal in amount adequate to cause failure (stress sorption cracking). The present data do not support an electrochemical mechanism of stress corrosion cracking based on anodic dissolution of metal ions at the tip of a crack, nor the mechanism dependent on continuous cracking of a surface oxide film.
56 citations
Book•
01 Jan 1969
46 citations
01 Jan 1969
46 citations
TL;DR: In this paper, the authors studied the stress corrosion cracking of Type 304 stainless steel in 5N H2SO4 + 0.5N NaCl at room temperature by scanning electron microscopy.
Abstract: The stress corrosion cracking of Type 304 stainless steel in 5N H2SO4 + 0.5N NaCl at room temperature has been studied by scanning electron microscopy. Specimens in the form of thin sheet with two grain sizes were subjected to simple U-bend tests. Cracking was initiated mainly as a consequence of grain boundary corrosion but below the outer layer of grains cracking was mainly transgranular. Crack propagation occurred as a result of the formation of parallel tunnels across a grain. The width of tunnels was greater in the larger grain size material. The subsequent formation of the crack surface occurred partly as a result of tearing of tunnel walls because of the stress component acting normal to the fracture plane and partly as a result of lateral dissolution. Crack propagation occurred across {111} planes in the large grain material quenched from 1300 C (2372 F). Cracking results from the interaction of dislocation pile ups with the environment as a result of which transgranular dissolution occur...
44 citations
TL;DR: In this article, hydrogen permeability and delayed failure characteristics were directly correlated under cathodic and anodic polarization for 9-4-45 and 4340 high strength steels, and the concept of generalized hydrogen embrittlement mechanism for stress corrosion cracking becomes increasingly attractive, since it is apparent that increased susceptibility to delayed failure under anodic potentials does not, per se, rule out the availability of hydrogen.
Abstract: Hydrogen permeability and delayed failure characteristics were directly correlated under cathodic and anodic polarization for 9-4-45 and 4340 high strength steels. At cathodic potentials they both exhibited the usual increased susceptibility to failure with increasing cathodic potential. With increasingly anodic applied potential, the 9-4-45 displayed decreased times to failure, increased hydrogen permeability and surface pitting. The time to failure in 4340 did not respond to anodic polarization, there was no hydrogen permeation, and no pitting. The concept of a generalized hydrogen embrittlement mechanism for stress corrosion cracking becomes increasingly attractive, since it is apparent that increased susceptibility to delayed failure under anodic potentials does not, per se, rule out the availability of hydrogen.
42 citations
TL;DR: A brief survey of electrode potential measurements for the study of the corrosion of metals and alloys in the presence of aqueous solutions, molten salts and gaseous atmospheres is given in this paper.
Abstract: A brief survey is given of recent applications of electrode potential measurements for the study of the corrosion of metals and alloys in the presence of aqueous solutions, molten salts and gaseous atmospheres. Particularly considered are: (1) cathodic and anodic protection of passivable metals and alloys in the presence of chloride containing solutions; (2) pitting corrosion of copper in the presence of cold water; (3) stress corrosion cracking of titanium alloys in the presence of aqueous solutions; (4) diagrams of electrochemical equilibria in the presence of molten carbonates, as a function of the electrode potential and of log PCO2 or log O−−; (5) diagrams of chemical and electrochemical equilibria in the presence of gaseous oxygen as a function of ΔG° or the electrode potential E, and of temperature T; (6) diagrams of electrochemical equilibria of semi-conductive oxides, as a function of the electrode potential E, and of log O−−. Mention is made of the possible usefulness of these three las...
40 citations
TL;DR: In this paper, a kinetic and mass transport model was proposed for studying stress corrosion crack propagation in Ti. But the model is not suitable for the case of metal-coated Ti.
Abstract: Electrochemical kinetic and mass transport model for studying stress corrosion crack propagation in Ti
24 citations
01 Jan 1969
TL;DR: Titanium alloys stress corrosion cracking /SCC/ from metallurgical-mechanical viewpoint, discussing phase transformations, dislocation arrangements, crack propagation, etc as mentioned in this paper...
