UNS

67 cases · 615 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Damage Capture method: Optical Microscope clear all

UNS — sub-branches

A03560 1A96061 1C12000 1C28000 1C36000 1C60800 1C68700 1F32800 2G10050 1G10080 1G10200 2G10450 1G10550 1G10700 1G10800 1G12110 1G15220 mod 1G15240 1G41300 3G41400 2G43400 1G48200 1G61500 1J23055 1J91540 1K03101 2N02200 1N04400 1N07718 3N08705 1R50400 2R56400 1S15500 1S17400 3S17700 1S21800 2S30300 1S30400 4S30409 1S31600 4S31603 3S32304 1S32750 3S32760 2S42000 3S43100 mod 1

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Micrography of a transverse section of the ring presenting a uniform tempered martensite structure.
43
VIEW
ML00124 / Feb.2018
MIC of a Martensitic Valve Ring
M - Martensitic Stainless SteelP - ForgingAp - EnergyCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Martensite
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 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
Nitronic 60 cylinder. Micrography of the longitudinal section in the center of the thickness, presenting a fully austenitic microstructure, equiaxial grains, and evidences of the manufacturing process by hot forming.
179
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Micrography by OM using A262 Method ADf - Austenite
Micrography as polished of the longitudinal section of the bolt at the fracture position. The fracture (top of the figure) is rough, characteristic of a ductile fracture.
196
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - As polished micrographyDf - Fracture
Micrography, as polished, of the transverse section of the forged pin with the layer applied by a (thermal) spray and fuse process. The layer presented entrapped pores and globular oxides. It was melted after application by thermal spray (in this case using a flame) but the pin was not heat treated after the full application and melting of the layer and the base metal is ferritc-pearlitic.
51
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - As polished micrographyDf - Transverse Section
Micrography of the thermal spray (TS) layer showing the different alloys, gray oxides and black voids. The Ni base TS alloy is of a yellow colour at the interface with the shaft substrate (in the left). The Cr base TS alloy appears white, similar to the shaft substrate. Longitudinal section of the shaft.
42
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - As polished micrographyDf - Coating Layer
Micrography of the longitudinal section of the fitiing, in a free-cutting steel. The microstructure is predominantly ferritic and there is a large amount of sulfide inclusions, aligned perpendicular to the forming direction.
98
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Longitudinal Section

More from these cases

ML00124 — MIC of a Martensitic Valve RingM - Martensitic Stainless SteelP - ForgingAp - EnergyCd - Brittle Behavior
Micrography of a transverse section of the ring, at the pitting position, as polished, showing that there are intergranular cracks and the martensitic structure is corroded (chemical dissolution) inside the pitting.
33
VIEW
ML00124 / Feb.2018
MIC of a Martensitic Valve Ring
M - Martensitic Stainless SteelP - ForgingAp - EnergyCd - Brittle Behavior
Cm - As polished micrographyDf - Corrosion
Micrographic detail of a transverse section of the ring, showing the corroded martensitic structure (chemical dissolution) inside the pitting.
32
VIEW
ML00124 / Feb.2018
MIC of a Martensitic Valve Ring
M - Martensitic Stainless SteelP - ForgingAp - EnergyCd - Brittle Behavior
Cm - As polished micrographyDf - Corrosion
Micrographic detail of a transverse section of the ring, showing the corroded martensitic structure (chemical dissolution) inside the pitting.
33
VIEW
ML00124 / Feb.2018
MIC of a Martensitic Valve Ring
M - Martensitic Stainless SteelP - ForgingAp - EnergyCd - Brittle Behavior
Cm - As polished micrographyDf - Intergranular Cracking
Micrography of a transverse section of the ring at the cracking position. The cracks are intergranular and opened at the position close to the surface.
27
VIEW
ML00124 / Feb.2018
MIC of a Martensitic Valve Ring
M - Martensitic Stainless SteelP - ForgingAp - EnergyCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Martensite
Micrography of a transverse section of the ring at the cracking position. The cracks are intergranular and opened at the position close to the surface. it is possible to identify dissolution of the structure adjacent to the grain boundaries,
25
VIEW
ML00124 / Feb.2018
MIC of a Martensitic Valve Ring
M - Martensitic Stainless SteelP - ForgingAp - EnergyCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Crack

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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
ML00122 — Crevice Corrosion in a Subsea SystemM - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Micrographic detail of the fully austenitic granular structure of the case, in the center of the thickness.
158
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
Microstructure of the welded region of the padeye, at the fusion line. The weld metal is dendritic, austeno ferritic, in the left side of the figure. The heat affected zone is in the center of the figure and shows no changes in relation to the base metal. The padeye base metal is to the right side of the figure.
120
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 - Welded Joint
Micrographic detail of the fusion line of the welded joint of the padeye. The connector where the padeye was installed was welded to the case, but presented no evidences of corrosion.
110
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 - Welded Joint
Micrographic detail of the crevice corrosion in the case wall, showing that the structure is not affected and is fully austenitic with equiaxial grains typical of a solution annealed condition.
85
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 - Localized Corrosion
Micrographic detail of the crevice corrosion in the case wall, showing that the structure is not affected and is fully austenitic with equiaxial grains typical of a solution annealed condition.
72
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 - Localized Corrosion

