Subsea

3 cases · 16 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Product: Welded Joint Standard: UNS Capture method: Scanning Electron Microscope clear all

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Microstructural analysis of the valve body structure, close to the position where the cracking has occurred. The structure is ferritic austenitic, with a large amount of detrimental phases associated to the ferritic structure, probably sigma phase.
92
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Micrography by SEMDf - Sigma
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
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

More from these cases

ML00134 — Brittle Fracture of a Superduplex Valve BodyM - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Micrographic details by scaning electron microscopy. The structure is ferritic austenitic, with a large amount of detrimental phases associated to the ferritic structure, probably sigma phase.
85
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Micrography by SEMDf - Sigma
High magnification details by scaning electron microscopy. The structure is ferritic austenitic, with a large amount of detrimental phases associated to the ferritic structure, probably sigma phase.
81
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Micrography by SEMDf - Sigma
Higher magnification detail of the sigma phase by scaning electron microscopy.
76
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Micrography by SEMDf - Sigma
Fractographic aspect of the valve body fracture surface after opening the crack. The fracture micromechanism is brittle, by cleavage, with several secondary microcracks associated to the sigma phase.
54
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Fractography by SEMDf - Cleavage Facets
Fractographic detail of the valve body fracture surface after opening the crack. The fracture micromechanism is brittle, by cleavage, with several secondary microcracks associated to the sigma phase.
52
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Fractography by SEMDf - Cleavage Facets

+1 more from this case →

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
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