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8 cases · 32 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Application: Offshore Capture method: Scanning Electron Microscope clear all

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Scanning electron microscopy image of the chromium plated cylinder surface, presenting deposits and localized dissolution under deposits. There are different stages of corrosion in this region, observed in low magnification. Small areas of attack and a shallow pitting with deposits that were analyzed by EDS and revealed the presence of S.
903
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Surface Aspect by SEMDf - Localized Corrosion
Microscopic detail of the cracks at the surface of the pin, close to the fracture. It is possible to see that the cracks are not associated to plastic deformation at the surface. Instead they are brittle and associated to regions where the material lost the passivation (dark grey stains at the surface). Some cracks that already opened (a little) showed deformation at the tips.
1024
VIEW
ML00085 / Nov.2017
Corrosion Fatigue of a Martensitic SS Pin
M - Martensitic Stainless SteelP - Forged PinAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Surface Aspect by SEMDf - Multiple cracks
Micrographic detail of the intergranular secondary cracks, parallel to the fracture, typical of a hydrogen assisted cracking. Close to the cracking it is possible to see an elongated inclusion, probably of a sulfide type.
26
VIEW
ML00079 / Jul.2017
Hydrogen Cracking of a Maritime Chain Link
M - High Strength Low AlloyP - Chain LinkAp - OffshoreCd - Hydrogen Embrittlement
Cm - Micrography by SEMDf - Intergranular Cracking
Aspect of a micrographic sample by scanning electron microscopy showing the external pipe surface, in the bottom, the fracture at the left side of the figure and several spots of pitting corrosion from the external surface. The polished section (transverse to the fracture and in a longitudinal section of the pipe) shows the morphology of the pit , 0.2 mm depth. Original magnification 50x.
54
VIEW
ML00012 / Aug.2017
Vibration Induced Fatigue in a 316/316L SS
M - Austenitic Stainless SteelP - Seamless PipeAp - OffshoreCd - Vibration Induced Fatigue
Cm - Micrography by SEMDf - Pitting
Fusion line micrographic detail. The weld metal is in the right and HAZ in the left.
27
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Kalling Etched Micrography by SEMDf - Fusion Line
Micrographic detail of the bainitic structure at the HAZ of the carbon steel plate, by scanning electron microscopy.
40
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Heat Affected Zone
Micrography of the blade, view inside the grain. The intragranular precipitation presents one unique size of precipitation, not yet coalesced, although the blade was in high temperature service for 50.000 hours. Etched by H2SO4 + HNO3 + H3PO4 reagent.
66
VIEW
ML00042 / Apr.2017
Gas Turbine Blade IN 939, Coated
M - NiCrCo AlloyP - CastAp - Gas TurbineCd - Intergranular Cracking
Cm - Micrography by SEMDf - Intragranular Secondary Precipitation
Regions of the pin thread presenting pitting corrosion.
635
VIEW
ML00016 / Apr.2017
SCC in Free Cutting 303SS
M - Austenitic Stainless SteelP - Machined PartAp - OffshoreCd - Stress Corrosion
Cm - Surface Aspect by SEMDf - Localized Corrosion

