Showing papers on "Stress corrosion cracking published in 1983"
TL;DR: In this paper, the role of HE in the SCC of Al-Mg alloys was investigated using commercial Al-4.4 wt pct Mg alloy, 5083.
Abstract: Recent studies have revealed that the mechanism of stress-corrosion cracking (SCC) of high-strength Al-Zn-Mg alloys involves both dissolution and hydrogen embrittlement (HE); moreover, under tensile-loading conditions, evidence exists that the hydrogen mechanism is dominant. In the present study, the role of HE in the SCC of Al-Mg alloys was investigated using commercial Al-4.4 wt pct Mg alloy, 5083. The susceptibility of this alloy to SCC in a saline environment was evaluated in Mode I (tension) and Mode III (torsion), using precracked fracture toughness specimens. The greater susceptibility found in Mode I indicates that HE is involved in SCC. As further evidence that HE is operating, susceptibility increased when As, a hydrogen recombination inhibitor, was added to the test solution under Mode I conditions. Issues related to the overall validity of the loading mode experiment are also addressed.
83 citations
TL;DR: In this paper, the authors demonstrate the discontinuous nature of transgranular stress-corrosion cracking (TGSCC) in brass and to account for it in terms of the dynamics of competing plastic deformation and brittle crack growth.
68 citations
TL;DR: In this paper, the authors investigated the environmental stress corrosion cracking modes of model E-glass fiber-reinforced laminates in aqueous acidic environments, under both bending and tensile loads.
53 citations
TL;DR: In this paper, the authors investigated stress corrosion cracking of GRP pultruded rods in 0.0001 to 5.0 N hydrochloric acid environments under bending and tensile loading modes and found that crack initiation takes place at exposed glass fibres in the surface of the rod and crack propagation is planar and at right angles to the rod axis.
Abstract: Stress corrosion cracking of GRP pultruded rods has been investigated in 0.0001 to 5.0 N hydrochloric acid environments under bending and tensile loading modes. Crack initiation takes place at exposed glass fibres in the surface of the rod, and crack propagation is planar and at right angles to the rod axis. Leaching of calcium and aluminium from the fibres takes place during the cracking process, and time-to-failure is dependent on the acid concentration, the stress level and the ease of access of the acid to the glass fibre surface. Possible mechanisms of crack propagation through the glass fibres and resin are discussed.
51 citations
TL;DR: In this paper, two commercially-processed Al-6Zn-2Mg alloys, 7050 and a low copper, were tested for susceptibility to embrittlement by precharged hydrogen and by simultaneous cathodic charging and straining (SET procedure).
Abstract: Two commercially-processed Al-6Zn-2Mg alloys, 7050 and a “low copper” 7050, were tested for susceptibility to embrittlement by precharged hydrogen and by simultaneous cathodic charging and straining (SET procedure). Specimens were heat treated to underaged, peak-strength aged, and overaged conditions. In 7050, the peak strength and overaged conditions were not embrittled by hydrogen, though underaged material showed marked embrittlement. All microstructures tested for the low-copper alloy were embrittled. The results agree with the microstructural rationale established through earlier work on 7075 and 2124 aluminum alloys, particularly with respect to the susceptibility of underaged material to hydrogen. As in earlier work, the extent of dislocation transport of hydrogen, and local hydrogen accumulation at grain boundaries, evidently controlled the extent and degree of brittle fracture. These three important alloys can now be ranked in the order 7050, 2124, 7075 of increasing relative susceptibility to theonset of stress corrosion cracking.
50 citations
TL;DR: These investigations suggest that the in vivo corrosion environment is more severe than a 37 degrees C Ringer's solution because of the influence of both bioelectric effects and organic constituents.
