Showing papers on "Stress corrosion cracking published in 1972"
01 Jul 1972-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, the initiation of a crack in a specimen under tensile or compressive stresses is treated from the point of view of perturbation analysis, where a surface distortion is Fourier analyzed into a series of waves and the amplitude response of a single component of varying frequency is theoretically investigated.
Abstract: The initiation of a crack in a specimen under tensile or compressive stresses is treated from the point of view of perturbation analysis. A surface distortion is Fourier analyzed into a series of waves and the amplitude response of a single component of varying frequency is theoretically investigated. The response of the individual components yields a Griffith-type criterion for wave amplitude growth. The model is applied to alloy systems undergoing stress corrosion cracking via surface diffusion.
740 citations
TL;DR: In this paper, stress corrosion cracking is a phenomenon that is of interest to a wide range of metal users when it occurs under service conditions, often without any prior indication of impeding failure, its effect may be catastrophic.
Abstract: Introduction Stress corrosion cracking is a phenomenon that is of interest to a wide range of metal users When it occurs under service conditions, often without any prior indication of impeding failure, its effect may be catastrophic
230 citations
TL;DR: In this paper, the characteristics of nitrate and hydroxide solutions, known to promote stress corrosion cracking (SCC) in carbon steels, and from the form of potentiodynamic polariz...
Abstract: From observations of the characteristics of nitrate and hydroxide solutions, known to promote stress corrosion cracking (SCC) in carbon steels, and from the form of potentiodynamic polariz...
142 citations
01 Jan 1972
TL;DR: In this paper, the chemical compositions for commonly used high-strength aluminum-base alloys are listed and a typical application for each of these alloys is listed in Table 2 and the heat treatments for the various tempers of each of them are given in Table 3.
Abstract: High-strength aluminum alloys are of considerable importance in our technologically advanced society Perhaps the best-known application is in the aerospace industry, where the high-strength aluminum alloys are the engineer’s mainstay for rockets, spacecraft, aircraft, and hydrospace vehicles Table 1 lists the chemical compositions for the commonly used high-strength aluminum-base alloys Composition limits for several of these alloys are shown in Fig 1 Typical applications for each of these alloys are listed in Table 2 The heat treatments for the various tempers of these alloys are given in Table 3 Mechanical properties of the alloys are listed in Table 4 (Data in Tables 1–4 were obtained from Refs 1–45a) The highest-strength aluminum alloys are those based on the Al-Cu-Mg (2000 series) and Al-Zn-Mg-Cu (7000 series) alloy systems Since these alloys are the most widely used for today’s high-performance structures, this chapter will concentrate on them
125 citations
01 Jun 1972
TL;DR: The catastrophic failure of Hinkley Point ‘A’ unit No. 5 in September 1969 was the result of spontaneous brittle fracture of a shrunk-on turbine disc, initiated by stress-corrosion cracking in the crown of a keyway in the disc bore.
Abstract: The catastrophic failure of Hinkley Point ‘A’ unit No. 5 in September 1969 was the result of spontaneous brittle fracture of a shrunk-on ***l.p. turbine disc, initiated by stress-corrosion cracking in the crown of a keyway in the disc bore. Stress corrosion cracking of disc bores and keyways was also found on a number of other discs. The discs were made of 3 Cr-Mo steel and complied with normal acceptance standards, but due to temper embrittlement, their fracture toughness was low, and cracks only about 1/16 in deep in the concentrated stress field at the keyway crown were large enough to initiate brittle fracture. Investigation of the cause of the stress-corrosion cracking is being separately reported.
98 citations
TL;DR: In this paper, a study was made of metallurgical and environmental variables that could affect cracking of zircaloy stressed in tension in iodine vapour at temperatures commonly found in water-cooled reactor fuel sheaths (around 300°C).
93 citations
TL;DR: In this article, it is suggested that in those systems of metal and environment where the conditions are between those for general dissolution and complete inactivity, localised corrosion and stress may act conjointly to promote crack extension by selective attack upon compositional or structural features pre-existing in the metal, by the stress exposing relatively small areas of bare, reactive metal or by adsorption of appropriate species at sites where the energy for fracture is thereby lowered.
Abstract: Despite many attempts over the years to rationalise stress corrosion cracking in terms of a single mechanism, it is proposed that the growing body of evidence more readily supports a continuous spectrum of mechanisms. Thus, it is suggested that in those systems of metal and environment where the conditions are between those for general dissolution and complete inactivity, localised corrosion and stress may act conjointly to promote crack extension by selective attack upon compositional or structural features pre-existing in the metal, by the stress exposing relatively small areas of bare, reactive metal or by adsorption of appropriate species at sites where the energy for fracture is thereby lowered. The implication is that a change in the composition or structure of the alloy or in the characteristics of the environment may result in a change in the mechanism of cracking and indeed, in some cases, that crack extension may be the result of more than one mechanism operating.