More from these cases

ML00128 — MIC of a Stored Hydraulic CylinderM - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Scanning electron microscopy image of the chromium plated surface in a position where the cylinder was not damaged, showing the surface finishing.
35
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Surface Aspect by SEMDf - At the Surface
Scanning electron microscopy image of the chromium plated cylinder in a region of localized dissolution under deposit. Inside the shallow pitting the Cr structure with a network of layers is revealed by the etching effect promoted by microbiollogically induced corrosion.
35
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Surface Aspect by SEMDf - Corrosion
Scanning electron microscopy image in detail of the chromium plated cylinder surface in a region of localized dissolution. The surface shows several microcracks promoted by the effects of the microbiollogically induced corrosion. Inside the corroded pit the network of the chromium layer is evidenced by the MIC attack.
48
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Surface Aspect by SEMDf - Corrosion
ML00085 — Corrosion Fatigue of a Martensitic SS PinM - Martensitic Stainless SteelP - Forged PinAp - O&G Well DrillingCd - Corrosion Fatigue
The fractographic analysis of the pin showed fatigue striation at the subcritical propagation region.
75
VIEW
ML00085 / Nov.2017
Corrosion Fatigue of a Martensitic SS Pin
M - Martensitic Stainless SteelP - Forged PinAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Fractography by SEMDf - Fatigue Striation
The fractographic analysis of the pin showed ductile final fracture, by dimples.
76
VIEW
ML00085 / Nov.2017
Corrosion Fatigue of a Martensitic SS Pin
M - Martensitic Stainless SteelP - Forged PinAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Fractography by SEMDf - Dimples
ML00012 — Vibration Induced Fatigue in a 316/316L SSM - Austenitic Stainless SteelP - Seamless PipeAp - OffshoreCd - Vibration Induced Fatigue
Fracture aspect after opening the cracking, in the location where the fatigue cracking was iniciated. There is a pitting corrosion, 0.3 mm depth.
58
VIEW
ML00012 / Aug.2017
Vibration Induced Fatigue in a 316/316L SS
M - Austenitic Stainless SteelP - Seamless PipeAp - OffshoreCd - Vibration Induced Fatigue
Cm - Fractography by SEMDf - Fatigue Crack
Detail of the fatigue fracture iniciation point, at the surface, in a pitting corrosion 0.3 mm depth.
58
VIEW
ML00012 / Aug.2017
Vibration Induced Fatigue in a 316/316L SS
M - Austenitic Stainless SteelP - Seamless PipeAp - OffshoreCd - Vibration Induced Fatigue
Cm - Fractography by SEMDf - Pitting
Fractographic detail of the pitting corrosion in the region of iniciation of the fatigue cracking, at the external surface of the pipe.
52
VIEW
ML00012 / Aug.2017
Vibration Induced Fatigue in a 316/316L SS
M - Austenitic Stainless SteelP - Seamless PipeAp - OffshoreCd - Vibration Induced Fatigue
Cm - Fractography by SEMDf - Pitting
Detail of the fatigue fracture propagation, with striation micromechanism.
48
VIEW
ML00012 / Aug.2017
Vibration Induced Fatigue in a 316/316L SS
M - Austenitic Stainless SteelP - Seamless PipeAp - OffshoreCd - Vibration Induced Fatigue
Cm - Fractography by SEMDf - Fatigue Striation
Fractographic detail of fatigue striation.
41
VIEW
ML00012 / Aug.2017
Vibration Induced Fatigue in a 316/316L SS
M - Austenitic Stainless SteelP - Seamless PipeAp - OffshoreCd - Vibration Induced Fatigue
Cm - Fractography by SEMDf - Fatigue Striation

+2 more from this case →

ML00045 — Subsea Tubular F6NM Martensitic SSM - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Micrographic detail of the base metal tempered martensite.
24
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Kalling Etched Micrography by SEMDf - Base Metal
Micrographic detail of the weld metal tempered martensitic microstructure.
25
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Kalling Etched Micrography by SEMDf - Weld Metal
ML00052 — Cold Cracks in API 5CT L80 Tube Welded to a Structural PartM - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Micrographic detail of the ferritic structure in the weld metal close to the low alloy steel tube, by scanning electron microscopy. The weld metal presents a typical aspect for high strenght weld metal (100% acicular ferrite).
32
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Weld Metal
Micrographic detail of the fusion line of the carbon steel plate, by scanning electron microscopy, showing the bainitic structure at the HAZ and ferritic structure in the weld metal.
34
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Fusion Line
Micrographic detail of the ferritic structure in the weld metal close to the carbon steel plate, by scanning electron microscopy. The weld metal presents a typical aspect for low strenght weld metal (grain boundary and primary ferrite, plus acicular ferrite).
30
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Weld Metal
Micrographic detail of the fusion line of the low alloy steel tube, by scanning electron microscopy, showing the martensitic structure at the HAZ and acicular ferritic structure in the weld metal.
29
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Fusion Line
Micrographic detail of the martensitic structure at the HAZ of the low alloy steel tube, by scanning electron microscopy.
40
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Surface Aspect by SEMDf - Heat Affected Zone

+2 more from this case →

ML00042 — Gas Turbine Blade IN 939, CoatedM - NiCrCo AlloyP - CastAp - Gas TurbineCd - Intergranular Cracking
Micrographic detail of the diffusion coating. H2SO4 + HNO3 + H3PO4 etched.
47
VIEW
ML00042 / Apr.2017
Gas Turbine Blade IN 939, Coated
M - NiCrCo AlloyP - CastAp - Gas TurbineCd - Intergranular Cracking
Cm - Micrography by SEMDf - Coating
ML00016 — SCC in Free Cutting 303SSM - Austenitic Stainless SteelP - Machined PartAp - OffshoreCd - Stress Corrosion
Regions of the localized corrosion spots associated to non metallic inclusions.
123
VIEW
ML00016 / Apr.2017
SCC in Free Cutting 303SS
M - Austenitic Stainless SteelP - Machined PartAp - OffshoreCd - Stress Corrosion
Cm - Surface Aspect by SEMDf - Non Metallic Inclusions
Detail of the pin surface showing that the material easily cracks because it presents regions of localized corrosion.
45
VIEW
ML00016 / Apr.2017
SCC in Free Cutting 303SS
M - Austenitic Stainless SteelP - Machined PartAp - OffshoreCd - Stress Corrosion
Cm - Surface Aspect by SEMDf - Fracture