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Title: CHARACTERIZATION OF THE EMBRITTLEMENT TENDENCY OF A CATHODICALLY POLARIZED SUPERFERRITIC STAINLESS STEEL IN SEAWATER (HYDROGEN DAMAGE, INTERGRANULAR).
Creator: KRISHNAMURTHY, RAVI M., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In order to investigate the cracking tendency of cathodically polarized SEACURE superferritic stainless steel, a series of potentiostatically controlled tests were conducted in flowing natural seawater. U-bend and tensile specimens were used to determine the threshold potential and limiting fracture stress. The microstructure was examined using a metallurgical microscope and a chemical analysis was conducted across the grain boundary. These results were then correlated to hydrogen assisted...
Show moreIn order to investigate the cracking tendency of cathodically polarized SEACURE superferritic stainless steel, a series of potentiostatically controlled tests were conducted in flowing natural seawater. U-bend and tensile specimens were used to determine the threshold potential and limiting fracture stress. The microstructure was examined using a metallurgical microscope and a chemical analysis was conducted across the grain boundary. These results were then correlated to hydrogen assisted cracking, by performing SEM and EDAX analyses on fractured U-bend and tensile samples. Finally a model was developed which explained the predominantly intergranular cracking in the static stress condition and also accommodated the transgranular failure during dynamic loading.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14325
Subject Headings: Steel--Fracture, Sea-water corrosion
Format: Document (PDF)

Title: Effect of strain rate and temperature on the stress corrosion cracking tendency of engineering alloys in acidified seawater.
Creator: Kundalgurki, Srivatsa G., Florida Atlantic University, Lipka, Stephen M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The stress corrosion cracking (SCC) tendencies of several engineering alloys were studied in an acidified seawater environment as a function of applied strain rate and electrolyte temperature. The selected alloys included austenitic stainless steels 304L, 316L, 904L and A-286 (an iron-based superalloy at two heat treatments yielding ultimate tensile strengths of 130 and 200 ksi), Inconel 718 (220 ksi ultimate tensile strength) and Hastelloys C-22 and C-276. The slow strain rate test technique...
Show moreThe stress corrosion cracking (SCC) tendencies of several engineering alloys were studied in an acidified seawater environment as a function of applied strain rate and electrolyte temperature. The selected alloys included austenitic stainless steels 304L, 316L, 904L and A-286 (an iron-based superalloy at two heat treatments yielding ultimate tensile strengths of 130 and 200 ksi), Inconel 718 (220 ksi ultimate tensile strength) and Hastelloys C-22 and C-276. The slow strain rate test technique was used to evaluate the SCC strain rate dependency of each alloy at extension rates of 4.7 x 10^-6, 4.7 x 10^-4 and 4.7 x 10^-3 mm/sec. The effect of electrolyte temperature was evaluated at 38C and 60C at a single extension rate of 4.7 x 10^-5 mm/sec. Control specimens were tested in a laboratory air environment at an extension rate of 4.7 x 10^-5 mm/sec. Various mechanical parameters of the specimens tested in the corrosive medium were compared with those of control specimens to quantify the degree of cracking. Fractographic evidence of SCC was obtained using scanning electron microscopy (SEM). An attempt was made to correlate SCC tendency with the alloy's passivation kinetics and microstructure. Atmospheric exposure testing was performed in a simulated space shuttle launch pad environment for selected alloys.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/14853
Subject Headings: Alloys--Stress corrosion, Stress corrosion, Sea-water corrosion
Format: Document (PDF)

Title: STUDY OF ELECTROCHEMISTRY MODIFICATIONS WITHIN CATHODICALLY PROTECTED FATIGUE CREVICES IN 3% SODIUM-CHLORIDE - DISTILLED WATER SOLUTION AND SEAWATER.
Creator: RAJPATHAK, SHIRISH SHRIDHAR., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: It is well recognized that the electrochemistry modifications within cathodically protected fatigue crevices in seawater has pronounced effect on crack growth rate. This study focuses its attention on potential distribution within simulated fatigue crevice as a function of electrolyte velocity, fatigue frequency and cathodic protection potential. Results of salt water electrolyte and seawater electrolyte are compared to bring about the effect of calcareous deposits, Finally, a mathematical...
Show moreIt is well recognized that the electrochemistry modifications within cathodically protected fatigue crevices in seawater has pronounced effect on crack growth rate. This study focuses its attention on potential distribution within simulated fatigue crevice as a function of electrolyte velocity, fatigue frequency and cathodic protection potential. Results of salt water electrolyte and seawater electrolyte are compared to bring about the effect of calcareous deposits, Finally, a mathematical model based on mass transfer laws is developed to rationalise potential distribution trends within fatigue crevice and are compared with the observed behaviour.
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Date Issued: 1983
PURL: http://purl.flvc.org/fcla/dt/14151
Subject Headings: Cathodic protection, Metals--Corrosion fatigue, Sea-water corrosion
Format: Document (PDF)