64 citations
Book•
01 Jan 1972
TL;DR: In this article, stress corrosion testing with Precracked Specimens was performed on high strength steels and high strength aluminum alloys, including Titanium alloys. And the results showed that they were stable.
Abstract: : Contents: Fundamentals; Stress Corrosion testing with Precracked Specimens; High Strength Steels; High Strength Aluminum alloys; Titanium alloys.
60 citations
TL;DR: In this paper, it was shown that high strength (244,000 psi ultimate tensile strength) cold drawn carbon steel wire is susceptible to cracking in hydrogen sulfide solutions at room temperature at stress levels less than 1...
Abstract: High strength (244,000 psi ultimate tensile strength) cold drawn carbon steel wire is susceptible to cracking in hydrogen sulfide solutions at room temperature at stress levels less than 1...
55 citations
TL;DR: In this paper, a technique called tribo-ellipsometry was developed which simulates film rupture by abrading off the surface oxide during subsequent repassivation of the exposed surface, which allows simultaneous determination of film growth kinetics by ellipsometry and current transients during that time interval following removal of the oxide film.
Abstract: Since the susceptibility of a material to stress corrosion cracking (SCC) may be related to the rupture of a protective film and the repassivation rate of the material thus exposed, a technique, tribo-ellipsometry, has been developed which simulates film rupture by abrading off the surface oxide. During the subsequent repassivation of the exposed surface, this technique allows simultaneous determination of film growth kinetics by ellipsometry and current transients during that time interval following removal of the oxide film. The major advantage of the technique is that the ellipsometric transient allows one to determine which part of the current transient is responsible for repassivation and which part is involved in metal dissolution. The utility of the technique is demonstrated by comparing repassivation rates for a low carbon steel in a sodium nitrate solution in which the metal is susceptible to SCC to those in a sodium nitrite solution, in which it is not. Results obtained using this metho...
45 citations
TL;DR: The theory of stress corrosion cracking in alloys has been studied in this article, where the authors propose a method to solve the problem of stress-corrosion crack.
Abstract: (1972). The Theory of Stress Corrosion Cracking in Alloys. British Corrosion Journal: Vol. 7, No. 4, pp. 151-151.
01 Jun 1972
TL;DR: In this article, it was shown that in certain non-reheat turbines it is possible to generate high chemical concentrations in regions of high stress and thus to promote stress corrosion cracking.
Abstract: The further investigation was extensive and is continuing but the present account is limited to what throws light on the Hinkley Point ‘A’ incident and its immediate consequences. There were three main areas of investigation: (1) laboratory and on-site exploration of conditions for stress corrosion cracking of relevant steels; (2) a survey of all relevant rotors to explore the effects of applying a purely fracture mechanics approach in ignorance of the mechanism causing the initial crack or defect; (3) an examination of rotors withdrawn from machines of similar mechanical design and of properties deemed to be in the highest risk category.Interim conclusions have been drawn. They suggest that in certain non-reheat turbines it is possible to generate high chemical concentrations in regions of high stress and thus to promote stress corrosion cracking. The rate of propagation of such cracks is sufficient to produce critical stress intensities in discs of low fracture toughness in a region of high stress conce...
TL;DR: In this paper, the effect of temperature on failure times and critical potentials of mild steel and 0.24% C low alloy steel in a nitrate test solution, and in concentrated NaOH solution.
Abstract: The effect of temperature is reported on failure times and critical potentials of mild steel and 0.24% C low alloy steel in a nitrate test solution, and in concentrated NaOH solution. The inhibiting behavior of small additions of acetates or chlorides to the nitrate solution, and Quebracho extract to NaOH solutions are studied. Mechanism of failure appears to depend on adsorption of damaging ions on appropriate defect sites of the plastically deforming metal, followed by weakening of adjacent metal bonds.
TL;DR: In this article, the relationship between brittle delayed failure under stress, hydrogen permeation, and applied potential was examined for a high strength steel in an aerated and deaerated 3N NaCl e...
Abstract: The relationship between brittle delayed failure under stress, hydrogen permeation, and applied potential, has been examined for a high strength steel in an aerated and deaerated 3N NaCl e...
TL;DR: A recent re-evaluation of high strength martensitic stainless steels in sodium chloride solution has shown that crack growth at any applied potential can be adequately explained on the basis of a hydrogen embrittlement process as mentioned in this paper.
