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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: 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: 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 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: 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: 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)

Cathodic protection (2)	+ -
Corrosion and anti-corrosives (2)	+ -
Offshore structures (2)	+ -
Adhesives (1)	+ -
Marine steel (1)	+ -

Marine steel--Fatigue (1)	+ -
Metals--Corrosion fatigue (1)	+ -
Reinforced concrete--Deterioration (1)	+ -
Steel, High strength--Fatigue--Testing (1)	+ -
Steel--Fracture (1)	+ -

Florida Atlantic University (6)	+ -
College of Engineering and Computer Science (4)	+ -
Department of Ocean and Mechanical Engineering (4)	+ -
Badve, Ashwin P. (1)	+ -
Chaix, Olivier. (1)	+ -

KRISHNAMURTHY, RAVI M. (1)	+ -
Luo, Jiunn-Shyong (1)	+ -
RAJPATHAK, SHIRISH SHRIDHAR. (1)	+ -
SLOAN, FORREST EUGENE. (1)	+ -

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