Title: AN ASPECT OF THE LIMITING CURRENT DENSITY ALONG THE CIRCUMFERENCE OF A STEEL CYLINDER BY THE EFFECT OF THE FLOW VELOCITY (CATHODIC PROTECTION, CIRCULAR, BOUNDARY LAYER THICKNESS).
Creator: WANG, TIEN-JEN., Florida Atlantic University, Smith, Samuel W., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The influence of hydrodynamic parameters and limiting current density by cathodic protection on a steel cylinder in flowing water is investigated. The limiting current density variations along the circumference of a circular cylinder are determined for different flow velocities. Several methods are also used to relate the cathodic current density distribution to variations in hydrodynamic and diffusional boundary layer thickness along the circumference of the cylinder for laminar and...
Show moreThe influence of hydrodynamic parameters and limiting current density by cathodic protection on a steel cylinder in flowing water is investigated. The limiting current density variations along the circumference of a circular cylinder are determined for different flow velocities. Several methods are also used to relate the cathodic current density distribution to variations in hydrodynamic and diffusional boundary layer thickness along the circumference of the cylinder for laminar and turbulent flow regimes. a comparison of experimental current densities on a cylinder to that predicated by theory is also examined.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14316
Subject Headings: Steel--Cathodic protection, Sea-water corrosion
Format: Document (PDF)

Title: Adhesion of calcareous deposits formed on steel surfaces under cathodic polarization.
Creator: Luo, Jiunn-Shyong, Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A procedure has been devised to characterize the adhesion of calcareous deposits formed upon steel in association with cathodic polarization in seawater. This involved bending the substrate in-situ and characterization of deposit debonding in terms of visual appearance, changes in the cathodic current density and the net charge transferred in association with film disruption. Specific attention has been focused upon the influence of exposure time, applied potential, flow rate, temperature,...
Show moreA procedure has been devised to characterize the adhesion of calcareous deposits formed upon steel in association with cathodic polarization in seawater. This involved bending the substrate in-situ and characterization of deposit debonding in terms of visual appearance, changes in the cathodic current density and the net charge transferred in association with film disruption. Specific attention has been focused upon the influence of exposure time, applied potential, flow rate, temperature, substrate surface finish and electrolyte type upon deposit adhesion. Presence of a Mg-rich, inner film as well as the impingement of CaCO3 particles enhanced the adhesion of calcareous deposits. Electrostatic forces, Van der Waals attraction, and chemical alteration of precipitates could be important factors contributing to deposit adhesion.
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Date Issued: 1991
PURL: http://purl.flvc.org/fcla/dt/12271
Subject Headings: Sea-water corrosion, Marine steel, Cathodic protection, Adhesives
Format: Document (PDF)

Title: Calcareous deposits in simulated fatigue cracks of cathodically protected steel in seawater.
Creator: Davidson, Keith Dewayne., Florida Atlantic University, Haratt, William H.
Abstract/Description: An experiment was designed to provide a simulated steel fatigue crack under cathodic protection in seawater for study. Calcareous deposits were found to form in the simulated crack at -0.800, -0.900, -1.000 and -1.100 volts (SCE) with cycle frequencies of both 0.5 and 1.0 Hertz. By X-ray and SEM analysis, calcium carbonate deposits were shown to grow in quantities sufficient to block and become compressed by this simulated crack. Increased fluid velocities from crack pumping were shown to...
Show moreAn experiment was designed to provide a simulated steel fatigue crack under cathodic protection in seawater for study. Calcareous deposits were found to form in the simulated crack at -0.800, -0.900, -1.000 and -1.100 volts (SCE) with cycle frequencies of both 0.5 and 1.0 Hertz. By X-ray and SEM analysis, calcium carbonate deposits were shown to grow in quantities sufficient to block and become compressed by this simulated crack. Increased fluid velocities from crack pumping were shown to negatively affect crystal nucleation and growth. Due to kinetic barriers to crystal growth, aragonite and brucite were determined to be the most likely deposit type; excluding calcite, dolomite and magnesite. The deposits formed at -1.000V were shown by current requirements and SEM to provide the best protection as a coating.
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Date Issued: 1988
PURL: http://purl.flvc.org/fcla/dt/14442
Subject Headings: Steel--Fatigue, Cathodic protection, Sea-water corrosion
Format: Document (PDF)