Abstract: Behavior of implant alloys exposed simultaneously to tensile stresses and corrosion environments has been examined. In the in vivo studies, a stainless steel and a titanium alloy exhibited cracklike features when loaded to the yield stress sigma y and implanted for 16 weeks. A cobalt-chromium alloy stressed beyond sigma y exhibited them in plastically deformed areas. A cobalt-chromium-nickel-molybdenum alloy appeared to be immune. In vitro samples loaded to various stress levels were immersed in Ringer's solution at 37 degrees C. Half of them were subjected to applied anodic potentials; the remaining control group was not. The applied potentials were dc potentials of magnitude similar to those generated by bioelectric effects. No attempt was made to duplicate time dependence or wave forms. Cracklike features were observed in the stainless steel and in the titanium alloy loaded to or beyond sigma y and polarized for 38 weeks. None were observed below sigma y. For the controls, no cracklike features were observed at any stress level after 53 1/2 weeks. Polarization measurements and potential versus time measurements were performed to study possible mechanisms for crack propagation. These investigations suggest that the in vivo corrosion environment is more severe than a 37 degrees C Ringer's solution because of the influence of both bioelectric effects and organic constituents. The implications of these studies for the performance of prosthetic devices is discussed.
48 citations
TL;DR: In this article, the relative susceptibilities of Alloy 600 and 690 base metals and I-82 and I182 weld metals to intergranular stress corrosion cracking (IGSCC) in pure water at 288 C were evaluated.
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...
43 citations
TL;DR: In this article, the basic concepts of fracture mechanics are presented in a logical sequence, each concept is given in a concise definition-like paragraph, and the concept of fracture toughness is presented in relation to resistance curves, dynamics, constraints, and fast-stable crack growth.
Abstract: The basic concepts of fracture mechanics are presented in a logical sequence. Each concept is given in a concise definition-like paragraph. The concepts of toughness, process zone, crack, and linear-elastic fracture mechanics are first introduced. The crack-tip characterizations, that is, stress-intensity factor, crack extension force, J integral, and crack-tip opening displacement are then discussed. The constraints in plane stress, plane strain, and three dimensions are pointed out. Various methods of evaluating the crack-tip characterizations are explained. The concept of fracture toughness is presented in relation to resistance curves, dynamics, constraints, and fast-stable crack growth. Some practical empirical fracture toughness relations are given. Then slow-stable crack growth is discussed, that is, stress corrosion cracking, fatigue cracking, corrosion fatigue, and viscous (creep) cracking. The summary concludes with the concept of fracture control plans.
41 citations
TL;DR: In this paper, the authors studied the crack behavior of 300M steel under various heat treated conditions and found that the crack growth rate was directly related to the number of constraint points and, hence, the prior austenite grain size.
Abstract: Stress corrosion cracking behavior of 300M steel under various heat treated conditions was studied. Threshold stress intensity was slightly dependent upon the martensitic substructure, the KIc value, and amounts of retained austenite. The prior austenite grain size exerted the maximum influence. The crack growth rate was directly related to the number of constraint points and, hence, the prior austenite grain size. Increasing the prior austenite grain size increased theK Iscc, although Stage II crack growth rate also increased. The actual crack growth rate in Stage II was intermittent and decreased slightly with increasing applied stress intensity.
40 citations
TL;DR: In this article, it was shown that S 4 O 6 2− and S 2 O 3 2− do not function simply as sources of sulfide to promote hydrogen permeation and embrittlement.
37 citations
TL;DR: In this article, the effects of phosphorus, tin, and molybdenum on the caustic stress corrosion cracking susceptibility of NiCrMoV rotor steels were investigated.
Abstract: This paper reports a study of the effects of phosphorus, tin, and molybdenum on the caustic stress corrosion cracking susceptibility of NiCrMoV rotor steels. Constant load tests were performed on these steels in 9M NaOH at 98 ± 1 °C at a controlled potential of either -800 mVHg/Hgo or -400 mVHg/Hgo. Times to failure were measured. The results show that at a potential of -400 mVHg/Hgo the segregation of phosphorus to grain boundaries lowers the resistance of these steels to caustic stress corrosion cracking. When molybdenum is removed from a steel that has phosphorus segregated to the grain boundaries, the steel’s resistance to stress corrosion cracking is improved. High purity alloys, both with and without molybdenum, show very good resistance to caustic cracking at this potential. At-800 mVHg/Hgo segregated phophorus has no effect; only molybdenum additions lower the resistance of the steel to caustic stress corrosion cracking. Segregated tin has little effect at either potential. Metallographic examination shows that one explanation for these results is that molybdenum and phosphorus, probably as anions precipitated from solution, aid in passivating the sides of the crack and thus help keep the crack tip sharp. This sharpness will increase the speed with which the crack will propagate through the sample. Furthermore, removal of molybdenum greatly increases the number of cracks which nucleate. This higher crack density would increase the relative area of the anode to the cathode and thus act to decrease the crack growth rate.