Abstract: Previous studies on high strength martensitic stainless steels in sodium chloride solution have attributed crack growth to (1) hydrogen embrittlement at highly cathodic applied potentials, and (2) active path dissolution (to the exclusion of hydrogen embrittlement) at open circuit and anodic applied potentials. A recent re-evaluation of cracking in this system, however, has shown that crack growth at any applied potential can be adequately explained on the basis of a hydrogen embrittlement process. In view of this recent clarification, the question arises whether hydrogen is involved in the cracking of austenitic stainless alloys where this possibility had been previously excluded on a basis similar to that applied to high strength steels. To this end, electrochemical studies have been conducted on AISI Type 304 stainless steel in lithium chloride. The data indicate that although hydrogen is evolved under conditions of corrosion at the free corrosion potential, none is absorbed into the steel dur...
TL;DR: In this paper, a long-range research program for the systematic electrochemical study of the corrosion phenomena occurring under conditions of restricted diffusion: pitting corrosion, intergranular corrosion, stress-corrosion cracking and crevice corrosion was presented.
Abstract: Generally speaking, the solutions existing within living pits and within active stress-corrosion cracks of many passive metals and alloys are locally acid, as a result of hydrolysis phenomena, and, if chloride exists in the corroding solution or in the metal, this acid is hydrochloric acid, which is particularly aggressive. This also occurs in other cases where corrosion proceeds under conditions of restricted diffusion, such as intergranular corrosion and crevice corrosion. In all these cases, a full knowledge of the electrochemical data (of a thermodynamic and kinetic nature) concerning both the behaviour of the active cavities existing in pits or cracks (anodes), which are generally acid, and the behaviour of passive areas outside these cavities (cathodes), which are generally alkaline, helps to aquire a full knowledge of the mechanism of the corrosion; it thus helps to overcome the corrosion. As a general rule, pitting corrosion, stress-corrosion cracking, intergranular corrosion and crevice corrosion may be annihilated by keeping the electrode potential below a given critical value, called the “protection potential”. This protection potential (below which pre-existing pits, cracks and crevices may not grow) should not be mistaken for the “rupture” or “pitting potential” (above which pits may be formed). This protection potential is approximately equal to the potential existing inside acid pits or cracks. Attention is given to the case of copper, iron, stainless steel, high strength steels, titanium and aluminium alloys. Emphasis is given to the usefulness of a long range research programme for the systematic electrochemical study of the corrosion phenomena occurring under conditions of restricted diffusion: pitting corrosion, intergranular corrosion, stress-corrosion cracking and crevice corrosion.
TL;DR: The fractographic changes occurring as a result of the interaction of titanium and methanol/HCl have been investigated in a long series of tests in which specimens were removed from the solution and broken in air after a range of treatments incorporating combinations of washing procedures and aging before fracture at different temperatures in different environments as discussed by the authors.
Abstract: The fractographic changes occurring as a result of the interaction of titanium and methanol/HCl have been investigated in a long series of tests in which specimens were removed from the solution and broken in air after a range of treatments incorporating combinations of washing procedures and aging before fracture at different temperatures in different environments. It is shown that the extensive transgranular striations observed, associated with regions of planar slip, arise from the influence of absorbed hydrogen during stress corrosion or oxygen during aging. Aging can cause the dispersion of the absorbed hydrogen and a complete absence of striations. Charging with hydrogen can cause their appearance. These regions occur also in Ti-5Al-2.5Sn alloy with cleavage. It is concluded that all the transgranular fracture in stress corrosion arises from absorbed hydrogen and that the occurrence of striations arises from a low energy tear process which can result in rapid stress corrosion fracture by a completel...
TL;DR: A survey of the strengths of the interactions between hydrogen and metals has been made in this paper, where the quantitative criterion for deciding whether flow or cleavage will prevail is the ratio of the appropriate glide plane's surface energy to the cleavage surface energy.
Abstract: Small changes in surface environments can change the energy needed to create a surface shear step. Increases in this energy tend to shift a delicate balance between glide and cleavage initiation at a crack tip. By inhibiting plastic deformation this causes an increased tendency for cleavage. Thus a material that is ductile in a vacuum can become quite brittle in the presence of certain surface-active environments, particularly atomic hydrogen. The quantitative criterion for deciding whether flow or cleavage will prevail is the ratio of the appropriate glide plane's surface energy to the cleavage plane's surface energy. A survey of the strengths of the interactions between hydrogen and metals has been made. Throughout the periodic table strong diatomic interactions occur. At solid surfaces the interactions remain strong although they are somewhat weaker than for diatoms. In solid hydrides they tend to be much weaker or non-existent. Thus the strength of the interaction depends on the metal-metal d...
Patent•
30 Jun 1972
TL;DR: An aluminum base alloy of the aluminum-zinc-magnesium-copper-chromium type with specially controlled composition limits is provided as a sheet or plate type product having the high strength and good resistance to stress corrosion cracking normally associated with this type of alloy but also having exceptional resistance to tearing.
