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3 cases · 53 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Application: Oil and Gas Microstructure: Dendritic clear all

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Image by scanning electron microscopy of the metallurgically bonded interface of the internally cladded pipe. It is a seamless pipe in a low alloy steel X70 cladded by welding overlay of Alloy 625 (by automatic GTAW process). The region is a detail of the interface inside the Ni alloy weld metal, presenting columnar grains and intragranular preciptation. The pipe was heat treated before bending (solution annealing) and after bending (quenching and tempering to meet X70 grade). The microhardness of this region is higher than the value obtained out of this region, in the overlay.
657
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Electrolytic Etch Micrography by SEMDf - Clad Interface
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
Micrography of a transverse section of the lifting part, showing interdendritic voids close to the surface at the inner diameter of the padeye. The microstructure is tempered martensite.
450
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Casting defects

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ML00132 — Seamless Pipe Overlaid with Alloy 625M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
The 4 1/2" nominal diameter seamless pipe internally overlaid with Alloy 625. This pipe corresponds to a 90° curve. The overlaid pipe was heat treated before and after bending. The final quenching and tempering heat treatment was conducted to meet API 5L X70 properties.
113
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Aspect Before AnalysisDf - Welded Joint
The macrography of a longitudinal section shows the low alloy (C-Mn) steel pipe, internally cladded by overlay in two layers.
88
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Electrolytically Etched MacroDf - Longitudinal Section
Micrography of a longitudinal section of the pipe substrate, in low magnification, showing a uniform microstructure,
79
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure obtained by the pipe quenching and tempering,
72
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrographic detail of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure.
68
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Bainite

+12 more from this case →

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

+11 more from this case →

ML00098 — Brittle Fracture of a Casting Lifting DeviceM - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Aspect of the broken padeye. The outer diameter is about 10" and the thickness of the casting is about 2".
22
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - General View
Aspect of the fracture surface, showing a brittle morphology. Flat fracture with chevron marks from regions close to the internal diameter of the padeye, where there are secondary cracks.
22
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Fracture
Micrography of the lifting padeye showing a dendritic path of a quenched and tempered martensitic microstructure. The segregated regions (white interdendritic regions) are more clearly identified in low magnification. Voids are located in these segregated regions.
21
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the lifting padeye showing a quenched and tempered martensitic microstructure. Voids are located in interdendritic segregated regions.
20
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the lifting padeye showing a quenched and tempered martensitic microstructure. Voids are located in interdendritic segregated regions. At this magnification the segregation is not clear.
16
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Martensite

+12 more from this case →