Patent•
18 Jan 1983
TL;DR: In this paper, the authors estimate the minimum distance necessary to produce a favorable residual stress pattern in a nuclear reactor joint, which is defined as the square root of the product of the radius of the pipe times the thickness of pipe on either side of the primary weld.
Abstract: Stress corrosion cracking 36 at a welded pipe joint 14 in service in a nuclear reactor can be controlled by the location of a overlay weld 18 over the primary weld 16, which extends axially along the pipe on either side of the primary weld 16. The overlay weld 18 is comprised of a plurality of circumferentially and continuously applied weld beads 35, 37 which extend substantially to a minimum distance necessary to produced a favorable residual stress pattern. This distance has been estimated to be the square root of the product of the radius of the pipe times the thickness of the pipe on either side of the primary weld 16.
TL;DR: In this paper, the intergranular stress-corrosion cracking (SCC) of sensitised Type 304 stainless steel has been studied using sodium thiosulphate solutions at room temperature.
TL;DR: In this article, the authors studied the SCC resistance of zirconium Grades 702, 704, and 705 in nitric acid and showed that they exhibit passive-to-transpassive transition over a broad range of acid concentrations and electrochemical potentials.
Abstract: Stress corrosion cracking (SCC) of zirconium Grades 702 (commercially pure zirconium), 704 (a Zr-1.5 Sn alloy), and 705 (a Zr-2.5 Nb alloy) in nitric acid has been studied by constant strain techniques, optical microscopy, scanning electron microscopy, and electrochemical techniques. Zirconium and its alloys, except welded Grade 705, had high SCC resistance in 70% HNO3 up to the boiling point. By avoiding high sustained tensile stresses, unwelded Grades 702 and 704 had very long time-to-failure, if not infinite, in 90% HNO3 at 30 C. The failure was transgranular cleavage or quasicleavage fracture. No zirconium hydride was detected by the anodizing method. Electrochemical results show that zirconium and its alloys exhibit passive-to-transpassive transition over a broad range of acid concentrations and electrochemical potentials.
TL;DR: In this paper, an examination of the rate of intergranular stress corrosion cracking (scc) of 3Cr-0·5Mo steel in hot 8 M NaOH solution as a function of the heat treatment of the alloy was made.
Abstract: An examination has been made of the rate of intergranular stress corrosion cracking (scc) of 3Cr–0·5Mo steel in hot 8 M NaOH solution as a function of the heat treatment of the alloy. The results show that the rate of scc is extremely sensitive to the concentration of segregated phosphorus in the grain boundaries. Analysis of the segregation levels of trace elements after the steel had been heat treated at 823 K for different times is presented.
TL;DR: In order to examine the cause of the Zircaloy PEI failure, stress corrosion cracking (SCC) experiments under different types of corrosive agents (Iodine, iron iodide, aluminum, cesium iodide and cadmium) were conducted.
TL;DR: In this article, the occurrence and severity of intergranular attack (IGA), stress corrosion cracking (SCC), and de-alloying attack in Al brass alloys have been investigated in an acidic chloride-citrate solution.
TL;DR: Stress corrosion cracking of polyvinylidene fluoride (PVDF) in sodium hydroxide solution is investigated in this article, where an explanation for the behavior of this material is provided.
