Showing papers on "Stress corrosion cracking published in 1994"
TL;DR: Although intergranular stress corrosion cracking (IGSCC) of high-pressure gas pipelines has been known for more than 20 years, a transgranular form (TGSCC) was detected more recently as discussed by the authors.
Abstract: Although intergranular stress corrosion cracking (IGSCC) of high-pressure gas pipelines has been known for more than 20 years, a transgranular form (TGSCC) was detected more recently. Inst...
246 citations
TL;DR: In this article, the authors assess from available data whether irradiation in PWR primary water can adversely affect the properties of stainless steels due to irradiation assisted stress corrosion cracking (IASCC).
225 citations
TL;DR: In this paper, a review paper examines mechanisms controlling IGSCC in selected LWR components, focusing on identifying material microstructures and microchemistries which promote susceptibility to premature failure.
168 citations
31 Mar 1994-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a geometric model of crack propagation through active intergranular paths is used to evaluate the potential effects of σ grain boundary fraction and grain size on inter-granular cracking.
Abstract: Theoretical and experimental results are presented, with the primary objective of improving the resistance of convectional polycrystalline alloys to intergranular degradation phenomena, through the application of grain boundary design and control. Geometric considerations are discussed, which show that, as a consequence of both energetic and crystallographic constraints associated with twinning, a grain boundary character distribution (GBCD), consisting entire of low σ grain boundaries, is attainable. A geometric model of crack propagation through active intergranular paths is used to evaluate the potential effects of σ grain boundary fraction and grain size on intergranular cracking. The effect of the GBCD on intergranular stress corrosion cracking and intergranular corrosion in a nickel-based alloy 600 (Ni16Cr9Fe) is determined. Important factors in achieving microstructural optimization of alloy 600 are presented. These results provide direct experimental support for the model of intergranular crack propagation, and demonstrate the importance of grain boundary structure control for enhancing the resistance of a material to intergranular degradation.
122 citations
TL;DR: In this paper, the effect of radiation-induced segregation (RIS) on IGSCC was investigated and strong correlations between IASCC and irradiated yield strength were found.
117 citations
15 Sep 1994-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the grain boundary engineering (GME) approach was used to solve the problem of intergranular stress corrosion cracking in Ni-Cr-Fe alloy coatings.
Abstract: Nickel-based alloys used in nuclear steam generator tubing have been found to be susceptible to intergranular stress corrosion cracking while in service. Following a recently developed model, grain boundary engineering concepts may be used to alleviate these concerns. This paper presents a report on the grain refinement approach in the proposed model which results in a higher probability of arresting stress corrosion cracks before reaching a critical length at which failure occurs. For this purpose, an electroplating system was developed to produce ternary Ni-Cr-Fe alloy coatings. Electroplating conditions are given for the production of Alloys 600 and 690 having an average grain size in the range 100-250 nm.
102 citations
TL;DR: In this article, the role of pH in chemically assisted fracture and chemically assisted comminution in frictional deformation is evaluated in a double cantilever beam (DCB) crack propagation data.
Abstract: The roles of chemically assisted crack and fracture propagation and chemically assisted comminution in frictional deformation are evaluated in this study. Double cantilever beam (DCB) crack propagation data are presented which show that the role of pH in chemically assisted fracture, and to a lesser extent the role of ionic concentration are important in stress corrosion cracking. Data on very slow crack growth and the stress corrosion limit are also presented. These data suggest that stress corrosion cracking may play an important role in compound earthquakes and in asperity breakdown in faults. The comminution literature is also reviewed in order to assess the role of chemically assisted comminution in frictional deformation. It appears that chemically assisted comminution may be important at low and high ionic strength because it may reduce the effective viscosity and the shear strength of fault gouge. At intermediate ionic concentration the role of pH, as an agent which enhances crack and fracture propagation, appears to be more important in reducing the coefficient of sliding friction.
78 citations
TL;DR: In this paper, it was shown that retrogression and reaging produces coarsening of grain boundary precipitates and thereby improves resistance to stress corrosion cracking, while it causes pronounced heterogeneous precipitation on dispersoids of E (Al18Cr2Mg3) phase inside the grain of 7075 alloy.