Abstract: Titanium alloys stress corrosion cracking /SCC/ from metallurgical-mechanical viewpoint, discussing phase transformations, dislocation arrangements, crack propagation, etc
TL;DR: In this article, a vanadium modification of 4340 alloy was used for stress corrosion testing of precracked specimens in a cantilever beam apparatus, and the effect of these plastic zones on the fracture paths was demonstrated.
Abstract: Stress corrosion testing of a vanadium modification of 4340 alloy was conducted using precracked specimens in a cantilever beam apparatus. Plastic zones at the crack tip were determined using optical interference measurements, and the effect of these plastic zones on the fracture paths was demonstrated. Crack propagation rates were measured for steels of varying yield strengths (140–205 ksi). Electron fractographs and photomicrographs associated with the fracture through plastic zone are presented. Crack propagation rates were shown to vary inversely with the yield strength of the steel with the overall failure time being related to both the propagation rate and the fracture toughness of the material.
TL;DR: In certain applications, stress corrosion cracking of austenitic stainless steels has occurred when these steels are subjected to tension stresses (residual and applied) and are exposed to...
Abstract: In certain applications, stress corrosion cracking of austenitic stainless steels has occurred when these steels are subjected to tension stresses (residual and applied) and are exposed to...
TL;DR: In this article, the authors examined the impact of varying levels of impurity on the mode of cracking in Ti-5Al-2.5Sn and Ti-6Al-1.5S alloys.
Abstract: The stress corrosion cracking of titanium of three different impurity levels and of Ti-5Al-2.5Sn alloy containing both low and high amounts of Fe has been examined by scanning electron microscopy. Two types of testing were employed: U-bends and dynamic tensile straining. Increasing levels of impurity resulted in a change in the mode of cracking in titanium from intergranular separation to transgranular cleavage. Both alloys exhibited transgranular cleavage. Introducing small amounts of the hydride phase in the most impure titanium resulted in (1) a larger amount of cleavage in subsequent stress corrosion tests, and (2) air fractures that were similar to stress corrosion fractures. Pre-exposure of unstressed specimens to the environment followed by fracture in air also resulted in small regions of similar fractures. Anodic dissolution superimposed on specimens during the pre-exposure period eliminated this region provided that the rate of dissolution was similar to the rate of H diffusion. A detai...
TL;DR: In this article, the effect of metal ion additions to the environment on the intergranular stress corrosion cracking (SCC) and corrosion of unalloyed titanium in a methanol-hydrochloric acid solution was investigated.
Abstract: A study has been made of the effect of additions of various metal ions to the environment on the intergranular stress corrosion cracking (SCC) and corrosion of unalloyed titanium in a methanol-hydrochloric acid solution. Separate additions to the solution of Pd, Au, Fe (ferric), and Cu (cupric) ions, in quantities ranging from 0.01 to 1000 ppm, caused substantial increases in both susceptibility to SCC and intergranular corrosion, without the resulting passivity reported for aqueous hydrochloric acid solutions. Electrochemical studies established that these increases resulted from the enhancement of the over-all cathodic process. In the absence of metal ions, the major cathodic reaction appears to be the reduction of dissolved oxygen, although another reaction, tentatively identified as the recombination of hydrogen ions, also contributes to the over-all cathodic process. Pd or Au ions deposited as metal films, detectable by X-ray techniques, and these films, once present, facilitated the recombi...
TL;DR: In this article, the relative effects of grain morphology and preferred orientation on the directional susceptibility to intergranular stress corrosion cracking of a 7075-T651 aluminum alloy plate have been conducted.
Abstract: Studies of the relative effects of grain morphology and preferred orientation on the directional susceptibility to intergranular stress corrosion cracking of a 7075-T651 aluminum alloy plate have been conducted. The role of grain morphology was found to be of paramount importance in controlling crack propagation. It was found that a slow rate of propagation along grain boundaries parallel to the applied stress accounts for the low susceptibility of longitudinally stressed specimens. The results suggest that the threshold stress for short transverse specimens approximates the low stress necessary to crack grain boundaries normal to the applied stress, and the threshold stress for longitudinal specimens approximates the high stress needed to propagate cracks along boundaries parallel to the applied stress. Preferred orientation was found to be of secondary importance when compared to the effect of grain morphology. A high degree of preferred orientation, rather than any specific slip plane orientat...