Abstract: Stress corrosion cracking of poly(vinylidene fluoride) in sodium hydroxide solution is investigated. Poly(vinylidene fluoride) (PVDF) is embrittled in the presence of solutions of sodium hydroxide. Cracks developed in specimens of PVDF subjected to load and solution of NaOH. Reddish-brown deposits appear before cracks can be seen. Straining the material slightly above its yield point retards the cracking activity. An explanation for this behavior is provided.
TL;DR: In this paper, the corrosion and mechanical behavior of TiCode-12 and other titanium alloys, for use as candidate canister or overpack barriers in a high-level waste repository or test facility in salt, are reported.
Abstract: Studies on the corrosion and mechanical behavior of TiCode-12 and other titanium alloys, for use as candidate canister or overpack barriers in a high-level waste repository or test facility in salt, are reported. The corrosion behavior of TiCode-12 was evaluated as a function of: brine composition, temperature, time, pH, oxygen concentration, and gamma radiolysis. Uniform corrosion rates are in the range of 0.1 to 10 ..mu..m/yr; pitting or crevice corrosion has not yet been observed. The highly adherent, passivating titanium oxide film that provides the corrosion protection is being evaluated via electrochemical polarization and surface analytical techniques to enable modeling of the corrosion mechanism(s). An increase in the corrosion rate by a factor of about 2 was observed for sensitized TiCode-12; changes in the alloy microstructure are being analyzed in order to model this phenomenon. Alterations in the chemistry and processing procedure of TiCode-12 are being evaluated to optimize corrosion, mecahnical, and mill-producibility properties for high-level waste package applications. Slow strain rate testing of TiCode-12 revealed no apparent susceptibility to stress corrosion cracking; no significant changes in tensile properties were observed, but alterations in fracture mode were determined to be caused by internal hydrogen content. Hydrogen effects on titanium alloymore » mechanical properties and crack susceptibility are being studied. Some hydrogen embrittlement occurs at hydrogen concentrations in the range of 200 to 300 ppM by weight, but the strength of TiCode-12 is not affected at concentrations up to 1100 wppM. A TiCode-12 HLW canister-package is proposed that could provide long-term containment integrity and significantly minimize total HLW isolation system costs when compared to other waste package design concepts.« less
Patent•
15 Mar 1983TL;DR: Disclosed is an alloy eminently suited for use as a tubular product in deep, sour gas operations as discussed by the authors, which has an optimum combination of corrosion resistance, high strength in the cold worked condition and resistance to sulfide stress cracking and stress corrosion cracking.
Abstract: Disclosed is an alloy eminently suited for use as a tubular product in deep, sour gas operations. The alloy has an optimum combination of corrosion resistance, high strength in the cold worked condition and resistance to sulfide stress cracking and stress corrosion cracking. A typical alloy contains, in weight percent, 0.03 carbon, 22 chromium, 36 iron, 3 molybdenum, 1 manganese, 36 nickel, 0.60 silicon, 0.15 nitrogen, up to 3 tungsten and incidental impurities including copper, cobalt, columbium, tantalum and titanium.
TL;DR: In this article, a research program was conducted to determine susceptibility of steels used in low pressure turbine rotors of power plants to stress corrosion cracking (SCC) in LP turbines.
Abstract: This paper describes a research program conducted to determine susceptibility of steels used in low pressure (LP) turbine rotors of power plants to stress corrosion cracking (SCC) in LP tu...
Patent•
06 Jun 1983
TL;DR: The amorphous Fe alloy obtd. by solidifying the blended components by rapid cooling does not cause pitting corrosion, crevice corrosion, stress corrosion cracking and consumption or breaking due to hydrogen embrittlement, and it has high strength and superior fatigue resistance as mentioned in this paper.
