“corrosion”

3 cases · 33 images for “corrosion”

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Preferential Dissolution clear all

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Aspect of a transverse section of the 4" pipe showing the barnacles adhered to the internal pipe surface, and the leakage position (in the top of the figure). It is possible to see that the deposits are attached all throught the internal pipe perimeter but the damage is localized. The damage morphology suggests it is a crack, or a welding defect, but the microstructural analysis indicated that the damage is a galvanic effect at the autogenous seam weld.
1135
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Longitudinal Section AspectDf - Localized Corrosion
Detailed aspect, by a low magnification microscope, of the internal side of the tube, after longitudinal cut. The tube, that is 1.6mm thick, presented several points of localized corrosion leading to leaks.
46
VIEW
ML00170 / Sep.2020
MIC in Aluminum Brass Tubes
M - Aluminum BrassP - Seamless tubeAp - MaritimeCd - Preferential Dissolution
Cm - Surface AspectDf - Localized Corrosion
Aspect of the CuZn platesheet where it is corroded (cooling medium side). The (hot) air cooler uses treated seawater as the cooling medium and the corroded regions are associated to the regions in the heat exchanger of higher temperatures, and the leakage occurred in regions of contact of the platesheet to cooper alloy tubes.
1167
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Aspect Before AnalysisDf - Corrosion

More from these cases

ML00140 — Preferential Corrosion of Pipe Seam WeldM - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Micrography of the pipe transverse section presenting a granular microstructure.
147
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Transverse Section
Micrography of the pipe transverse section presenting a predominatly ferritic-perlitic microstructure.
132
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the predominatly ferritic-perlitic microstructure. Pipe transverse section.
95
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Aspect of the 4" pipe that was in seawater service for 8 years and leaked in a longitudinal line that corresponds to the seam weld. The internal surface presented thick deposits. Although the pipe was cut with a thermal process, the analysis was conducted after mechanical cutting.
100
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Aspect Before AnalysisDf - General View
Detail of the transverse section of the 4" pipe at the longitudinal seam weld evidencing the leakage position. The damage appears as a through wall opening. The pipe thickness is 8 mm and there are no evidences of general corrosion (the SCH 80 corresponds to 8.6 mm) or pitting at the internal surface.
100
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Transverse Section AspectDf - Leakage

+19 more from this case →

ML00170 — MIC in Aluminum Brass TubesM - Aluminum BrassP - Seamless tubeAp - MaritimeCd - Preferential Dissolution
Scanning electron microscopy aspect of the region inside of a pit. The aspect is of a chemical attack, generated by the metabolic by-products of the adhered microorganism. The effect is of a localized dissolution and the granular tube microsctruture is revealed.
40
VIEW
ML00170 / Sep.2020
MIC in Aluminum Brass Tubes
M - Aluminum BrassP - Seamless tubeAp - MaritimeCd - Preferential Dissolution
Cm - Surface Aspect by SEMDf - Corrosion
MIC in Aluminum Brass Tubes
2
VIEW
ML00170 / Sep.2020
MIC in Aluminum Brass Tubes
M - Aluminum BrassP - Seamless tubeAp - MaritimeCd - Preferential Dissolution
Cm - FeCl3+HCl+Ethanol Etched MicroDf - Localized Corrosion
ML00125 — Dezincification of a Cooler TubesheetM - BrassP - PlateAp - ShipCd - Preferential Dissolution
Aspect of the tubesheet after removal of the cooper alloy tubes and water cleaning. The corrosion is more intense in the regions of tube connection.
176
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Surface AspectDf - Corrosion
Transverse section of the tubesheet, after removal of the tubes. The seawater sie is to the top of the figure. It is possible to see regions of localized corrosion close to the tube position and a red layer all through the plate surface.
182
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Transverse Section AspectDf - Corrosion
Macrographic detail of the transverse section of the tubesheet at the cooper alloy tube position, after removal of the 5/8" tube. The red layer at the top of the plate (exposed to the cooling medium - treated seawater) is a region of selective corrosion, dezincification.
169
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Transverse Section AspectDf - Corrosion
Aspect of the surface of the platesheet at a corroded area, showing the selective attack effect.
99
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Surface Aspect by SEMDf - Corrosion