Abstract: Retrogression and reaging produces coarsening of grain boundary precipitates and thereby improves resistance to stress corrosion cracking. At the same time it causes pronounced heterogeneous precipitation on dispersoids of E (Al18Cr2Mg3) phase inside the grain of 7075 alloy. Such heterogeneous precipitation does not occur on the coherent dispersoids of Al3Zr phase in 7050 alloy and its absence leads to higher strength compared with 7075 alloy. Supplementary examination of laboratory alloys 7075-Zr and 7075-Cr differing only in transition metal content supports the above result. This effect is probably the reason why retrogression and reaging (T77 heat treatment) is recommended for alloys containing zirconium but not for those containing chromium.MST/1898
56 citations
TL;DR: In this paper, a study of matrix cracking in a unidirectional ceramic-matrix composite under static loading conditions has been conducted and the evolution of crack density with time has been measured using both flexure and uniaxial tension tests.
Abstract: A study of matrix cracking in a unidirectional ceramic-matrix composite under static loading conditions has been conducted The evolution of crack density with time has been measured using both flexure and uniaxial tension tests Subcritical cracking has been observed at stresses below that required to develop matrix cracks in short-duration, monotonic loading tests Furthermore, a relatively high final crack density has been observed following extended periods (~106 s) under static load A fracture mechanics analysis applicable to subcritical crack growth has been developed and used successfully to model the evolution of matrix cracking with time and applied stress The model incorporates the properties of the matrix, fibers, and interfaces, as well as the residual stress and the initial flaw distribution in the matrix
43 citations
01 Jan 1994
TL;DR: In this paper, the authors present a quantitative analysis of the origin of fracture in flat glass and fractal analysis of flat glass containers with and without fiberglass fiberglass, and they propose a method for the analysis of fracture origins in glass.
Abstract: Identation Fractography (B.R. Lawn, D.B. Marshall). Quantitative Fractographic Analysis of Fracture Origins in Glass (J.J. Mecholsky). Stress Wave Fractography (H. Richter, F. Kerkhof). Fractography of Stress Corrosion Cracking in Glass (T.A. Michalske). Fractography of Optical Fibers (H.C. Chandan et al.). Fractography of Fiberglass (P.K. Gupta). Fracture of Glass Containers (J.B. Kepple, J.S. Wasylyk). Fracture and Fractography of Flat Glass (N. Shinkai). Index.
42 citations
TL;DR: In this article, in situ and ex situ Raman microspectroscopy and electrochemical measurements on rotating disc electrodes have been used to identify surface films formed on iron and its alloys with carbon.
TL;DR: In this paper, an approach for improved design and lifetime evaluation of environmental cracking is presented based on fundamental modeling of the underlying processes operative in crack advance, and its application in energy industries is outlined.
TL;DR: Stress corrosion crack growth by slip-dissolution was considered from the standpoint of electrolyte resistance and/or dissolved metal ion concentration in the crack, using a trapezoidal mo...
Abstract: Stress corrosion crack growth by slip-dissolution was considered from the standpoint of electrolyte resistance and/or dissolved metal ion concentration in the crack, using a trapezoidal mo...
TL;DR: In this paper, a prediction system was established based upon sulfide stress cracking (SSC) as a phenomenon of hydrogen embrittlement, and the content of H entering into steel (HFe) could be predicted from the hydrogen sulfide (H2S) concentration and hydrogen ion (H+) concentration by the equation: HFe (in ppm) = 13 × (H+ × H 2S)0.26
Abstract: It is important to systematically assess the severity of a sour environment for susceptibility to sulfide stress cracking (SSC). A prediction system was established based upon SSC as a phenomenon of hydrogen embrittlement (HE). The content of H entering into steel (HFe) could be predicted from the hydrogen sulfide (H2S) concentration and hydrogen ion (H+) concentration by the equation: HFe (in ppm) = 13 × (H+ × H2S)0.26. SSC failure stress decreased with increases in HFe for any combination of pH and H2S. A critical hydrogen content (Hc) below which no SSC occurred decreased with increases in yield strength (YS) of a steel and could be formulated as a function of YS.