Abstract: An aluminum base alloy of the aluminum-zinc-magnesium-copper-chromium type with specially controlled composition limits is provided as a sheet or plate type product having the high strength and good resistance to stress corrosion cracking normally associated with this type of alloy but also having exceptional resistance to tearing. Certain prescribed fabrication procedures including thermal treatments are preferably followed in producing the improved product.
TL;DR: In this paper, the authors show that the failure of ferritic 18% chromium stainless steels in solution depends on nickel content (0−8%) as well as on heat treatment and cold work.
Abstract: Stress corrosion cracking of ferritic 18% chromium stainless steels in solution depends on nickel content (0–8%) as well as on heat‐treatment and cold work. Maximum susceptibility occurs at 2% Ni; alloyed manganese has a small effect; molybdenum can be detrimental. Rolling direction has little or no effect on failure times of ferritic 18–8, contrary to failure by hydrogen cracking, indicating different mechanisms of failure. Whether or not failure occurs depends on the relation of critical to corrosion potentials for all but the lowest nickel alloys. Hence galvanic couples can be useful or damaging. The results are not readily explained in terms of electrochemical dissolution or brittle oxide films. A mechanism is favored based on adsorption of Cl− ions on appropriate surface imperfection sites.
01 Jan 1972
15 Jun 1972-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: The effect of stress history on stress corrosion cracking of AISI 4340 steel in an aqueous environment has been studied with the use of double-cantilever beam specimens as discussed by the authors.
Abstract: The effect of stress history on stress corrosion cracking of AISI 4340 steel in an aqueous environment has been studied with the use of double-cantilever beam specimens. The stress history effect was found to influence the incubation time period with changes in the stress intensity. When the stress intensity was decreased, the incubation time period was dependent on the △K and finalK f during stress corrosion testing. When the stress intensity was increased, the incubation time period was independent of the applied stress intensity. However, the stress history effect did not influence the steady-state crack growth rates. In this report, the stress history effect is explained by using the hydrogen embrittlement mechanism.
Patent•
20 Jul 1972TL;DR: An aluminum base alloy containing zinc, copper and magnesium together with manganese and with specially controlled composition limits exhibits very high strength when thermally treated to a condition having high resistance to stress corrosion cracking.
Abstract: An aluminum base alloy containing zinc, copper and magnesium together with manganese and with specially controlled composition limits exhibits very high strength when thermally treated to a condition having high resistance to stress corrosion cracking. Improved products of the alloy also exhibit low quench sensitivity and, accordingly, high strength even in very thick sections. A special aging treatment produces the optimum combination of strength and resistance to stress corrosion cracking properties.
TL;DR: In this article, the authors examined the stress-corrosion cracking of a high purity Al-6Zn-3Mg alloy in aseries of tests employing constant strain, constant strain-rate and plane strain constant load conditions in a range of aqueous environments.
TL;DR: In this article, an up-to-date review of the STRESS CORROSION CRACKing performance of high-strength ALUMINUM alloys is presented.
Abstract: AN UP TO DATE REVIEW OF THE STRESS CORROSION CRACKING PERFORMANCE OF WROUGHT HIGH STRENGTH ALUMINUM ALLOYS IS PRESENTED. SPECIAL EMPHASIS IS PLACED ON FACTORS OF MICROSTRUCTURE AND ITS DIRECTIONALITY AND THE EFFECT OF ANCILLARY ALLOYING ELEMENTS AND ENVIRONMENTAL FACTORS. EXAMPLES OF TYPICAL SERVICE PROBLEMS ENCOUNTERED WITH STRESS CORROSION CRACKING OF HIGH STRENGTH ALUMINUM ALLOYS ARE DESCRIBED ALONG WITH MEANS OF COMBATING THEM, SUCH AS PEENING, COATINGS, OR THE USE OF SPECIAL STRESS CORROSION RESISTANT ALLOYS.
TL;DR: In this article, the authors examined the existing theories of initiation and propagation of stress corrosion cracking (SCC) with particular reference to their applicability to steels in caustic solutions.
Abstract: The existing theories of initiation and propagation of stress corrosion cracking (SCC) are examined with particular reference to their applicability to steels in caustic solutions. The ele...
01 Jan 1972
TL;DR: The fracture load of the specimen in air was 7820 lb. This value provides a reference for experiments subsequently performed in a hydrogen atmosphere as discussed by the authors, where the fracture load was calculated using the same geometry and heat treated identically.
Abstract: Fatigue cracked 4340 steel specimens were austenized and oil quenched to hardness 42 R . All specimens are WOL type [9]; thickness is 1/4 in, and overall c~ck length is 2.03 ± 0.02 in. All the specimens are of the same geometry and were heat treated identically. The fracture load of the specimen in air was 7820 lb. This value provides a reference for experiments subsequently performed in a hydrogen atmosphere.