Corrosion

2 cases · 41 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Microstructure: Dendritic clear all

Corrosion — sub-branches

Crevice 1Erosion Corrosion 1

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Aspect of a crevice corrosion of the flange, under the bolt head, showing evidences that the cathodic protection system was not connected to the stainless steel instrument.
1434
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Aspect Before AnalysisDf - Localized Corrosion
Region of the leakage close to the welded joint between the pipe and the 90° elbow, in the 1 1/2" nominal diameter piping, SCH 40 (3.7 mm thick). See the schematic drawing in the next figure
966
VIEW
ML00065 / May.2017
Erosion Corrosion of Monel Piping
M - NiCu AlloyP - Seamless PipeAp - Chemical IndustryCd - Erosion Corrosion
Cm - Aspect Before AnalysisDf - Leakage

More from these cases

ML00122 — Crevice Corrosion in a Subsea SystemM - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Flanged case, 640mm long. The photo presents a general view of the instrumentation system, destroyed after only 6 months in subsea service. The system was manufactured using only 316 stainless steel and the case was 20 mm thick.
335
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Aspect Before AnalysisDf - General View
Aspect of the instrument system after disassembling. The internal part of the case, where the electronic device was operating, was wet by seawater and failed to send signals to the surface.
258
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Aspect Before AnalysisDf - General View
Detail of the electronic device after removing the external case. It is corroded because seawater entered in the equipment that was pressurized from the external sea environment.
228
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Aspect Before AnalysisDf - Corrosion
After a longitudinal cut of the case it was possible to see that a localized corrosion has occurred associated to the regions where there were sealed holes, plugged, in a crevice condition, not related to any welded position.
193
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Transverse Section AspectDf - Corrosion
Micrography of the case, observed in the center of the thickness, showing an equiaxial granular austenitic microstructure, free from carbides. The structure is typical of a 316 SS, in a solution annealed condition.
176
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Micrography by OM using A262 Method ADf - Austenite

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ML00065 — Erosion Corrosion of Monel PipingM - NiCu AlloyP - Seamless PipeAp - Chemical IndustryCd - Erosion Corrosion
Schematic drawing presenting the External piping surface
339
VIEW
ML00065 / May.2017
Erosion Corrosion of Monel Piping
M - NiCu AlloyP - Seamless PipeAp - Chemical IndustryCd - Erosion Corrosion
Cm - Identification drawingDf - Leakage
Aspect of the piping cut in the longitudinal direction, presenting the leakage region close to the welded joint between the pipe and the 90° elbow. The original SCH 40 (3.7 mm thickness) presents an actual average thickness of 2 mm all through the piping extension, evidencing a general thinning. See the schematic drawing in the next figure.
364
VIEW
ML00065 / May.2017
Erosion Corrosion of Monel Piping
M - NiCu AlloyP - Seamless PipeAp - Chemical IndustryCd - Erosion Corrosion
Cm - Aspect Before AnalysisDf - Leakage
Schematic drawing presenting the internal piping surface
234
VIEW
ML00065 / May.2017
Erosion Corrosion of Monel Piping
M - NiCu AlloyP - Seamless PipeAp - Chemical IndustryCd - Erosion Corrosion
Cm - Identification drawingDf - Leakage
Detail of the internal piping surface, showing lack of deposits and a shinning surface, suggesting erosive conditions.
226
VIEW
ML00065 / May.2017
Erosion Corrosion of Monel Piping
M - NiCu AlloyP - Seamless PipeAp - Chemical IndustryCd - Erosion Corrosion
Cm - Surface AspectDf - Leakage
Macrography of the pipe to fitting welded joint, in a region where the thickness loss is almost uniform. The pipe is in the left of the figure and the elbow is in the right, with a general thinning (average of 2 mm, considering that the original thickness was 3.7 mm), and a slightly more intense thickness loss at the weld metal near the elbow side.
183
VIEW
ML00065 / May.2017
Erosion Corrosion of Monel Piping
M - NiCu AlloyP - Seamless PipeAp - Chemical IndustryCd - Erosion Corrosion
Cm - Kalling Etched MacroDf - Welded Joint

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