TL;DR: In this article, a study on stress corrosion cracking (SCC) of Ti90-Al6-V4 wire in anhydrous methanol has been conducted, which focused on developing a relationship between microscopic deformation and corrosion current density in the incubation period of the wire.
TL;DR: The effect of molybdenum (Mo) content on the sulfide stress cracking (SSC) resistance of low-carbon (C), low-alloy steels in hydrogen sulfide (H2S)-saturated sodium chloride (NaCl) solutio...
Abstract: The effect of molybdenum (Mo) content on the sulfide stress cracking (SSC) resistance of low-carbon (C), low-alloy steels in hydrogen sulfide (H2S)-saturated sodium chloride (NaCl) solutio...
TL;DR: In this paper, a model system (isothermally sensitized 304 stainless steel in the SL-EPR test environment) was examined in order to assess the significance of the percentage of active grain boundaries on intergranular stress-corrosion cracking (IGSCC) susceptibility.
Abstract: A model system (isothermally sensitized 304 stainless steel in the SL-EPR test environment) was examined in order to assess the significance of the percentage of active grain boundaries on intergranular stress-corrosion cracking (IGSCC) susceptibility. The relationship between the primary passivation potential and Cr concentration was exploited in order (1) to determine the population distributions of grain boundary minimum Cr contents and (2) to subsequently control the quantity of active grain boundaries in a constant extension rate (CER) test. A significant decrease in resistance to IGSCC was observed when greater than 23 pct of the grain boundaries were active during the CER test, regardless of the distribution of Cr-depletion levels among the individual grain boundaries. Such an abrupt decrease in IGSCC resistance at greater than 23 pct active grain boundaries has been interpreted within the context of bond percolation theory. This critical value corresponds to a one-dimensional bond percolation threshold for a three-dimensional array of tetrakaidecahedra and confirms the results of Wells and co-workers. The implications of a possible threshold in the case of IGSCC in sensitized 304 stainless steel (304SS) exposed to oxygenated water at 288 °C are examined. Here it is believed that the 23 pct criterion is a necessary but not sufficient criterion for IGSCC. Other considerations are discussed.
TL;DR: In this article, an aluminum bronze (Copper [Cu]-7% Al) (UNS C61400) was found to be susceptible to stress corrosion cracking (SCC) in 3.4% NaCl under relatively high anodic potentials (≥ 300 mVNHE).
Abstract: α-Aluminum bronze (Copper [Cu]-7% Al) (UNS C61400) was found to be susceptible to stress corrosion cracking (SCC) in 3.4% NaCl under relatively high anodic potentials (≥ 300 mVNHE), i.e., ...
TL;DR: In this paper, a critical examination of the surface mobility mechanism of stress-corrosion cracking of Galvele is presented using arguments based upon the thermodynamics of stressed solids.
11 Jul 1994
TL;DR: In this article, the authors developed corrosion-fatigue curves for austenitic stainless steel (SS) pipes in aqueous environments corresponding to normal BWR water chemistries, for BWRs that add hydrogen to the feedwater, and for pressurized water reactor primary system-coolant chemistry.
Abstract: Fatigue and environmentally assisted cracking of piping, pressure vessel cladding, and core components in light water reactors are potential concerns to the nuclear industry and regulatory agencies The degradation processes include intergranular stress corrosion cracking of austenitic stainless steel (SS) piping in boiling water reactors (BWRs), and propagation of fatigue or stress corrosion cracks (which initiate in sensitized SS cladding) into low-alloy ferritic steels in BWR pressure vessels Crack growth data for wrought and cast austenitic SSs in simulated BWR water, developed at Argonne National Laboratory under US Nuclear Regulatory Commission sponsorship over the past 10 years, have been compiled into a data base along with similar data obtained from the open literature The data were analyzed to develop corrosion-fatigue curves for austenitic SSs in aqueous environments corresponding to normal BWR water chemistries, for BWRs that add hydrogen to the feedwater, and for pressurized water reactor primary-system-coolant chemistry The corrosion-fatigue data and curves in water were compared with the air line in Section XI of the ASME Code
TL;DR: In this paper, the effects of shot peening on the corrosion and stress corrosion cracking (SCC) behaviors of sensitized alloy 600 (UNS N06600) were studied.