Dissertation•
01 Aug 1969
TL;DR: In this paper, the fracture characteristics of three binary Ti-Al alloys (2.5, 5, and 8 wt % Al) were investigated using electron fractography and X-ray diffraction.
Abstract: Abstract The fracture characteristics of hydrogen embrittlement (HE) in three binary Ti-Al alloys (2.5, 5, and 8 wt % Al) were investigated using electron fractography and X-ray diffraction. The de...
01 Jan 1969
TL;DR: In this article, the role of precipitate-free zone (PFZ) in the stress-corrosion cracking of a ternary Al-5.3 w/o Zn-2.5 w/O Mg alloy in aqueous chloride solutions was investigated.
Abstract: : A study was made of the role of the precipitate-free zone (PFZ) in the stress-corrosion cracking of a ternary Al-5.3 w/o Zn-2.5 w/o Mg alloy in aqueous chloride solutions. For alloys heat treated to give the same hardness (140 D.P.N.), susceptibility was found to depend on the width of the PFZ (in the range 0.04-0.35 microns), both the time to initiate and to propagate stress-corrosion cracks decreasing significantly with decreasing PFZ width. Application of small anodic currents (e.g. 0.2 mA/sq cm) reduced failure times by about two orders of magnitude, while cathodic currents inhibited failure. Fractographic studies indicated that the mode of stress-corrosion failure differs from that obtained in normal tensile fracture; no evidence for discontinuous crack propagation was found. These and other observations are discussed in terms of the proposed mechanisms of stress-corrosion cracking, and shown to be consistent with a mechanism involving localized anodic dissolution of plastically deforming solid solution within the PFZ. (Author)
TL;DR: In this paper, a theoretical treatment of a possible common mechanism is outlined on an idealized model in terms of active-passive cells, and the experimental analysis of some strict geometrical and electrochemical analogies between the mechanisms of these two forms of corrosion is presented.
01 Jan 1969
TL;DR: In this paper, it is suggested that sulfided areas are inhibitors of the combination of atomic hydrogen into molecular hydrogen, and the decreased resistance to stress corrosion cracking is attributed to hydrogen embrittlement.
Abstract: The resistance to stress corrosion cracking of AISI 4340 steel foil in 0.6M aqueous sodium chloride, acidified to pH 1.5 with hydrochloric acid, is greatly decreased by prior treatment of the specimens for short periods of time with aqueous and nonaqueous solutions of sulfur, organic and inorganic sulfides, sulfur dioxides, and the inorganic salts of sulfurousand sulfuric acids. It is suggested that this prior treatment produces sulfided areas which are inhibitors of the combination of atomic hydrogen into molecular hydrogen. The decreased resistance to stress corrosion cracking is thus attributed to hydrogen embrittlement. If the stress corrosion cracking test is made in 0.6M aqueous sodium chloride, adjusted to an initial pH of 8, the effect of a prior sulfiding treatment is small. The formation of such sulfided areas in practice result from the exposure of 4340 steels to industrial atmospheres which may contain hydrogen sulfide, sulfur dioxide, and elemental sulfur.
19 Nov 1969
31 Mar 1969
01 Jan 1969
TL;DR: In this paper, a total of 900 specimens of 40 different aluminum alloys were exposed at depths of 2,500 and 6,000 feet in the Pacific Ocean for periods of time varying from 123 to 1064 days in order to determine the effects of deep ocean environments on their corrosion resistance.
Abstract: : A total of 900 specimens of 40 different aluminum alloys were exposed at depths of 2,500 and 6,000 feet in the Pacific Ocean for periods of time varying from 123 to 1064 days in order to determine the effects of deep ocean environments on their corrosion resistance. Corrosion rates, types of corrosion, pit depths, stress corrosion cracking resistance, changes in mechanical properties and compositions of corrosion products are presented.
TL;DR: In this paper, it was shown that the intergranular corrosion of stabilized austenitic stainless steel is not accelerated when this material is explosion-clad to carbon steel, and that heat-treatment in the sensitization range causes c...
Abstract: Intergranular corrosion of stabilized austenitic stainless steel is not accelerated when this material is explosion-clad to carbon steel. Heat-treatment in the sensitization range causes c...