Subsea

3 cases · 16 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Corrosion Capture method: Scanning Electron Microscope clear all

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Nitronic 60 cylinder. Scanning electron microscopy image of a corroded region at the external surface of the cylinder, that is austenitic. The image shows the localized corroded regions in form of pits.
1228
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Surface Aspect by SEMDf - Localized Corrosion
Aspect by scanning electron microscopy of the cracking at the external surface of the fitting.
47
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - External Surface
Microscopic detail of the fracture surface in the position where the fracture is intergranular, probably due to the MIC attack creating an embrittled condition of the material.
31
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture

More from these cases

ML00121 — Pitting Corrosion in a Subsea SystemM - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Nitronic 60 cylinder. Scanning electron microscopy image of a corroded region at the external surface of the cylinder, that is austenitic. The image shows the structure revealed by dissolution of the material (inside the pits) evidencing the strain hardened layer that is presented at the cylinder surface due to the manufacturing process.
106
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Surface Aspect by SEMDf - Localized Corrosion
Nitronic 60 cylinder. Scanning electron microscopy image detail of a corroded region inside a pitting showing the etched structure (strain hardened austenitic structure).
103
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Surface Aspect by SEMDf - Localized Corrosion
Nitronic 60 cylinder. Scanning electron microscopy image of a corroded region in a pit, at the external surface of the cylinder. The corrosion (dissolution) revealed the strain hardened layer at the surface.
96
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Surface Aspect by SEMDf - Localized Corrosion
17-4 PH rod. Surface aspect by scanning electron microscopy showing a region where the passivation layer was destroyed and a pitting was in the begining.
86
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Surface Aspect by SEMDf - Pitting
ML00094 — MIC of a Subsea Hydraulic LineM - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Aspect by scanning electron microscopy of the cracking at the external surface of the fitting. Interesting to observe that the cracks are deformed.
39
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - External Surface
Aspect by scanning electron microscopy of the cracking at the internal surface of the fitting.
36
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Internal Surface
Aspect by scanning electron microscopy of the cracking at the internal surface of the fitting. Interesting to observe multiple cracks with brittle characteristic.
39
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Internal Surface
The internal surface of the fitting presents multiple cracks not associated to pitting.
39
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Internal Surface
The through wall cracking was opened by citting the two sides and the aspect was characterized by SEM. Although there was a film at the fracture surface, probably because the fitting was removed from service some time after it was leaking, the fracture micromechanism is by quasecleavage, typical of a stress corrosion cracking.
56
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - Fractography by SEMDf - Transgranular Fracture
ML00080 — MIC of Stacking Disc SpringsM - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Microscopic detail of the fracture surface in the position where the fracture is intergranular, probably due to the MIC attack creating an embrittled condition of the material. A surface film is evident in this position suggesting that the fracture remained open and exposed to the environment during a certain time before the failure was detected.
29
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture
Fracture micromechanisms. Intergranular fracture in the top of the figure (close to the groove) and transgranular fracture in the bottom of the figure, where the mechanism changed to transgranular by quasecleavage.
27
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture
Microscopic detail of the fracture surface where it is transgranular, by quasecleavage. This aspect is similar to the one expected for this high strenght material without any embrittlement.
27
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Fractography by SEMDf - Transgranular Fracture
Microscopic detail of the fracture surface where it is transgranular, by quasecleavage. This aspect is similar to the one expected for this high strenght material without any embrittlement.
26
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Fractography by SEMDf - Transgranular Fracture