Abstract: Effects of shot peening on the corrosion and stress corrosion cracking (SCC) behaviors of sensitized alloy 600 (UNS N06600) were studied. Electrochemical potentiokinetic reactivation (EPR) tests in 0.01 M sulfuric acid (H2SO4) + 0.001 M potassium thiocyanate (KSCN) solution and immersion tests in boiling 25% nitric acid (HNO3) solution were used to evaluate the effect of heat treatment on the degree of sensitization of alloy 600. Potentiodynamic polarization tests in 0.01 M sodium thiosulfate (Na2S2O3) solution at 95°C revealed shot peening increased the anodic current density (CD) of the alloy. However, SCC tests using U-bend specimens indicated shot peening substantially increased the crack initiation time in the same environment. The delayed crack initiation of SCC for shot-peened alloy 600, which is potential dependent, was attributed to the presence of compressive residual stresses and the severely deformed surface microstructure.
TL;DR: In this article, slow strain rate tests were conducted in solutions of HCl + NaCl at ambient temperature on type 304 (UNS S30400) stainless steel weldments that exhibited a duplex ferrite-austenite structure in the weld fusion zone.
Abstract: Slow strain rate tests (SSRT) were conducted in solutions of hydrochloric acid (HCl) + sodium chloride (NaCl) at ambient temperature on type 304 (UNS S30400) stainless steel (SS) weldments that exhibited a duplex ferrite-austenite structure in the weld fusion zone. Results indicated the weld fusion zone corroded preferentially. Stress corrosion cracking (SCC) initiated and propagated along the ferrite-austenite interphase. Austenitic dendrite was observed by scanning electron microscopy (SEM) in the fracture surface morphology. This interfacial cracking was attributed to the formation of a complex cell structure consisting of weld fusion zone/parent metal with delta-ferrite/austenite in the weld zone. The delta-ferrite was microanodic phase. The proposed model of SCC for type 304 SS weldments in HCl + NaCl was film formation-slip (film rupture)-dissolution-crack propagation. Because of the presence of the complex cell structure, the surface film was nonuniform, which was favorable for crack initi...
TL;DR: In this paper, slow strain rate tests of cold-worked X-52 carbon (C) steel showed stress corrosion cracking (SCC) could be induced in dilute aqueous sulfate solutions at 50°C.
Abstract: Slow strain rate tests of cold-worked X-52 carbon (C) steel showed stress corrosion cracking (SCC) could be induced in dilute aqueous sulfate solutions at 50°C. The crack growth rate was of the same order of magnitude reported previously for carbonated solutions. Cracking susceptibility increased for potentials more anodic and more cathodic than the corrosion potential (Ecorr) measured in deaerated solution. Transgranular cracking was observed in pH 6.2 solutions and at Ecorr in pH 8 solutions.
TL;DR: In this paper, Sieradzki and Friedersdorf's work is analyzed and it is made evident that these authors have assumed thermodynamic equilibrium conditions for surfaces undergoing a corrosion process, and that vacancies are being injected into the considered metal surfaces during the corrosion process.
TL;DR: Radiation hardening and radiation-induced chromium depletion were related to intergranular stress corrosion cracking (IGSCC) response among various stainless steels (SS) in this article.
Abstract: Radiation hardening and radiation-induced chromium (Cr) depletion were related to intergranular stress corrosion cracking (IGSCC) response among various stainless steels (SS). Available da...
TL;DR: In this paper, the authors showed that the addition of benzotriazole (BTA) to 0.1 M sodium nitrite solution produces an inhibitive effect on the stress corrosion cracking (SCC) of α-brass under applied anodic potential.
Patent•
25 Feb 1994
TL;DR: In this paper, the authors proposed a method to detect the generating time of stress corrosion cracking by connecting a material to be measured and a counter electrode, a calomel electrode, which is connected to the material with a liquid path, a potentiometer and the like, and monitoring and detecting the change in potential.
