Subsea

4 cases · 43 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Capture method: NaOH Electrolytic Etched Micro 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.
106
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Sigma
Micrography of a transverse section of the forged bar in the center of the thickness. Ferrite and austenite. Coarse structure.
74
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - NaOH Electrolytic Etched MicroDf - Transverse Section
Micrography of the tubing fusion line. The welding was conducted in two passes. The average hardness at the heat affected zone of the tubing is 257 HV5.
825
VIEW
ML00100 / Nov.2017
Superduplex Tubing to Forging Welded Joint
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Welding
Cm - NaOH Electrolytic Etched MicroDf - Fusion Line Left Side
Micrography of the fitting longitudinal section, showing a coarse austenitic ferritic structure.
39
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - NaOH Electrolytic Etched MicroDf - Duplex structure

More from these cases

ML00134 — Brittle Fracture of a Superduplex Valve BodyM - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Micrographic detail 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.
102
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Sigma
Metallographic detail of the large amount of sigma phase, associated to the ferritic structure.
105
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Sigma
Microstructural analysis of the valve body structure, far from the position where the cracking has occurred, in the bottom of the body. The structure is ferritic austenitic, with some sigma phase, not in a large amount, indicating the valve structure was not uniform.
67
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Ferrite and Austenite
Micrographic detail of the valve body structure, far from the position where the cracking has occurred, in the bottom of the body. The structure is ferritic austenitic, with some sigma phase, not in a large amount, indicating the valve structure was not uniform.
63
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Ferrite and Austenite
Micrographic detail of the valve body structure, far from the position where the cracking has occurred, in the bottom of the body. The structure is ferritic austenitic, with some sigma phase, not in a large amount, indicating the valve structure was not uniform.
61
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Ferrite and Austenite

+8 more from this case →

ML00123 — Non Qualified Superduplex for SubseaM - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Micrography of a longitudinal section of the forged bar in the center of the thickness. Ferrite and austenite. Coarse structure.
61
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - NaOH Electrolytic Etched MicroDf - Longitudinal Section
Micrography of a transverse section of the forged bar in the center of the thickness. Ferrite and austenite. The ferrite amount, measured by metallographic method, manual counting, is 59%.
53
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - NaOH Electrolytic Etched MicroDf - Transverse Section
Micrography of a longitudinal section of the forged bar in the center of the thickness. Ferrite and austenite. The average austenite spacing is 80 microns, a lot larger than the maximum allowed in the specification, of 30 microns. No detrimental phases were identified at the ferrite/austenite interfaces, but the ferrite phase presented a rough aspect. Higher magnification analysis would be required to identify precipitation.
53
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - NaOH Electrolytic Etched MicroDf - Longitudinal Section
Micrographic detail of the ferrite and austenite structure in the transverse section of the forged bar, in the center of the thickness.
53
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - NaOH Electrolytic Etched MicroDf - Ferrite and Austenite
Micrographic detail of the ferrite and austenite structure in the longitudinal section of the forged bar, in the center of the thickness.
55
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - NaOH Electrolytic Etched MicroDf - Ferrite and Austenite
ML00100 — Superduplex Tubing to Forging Welded JointM - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Welding
Micrography of the tubing heat affected zone.
69
VIEW
ML00100 / Nov.2017
Superduplex Tubing to Forging Welded Joint
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Welding
Cm - NaOH Electrolytic Etched MicroDf - HAZ Left Side
Micrography of the tubing heat affected zone.
68
VIEW
ML00100 / Nov.2017
Superduplex Tubing to Forging Welded Joint
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Welding
Cm - NaOH Electrolytic Etched MicroDf - HAZ Left Side
Low magnification micrography of the superduplex stainless steel tubing (base metal), in the longitudinal direction. Refined ferritic-austenitic structure. The average hardness in the section is 264HV5.
58
VIEW
ML00100 / Nov.2017
Superduplex Tubing to Forging Welded Joint
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Welding
Cm - NaOH Electrolytic Etched MicroDf - Base Metal Left Side
Micrography of the superduplex stainless steel tubing (base metal), in the longitudinal direction. Refined ferritic-austenitic structure.
55
VIEW
ML00100 / Nov.2017
Superduplex Tubing to Forging Welded Joint
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Welding
Cm - NaOH Electrolytic Etched MicroDf - Duplex structure
Micrographic detail of the superduplex stainless steel tubing (base metal), in the longitudinal direction. Refined ferritic-austenitic structure.
53
VIEW
ML00100 / Nov.2017
Superduplex Tubing to Forging Welded Joint
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Welding
Cm - NaOH Electrolytic Etched MicroDf - Duplex structure

+10 more from this case →

ML00094 — MIC of a Subsea Hydraulic LineM - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Micrographic detail of the fitting longitudinal section showing a coarse austenitic ferritic structure.
37
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - NaOH Electrolytic Etched MicroDf - Coarse Structure
Micrography of the tubing longitudinal section, showing a refined austenitic ferritic structure.
36
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - NaOH Electrolytic Etched MicroDf - Duplex structure
Micrographic detail of the tubing longitudinal section showing a refined austenitic ferritic structure.
43
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - NaOH Electrolytic Etched MicroDf - Grain refined structure
Micrography of a transverse section of the fitting, at the cracking position. Note the through wall cracking at the coarse austenitic ferritic structure.
43
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - NaOH Electrolytic Etched MicroDf - Transverse Section
Micrographic detail of the region where the cracking was initiated at the internal side of the fitting.
41
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - NaOH Electrolytic Etched MicroDf - Through Wall Cracking

+1 more from this case →