Title: CORROSION FATIGUE CRACK INITIATION BEHAVIOR OF SEVERAL HIGH STRENGTH STEELS IN SEAWATER (POTENTIAL, CATHODIC, POLARIZATION).
Creator: SLOAN, FORREST EUGENE., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: 'J 'ht' c· f feet of seawater ,_tnd potential on the fatigue crack initiation hehavior of several microalloyed and thermomPrhanically processed steels has been investigated. Five steels with yield strength in t~e range 500 to 750 MPa (73 to 108 ksi) were selected which included a range of processing histories from conventional quenching and tempering to precipitation hardening and direct quenching. These steels were chosen because of their potential utility as materials of construction for...
Show more'J 'ht' c· f feet of seawater ,_tnd potential on the fatigue crack initiation hehavior of several microalloyed and thermomPrhanically processed steels has been investigated. Five steels with yield strength in t~e range 500 to 750 MPa (73 to 108 ksi) were selected which included a range of processing histories from conventional quenching and tempering to precipitation hardening and direct quenching. These steels were chosen because of their potential utility as materials of construction for deep water compliant platform hull and riser systems. Blunt notch compact tension specimens were exposed to natural flowing seawater under constant load ampli tnrlc. conditions at both freely corroding and cathodically protected potentials. Cycles to crack initiation were characterized by cyclic stress intensity range normalized relative to the square root of notch radius. Test data are presented and compared with data from other tests and steels using appropriate stress analysis methods.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14285
Subject Headings: Steel, High strength--Fatigue--Testing, Sea-water corrosion
Format: Document (PDF)

Title: Cathodic polarization response of simulated prestressed concrete piles exposed to natural sea water.
Creator: Chaix, Olivier., Florida Atlantic University, Hartt, William H.
Abstract/Description: Experiments were conducted to determine the effectiveness of localized cathodic polarization for reducing corrosion of simulated prestressed concrete piles containing admixed calcium chloride and exposed to a simulated sea water tidal cycle. The specimens contained both continuous and segmented steel tendons, the purpose of the latter being to facilitate measurement of cathodic protection current. Conductive rubber in an impressed current system was used as the anode material. The specimens...
Show moreExperiments were conducted to determine the effectiveness of localized cathodic polarization for reducing corrosion of simulated prestressed concrete piles containing admixed calcium chloride and exposed to a simulated sea water tidal cycle. The specimens contained both continuous and segmented steel tendons, the purpose of the latter being to facilitate measurement of cathodic protection current. Conductive rubber in an impressed current system was used as the anode material. The specimens were initially freely corroded and then cathodically polarized at a constant current ranging from 0.5 to 1 mA/m$\sp2$ which corresponded to potentials (current-on) which ranged from $-$0.500 to $-$1.100 V(sce) in the anode region. The magnitude of impressed current and its distribution along the embedded steel was monitored as a function of exposure time, level of polarization and water levels. Current-on and instant-off potential distribution for both the continuous and segmented tendons were also measured. The level of cathodic polarization was assessed as a function of position along the specimens by the depolarization method. The results were evaluated within the context of marine bridge substructure cathodic protection technology.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/14865
Subject Headings: Corrosion and anti-corrosives, Sea-water corrosion, Offshore structures, Reinforced concrete--Deterioration
Format: Document (PDF)

Title: Effect of cathodic protection and cyclic frequency on corrosion fatigue of selected high strength steels in seawater.
Creator: Badve, Ashwin P., Florida Atlantic University, Hartt, William H.
Abstract/Description: Study of selected candidate steels for offshore application was undertaken to observe the effects of cathodic protection and cyclic frequency on corrosion fatigue life. Keyhole Compact Tension Fatigue experiments under constant amplitude sinusoidal loading and stress ratio of 0.5 were performed on 25.4 mm thick specimens in natural sea water and also in air upon three different steels (Y.S. 500-563 MPa). These steels represented different strengthening techniques, namely precipitation...
Show moreStudy of selected candidate steels for offshore application was undertaken to observe the effects of cathodic protection and cyclic frequency on corrosion fatigue life. Keyhole Compact Tension Fatigue experiments under constant amplitude sinusoidal loading and stress ratio of 0.5 were performed on 25.4 mm thick specimens in natural sea water and also in air upon three different steels (Y.S. 500-563 MPa). These steels represented different strengthening techniques, namely precipitation hardening, direct quenching--a thermomechanical control process (TMCP), and controlled rolling. Cathodic polarization was in the range between freely corroding and -1.10 Volts (SCE). The tests were performed at a frequency of 0.3 and 1.0 Hz. The results are presented in the S-N and potential versus cycles to initiation format. No effect of frequency (1.0-0.3 Hz) was observed at cathodic protection of -1.10 V (SCE). The steels showed an increase in fatigue life to an optimum potential, and excessive potentials were detrimental. The fatigue life in dry air was greater than in laboratory air (~50% RH).
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14494
Subject Headings: Marine steel--Fatigue, Offshore structures, Sea-water corrosion, Corrosion and anti-corrosives
Format: Document (PDF)