Abstract: PURPOSE:To make it possible to detect the generating time of stress corrosion cracking readily and accurately by connecting a material to be measured and a counter electrode, a calomel electrode, which is connected to the material to be measured with a liquid path, a potentiometer and the like, and monitoring and detecting the change in potential. CONSTITUTION:A material to be measured 3 such as carbon steel and a counter electrode 1 such as platinum are inserted into a container 9 containing corrosion solution 2 at a specified interval. A calomel electrode 7 indicating a reference potential is electrically connected to the material to be measured 3 with an agar bridge 8 obtained by mixing and freezing agar and potassium chloride in a glass tube. These three electrodes, a potentiometer 6, ammeter 4, a resistor 10 and an external power supply 5 are electrically connected by using conductor wires and the agar bridge 8, and a circuit is formed. As the solution 2, sea water or the like under the same conditions as the actually using conditions or hydrochloric acid or sulfuric acid of about 5-10% is used. The resistance of the resistor 10 is changed so that the potential becomes constant between the material to be measured 3 and the counter electrode 1, and the value is measured with the potentiometer 6. When cracks and the like occur in the material to be measured because of stress corrosion cracking, the resistance is changed, and the corrosion potential is changed considerably largely. Thus the occurrence of cracks and the like can be detected.
Journal Article•
TL;DR: The most widely specified weldable aluminum alloys are Alloy 6061, 5083, 5052, and 5454 as discussed by the authors, which is a combination of 0.25Cu, 0.6Si, 1.0Mg, and 0.20Cr. Dickerson put the cut-off point in weldability at 3.5% magnesium.
Abstract: The fact that business is good in aluminum welding is a sure sign that more manufacturers and fabricators are using GMA and GTA welding to build new products out of this lightweight nonferrous metal. Among the most widely specified weldable grades are Alloys 6061, 5083, 5052 and 5454. A rundown on these four alloys, including properties and selected applications, is provided. Any company working with aluminum for the first time needs to know something about these four alloys. Alloys of copper-magnesium-silicon combination, of which 6061 is one, are heat-treatable. The three 5XXX series alloys, on the other hand, are nonheat-treatable. According to P.B. Dickerson, consultant, Lower Burrell, Pa., 5083, because of its high magnesium content, is the easiest of the four alloys to arc weld. Dickerson put the cut-off point in weldability at 3.5% magnesium. To prevent cracking, he added, both 6061 and 5052 require much more filler metal than do the other two alloys. Alloy 6061 consists of 0.25Cu, 0.6Si, 1.0Mg, and 0.20Cr. The main applications for 6061 aluminum are structural, architectural, automotive, railway, marine and pipe. It has good formability, weldability, corrosion resistance and strength. Although the 6XXX series alloys are prone to hot cracking, this condition canmore » be readily overcome by correct choice of joint design and electrode. The most popular temper for 6061 is T6, although the -T651, -T4, and -F temper are also popular. The -T651 temper is like a -T6 temper, only it has received some final stretch hardening. The -T4 temper has been solution heat-treated and quenched. The -F temper is in the as-fabricated condition.« less
Patent•
13 Apr 1994
TL;DR: In this paper, a high strength stainless steel for engine gasket for automobile, which contains, by weight, 0.1-0.5% C, 2% Si, 5% Mn, 11-18% Cr, 1.2% N, and 0.0005% H and in which the metallic structure of nonmetallic inclusions is composed of tempered martensite and Vickers hardness is regulated to 400-550.
Abstract: PURPOSE:To produce a high strength stainless steel most suitable for engine gasket for automobile, etc., and excellent in spring characteristic, fatigue characteristic, and stress corrosion cracking resistance. CONSTITUTION:This steel is a stainless steel for engine gasket, which contains, by weight, 0.1-0.5% C, <=2% Si, <=5% Mn, 11-18% Cr, <=0.01% S, <=0.01% O, 0.01-0.2% N, and <=0.0005% H and in which the metallic structure of <=0.01% space factor of nonmetallic inclusions is composed of tempered martensite and Vickers hardness is regulated to 400-550. Further, if necessary, Al, Mg, Ca, Ni, Cu, Mo, Ti, and Nb are incorporated. Moreover, in order to attain this hardness, hardening heat treatment at 900-1050 deg.C and tempering heat treatment at 150-500 deg.C are carried out after cold rolling.