Abstract: PURPOSE: To obtain an amorphous Fe alloy provided with high strength and resistance to fatigue, general corrosion, pitting corrosion, crevice corrosion, stress corrosion cracking, hydrogen embrittlement, etc., by adding Cr and P, C or B as principal components and necessary secondary components to Fe. CONSTITUTION: This amorphous Fe alloy consists of, by atom, 1W40% Cr and 7W35% one or more among P, C and B as principal components, 0.01W75% in total of one or more groups of secondary components selected from the following groups, and the balance essentially Fe. The groups are 0.01W40% Ni and/or Co, 0.01W20% one r more among Mo, Zr, Ti, Si, Al, Pt, Mn and Pd, 0.01W10% one or more among V, Nb, Ta, W, Ge and Be, and 0.01W0.5% one or more among Au, Cu, Zn, Cd, Sn, As, Sb, Bi and S. The amorphous Fe alloy obtd. by solidifying the blended components by rapid cooling does not cause pitting corrosion, crevice corrosion, stress corrosion cracking and consumption or breaking due to hydrogen embrittlement, and it has high strength and superior fatigue resistance. COPYRIGHT: (C)1984,JPO&Japio
Patent•
04 Nov 1983
TL;DR: In this paper, a Ni-base alloy is bloomed and is then subjected to the first time of hot working at ≥ 1,080°C heating temp. The end temp. of the working is made 700W800°C to disperse and precipitate uniformly and finely M 7 C 3 type carbide into the base.
Abstract: PURPOSE: To produce the titled alloy member having excellent resistance to stress corrosion cracking by subjecting the alloy member to the first time and the 2nd and succeeding times of hot working after blooming respectively under specific temp. conditions then subjecting the member to a heat treatment for stress relieving and recrystallization at a specific temp. CONSTITUTION: A high Cr-contg. Ni-base alloy is bloomed and is then subjected to the first time of hot working at ≥1,080°C heating temp. to form a perfect solid soln. The end temp. of the working is made 700W800°C to disperse and precipitate uniformly and finely M 7 C 3 type carbide into the base. The 2nd and succeeding times of hot working is accomplished at 900W1,050°C heating temp. and 700W800°C end temp. of the working to prevent solutionization of the fine M 7 C 3 type carbide. The alloy is further subjected to cold working if necessary, then to a heat treatment for stress relieving and recrystallization at 750W1,050°C to prevent spoiling the uniform structure of the fine M 7 C 3 type carbide. The member having excellent resistance to stress corrosion cracking and intergranular corrosion is thus obtd. COPYRIGHT: (C)1985,JPO&Japio
TL;DR: In this paper, the tendency of glassy Fe-40Ni-14P-6B to stress corrosion cracking (SCC) and hydrogen embrittlement (HE) in aqueous acidic media was investigated.
Abstract: The tendency of glassy Fe-40Ni-14P-6B to stress corrosion cracking (SCC and hydrogen embrittlement (HE) in aqueous acidic media was investigated. Cathodically polarized, elastically stressed specimens failed in 1 M MCl by HE, as did those immersed in aqueous polythionic acid at the free corrosion potential. Similar specimens immersed in aqueous FeCl3 at the free corrosion potential failed by SCC, as did those anodically polarized in 1 M HCl. The FeCl3 specimens were covered with an iron oxide film, and selective leaching of nickel from pits and cracks was observed. The remarkable cracking patterns observed in aqueous FeCl3 reflect the isotropic, grain -free nature of the glassy alloy surface, and are thought to throw some light upon the internal stress profile of this interesting material.
TL;DR: In this paper, the authors evaluated the SCC susceptibility of duplex stainless steel tubulars in oxidant-free NaCl/H2S solutions simulating downhole sour gas well environments.
Abstract: The stress corrosion cracking (SCC) susceptibility of duplex stainless steel tubulars in oxidant-free NaCl/H2S solutions simulating downhole sour gas well environments has been evaluated. The alloys tested had compositions of 21 to 25 pet Cr, ∼5 pct Ni, and ∼3 pct Mo and included both annealed and cold reduced products. The SCC tests were conducted in autoclaves pressured with H2S/CO2 and H2S /CO2/CH4 gas mixtures. Test specimens included a variety of statically loaded specimens (U-bends, C-rings, notched C-rings, tensiles, and precracked double cantilever beams) as well as dynamically strained specimens. SCC susceptibility increased with yield strength, comparing specimens stressed to their yield point. In Cl−/H2S solutions free of oxidants, SCC initiated under anodic (pitting corrosion) rather than cathodic conditions, similar to a Cl−/H2S synergism promoting both pitting and active corrosion. SCC susceptibility was measured over the full range of test temperatures: 23 ‡C to 288 ‡C. The composition-temperature region of SCC immunity has been partially defined and is largely dependent upon minimizing the H2S partial pressure, NaCl content, and the acidity established by the CO2 partial pressure.