Title: Computer simulation of corrosion fatigue of reinforced concrete beams in marine environment.
Creator: Ranade, Sonali S., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The effect of corrosion on the fatigue life of reinforced concrete beams is studied. Two analytical models are developed to study the chloride diffusion in concrete and the percent reduction in fatigue lives in seawater as compared to air. An initial stress equivalent to the tensile strength of concrete is induced in the rebar to simulate the corrosive nature of marine environment. The analytical values are compared with the available experimental data.
Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/14914
Subject Headings: Concrete beams--Fatigue--Computer simulation, Reinforced concrete--Corrosion, Sea water corrosion
Format: Document (PDF)

Title: COMPUTER MODELING OF POLARIZATION OF A STEEL PLATE AS A FUNCTION OF TEMPERATURE USING FINITE ELEMENT METHOD.
Creator: VARGHESE, BABU., Florida Atlantic University, Smith, Samuel W., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Computerized modeling techniques have been developed for the analysis of polarization behavior, using the expected chemical reactions and transport phenomena applicable to the formation of calcareous deposits. The method uses the ADINAT finite element heat transfer program and is modeled, as much as possible, on theory rather than laboratory measurements. In contrast, the presently available cathodic protection computer models base their polarization behavior on empirical data. The thesis...
Show moreComputerized modeling techniques have been developed for the analysis of polarization behavior, using the expected chemical reactions and transport phenomena applicable to the formation of calcareous deposits. The method uses the ADINAT finite element heat transfer program and is modeled, as much as possible, on theory rather than laboratory measurements. In contrast, the presently available cathodic protection computer models base their polarization behavior on empirical data. The thesis presents experimental versus theoretical data for a simple flat plate configuration under cathodic protection in natural sea water over a range in temperatures. The flat plate allows for a simplified experimental apparatus and simplifies the derivation of equations for the transport phenomena. The program can, however, handle complex three dimensional geometries. Effects of temperature and flow on the formation and protection of calcareous deposits are also discussed in light of the experimental results.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14314
Subject Headings: Plates, Iron and steel--Cathodic protection, Sea-water corrosion
Format: Document (PDF)

Sea-water corrosion (10)	+ -
Cathodic protection (3)	+ -
Corrosion and anti-corrosives (2)	+ -
Offshore structures (2)	+ -
Adhesives (1)	+ -

Alloys--Stress corrosion (1)	+ -
Concrete beams--Fatigue--Computer simulation (1)	+ -
Marine steel (1)	+ -
Marine steel--Fatigue (1)	+ -
Metals--Corrosion fatigue (1)	+ -
Plates, Iron and steel--Cathodic protection (1)	+ -
Reinforced concrete--Corrosion (1)	+ -
Reinforced concrete--Deterioration (1)	+ -
Sea water corrosion (1)	+ -
Steel, High strength--Fatigue--Testing (1)	+ -
Steel--Cathodic protection (1)	+ -
Steel--Fatigue (1)	+ -
Steel--Fracture (1)	+ -
Stress corrosion (1)	+ -

Florida Atlantic University (11)	+ -
College of Engineering and Computer Science (8)	+ -
Department of Ocean and Mechanical Engineering (8)	+ -
Hartt, William H. (6)	+ -
Smith, Samuel W. (2)	+ -

Badve, Ashwin P. (1)	+ -
Chaix, Olivier. (1)	+ -
Davidson, Keith Dewayne. (1)	+ -
Haratt, William H. (1)	+ -
KRISHNAMURTHY, RAVI M. (1)	+ -
Kundalgurki, Srivatsa G. (1)	+ -
Lipka, Stephen M. (1)	+ -
Luo, Jiunn-Shyong (1)	+ -
RAJPATHAK, SHIRISH SHRIDHAR. (1)	+ -
Ranade, Sonali S. (1)	+ -
Reddy, Dronnadula V. (1)	+ -
SLOAN, FORREST EUGENE. (1)	+ -
VARGHESE, BABU. (1)	+ -
WANG, TIEN-JEN. (1)	+ -

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