01 Jan 1983
TL;DR: The grain boundaries are of great importance for material properties as mentioned in this paper, and they can induce strong changes in the mechanical and corrosion behaviour of a material, such as temper embrittlement, creep embrittlements, intergranular corrosion, stress corrosion cracking and so on.
Abstract: Most materials, metals and ceramics, are polycrystalline and contain more or less grain boundaries. The grain boundaries are of great importance for material properties. Dissolved atoms tend to segregate at grain boundaries and they can induce strong changes in the mechanical and corrosion behaviour. Some phenomena caused by grain boundary segregation of impurities in steels may be enumerated: temper embrittlement, creep embrittlement, intergranular corrosion, stress corrosion cracking and so on.
01 Jan 1983
TL;DR: In this article, the authors reviewed the use of acoustic emission (AE) techniques for studying corrosion problems and concluded that the AE method is a prommising approach to the detection and monitoring of localized corrosion in both laboratory specimens and engineering structures.
Abstract: Current theoretical and experimental research on the use of acoustic emission (AE) techniques for studying corrosion problems is reviewed. In particular, attention is given to the AE behavior of Type 304 stainless steel in aqueous environment, and a new method for analyzing corrosion, stress corrosion cracking, and corrosion fatigue in Type 304 steel is described. Results are also presented for other steels, aluminum and magnesium alloys, copper and its alloys, uranium alloys, and titanium and zirconium alloys. It is concluded that the AE method is a prommising approach to the detection and monitoring of localized corrosion in both laboratory specimens and engineering structures. Care must be taken, however, to discriminate valid AE signals from the background noise and to interpret the results correctly. 95 references.
TL;DR: A fractographic interpretation of stress corrosion cracking (SCC) of Zircaloy-2 was made through detailed scanning electron microscope (SEM) examination of cladding tubes irradiated and subjected to internal pressurization SCC tests in an iodine environment.
01 Jan 1983
TL;DR: In this paper, the equilibrium segregation of impurities deteriorates the resistance of the grain boundaries of many structural alloys to various types of intergranular failures, e.g., low-temperature fracture, creep rupture, stress corrosion cracking, fatigue cracks propagation.
Abstract: It is now recognised that many properties of metallic materials are critically affected when segregation occurs to their interfaces. The equilibrium segregation of impurities deteriorates the resistance of the grain boundaries of many structural alloys to various types of intergranular failures, e.g. low-temperature fracture, creep rupture, stress corrosion cracking, fatigue cracks propagation1,2. However in these basically multicomponent systems, the alloying elements can also segregate, and the interactions between the various components can alter their segregation pattern.
TL;DR: In this article, the authors investigated the stress corrosion behavior of commercially available glassy Fe-40 At% Ni-20 At% B alloy in aqueous solutions of ferric chloride, polythionic acid, and hydrochloric acid.
Abstract: The stress corrosion behavior of commercially available glassy Fe-40 At% Ni-20 At% B alloy was investigated. Constant strain testing was carried out in aqueous solutions of ferric chloride, polythionic acid, and hydrochloric acid. Weight loss and selective dissolution experiments at the free corrosion potential and linear polarization studies were also performed in these media. The potential dependence of crack morphology showed a progression from hydrogen embrittlement at cathodic potentials through general dissolution to stress corrosion cracking and crevice corrosion at anodic potentials. Selective leaching of nickel from pits and cracks was observed in chloride media. Crack morphology depended somewhat on surface topography.