+2 more from this case →

ML00121 — Pitting Corrosion in a Subsea SystemM - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Nitronic 60 cylinder. Micrography of the longitudinal section in the center of the thickness, presenting a fully austenitic microstructure, with some aligned non metallic inclusions.
157
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Micrography by OM using A262 Method ADf - Austenite
Nitronic 60 cylinder. Micrographic detail of the longitudinal section in the center of the thickness, presenting a fully austenitic microstructure, equiaxial grains, typical of a solution annealed condition.
136
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Micrography by OM using A262 Method ADf - Austenite
Nitronic 60 cylinder. Micrography of the longitudinal section close to the surface, presenting a fully austenitic microstructure, with a shadow close to the external surface that is associated to a small layer of strain hardened structure (deformation twins).
133
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Micrography by OM using A262 Method ADf - Strain Hardened
Nitronic 60 cylinder. Micrography of the longitudinal section close to the surface, presenting a fully austenitic microstructure, with a 0.15mm layer of strain hardened structure (deformation twins).
120
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Micrography by OM using A262 Method ADf - Strain Hardened
Nitronic 60 cylinder. Micrographic detail of the longitudinal section close to the surface, presenting a fully austenitic microstructure, with a layer of strain hardened structure (deformation twins).
113
VIEW
ML00121 / Feb.2018
Pitting Corrosion in a Subsea System
M - Austenitic / MartensiticP - Rod & CylinderAp - SubseaCd - Pitting Corrosion
Cm - Micrography by OM using A262 Method ADf - Strain Hardened

+4 more from this case →

ML00120 — Ductile Rupture of a Carbon Steel Eye BoltM - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Micrography of a longitudinal section of the bolt in the center of the thickness, presenting a ferritic pearlitic structure with elongated grains due to the forming process, without later heat treatment.
173
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the ferritic pearlitic structure, with grains sligthly elongated.
157
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of a longitudinal section of the bolt at the bottom of the thread fillet, presenting a plastically deformed ferritic pearlitic structure in a very small extension from the surface (about 0.1mm). This analysis was conducted in a position far from the failure and the structure was created by the cold forming process to manufacture the thread.
152
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - Nital Etched Micrography by OMDf - Rolled Thread
Micrographic detail of a longitudinal section of the bolt at the bottom of the thread fillet, presenting a plastically deformed ferritic pearlitic structure. This analysis was conducted far from the failure and the structure was created by the cold forming process to manufacture the thread.
147
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - Nital Etched Micrography by OMDf - Strain Hardened
Micrography of a longitudinal section of the bolt at the thread fillet adjacent to the fracture, presenting a ductile cracking from the bottom of the fillet, propagating with a strong plastic deformation. The deformation lines of the cold formed process (thread cold rolling) are also deformed by the cracking propagation.
141
VIEW
ML00120 / Jun.2018
Ductile Rupture of a Carbon Steel Eye Bolt
M - Low Carbon SteelP - FastenerAp - AutomotiveCd - Overload
Cm - Nital Etched Micrography by OMDf - Ductile Crack

+1 more from this case →

ML00110 — Non Conformance in Spray and Fuse PinM - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Micrography, as polished, of the transverse section of the forged pin with the layer applied by a (thermal) spray and fuse process. The layer was melted after thermal spray application and the layer presents a continuous matrix, but there are globular oxides and pores entrapped.
36
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - As polished micrographyDf - Surface Layer
Micrographic detail, as polished, of the transverse section of the forged pin at the interface between the pin and the spray and fuse layer. The interface presents globular oxides and small pores, entrapped.
35
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - As polished micrographyDf - Surface Layer
Low magnification micrography of the interface between the pin and the spray and fuse layer. Close to the surface, under the layer, the pin presents a ferritic perlitic structure, non conform with the high strenght requirement. Transverse section.
37
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - As polished micrographyDf - Low Mag
Micrography of the pin close to the interface with the spray and fuse layer. Transverse section. The fuse was conducted in high temperature and the pin was cooled very slowly, forming a ferritic-perlitic structure even for this high hardenability base metal.
35
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Low magnification micrography of the pin in the center of the 25 mm thickness. Ferritic-pearlitic structure of the material that slowly cooled after spray and fuse application. Transverse section.
25
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - Nital Etched Micrography by OMDf - Base Metal

+5 more from this case →

ML00108 — Thermal Spray Layer in a Pinion ShaftM - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Micrographic detail, as polished in a longitudinal section, of the interface between the shaft substrate and the thermal spray layer. In the left it is the shaft substrate also presenting parts of aligned inclusions (gray). In the center it is the Ni base TS alloy and in the right it is the Cr base TS alloy. There are also black voids and grey oxides.
33
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - As polished micrographyDf - Coating Layer
Micrography of the interface between the shaft surface and the thermal spray layer. The shaft steel presents a quenched and tempered structure. Longitudinal section.
32
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Coating Layer
Micrographic detail of the interface between the shaft surface and the thermal spray layer. The shaft steel presents a quenched and tempered structure. Longitudinal section.
33
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Coating Layer
Micrographic detail of the interface between the shaft surface and the thermal spray layer. The shaft steel presents a quenched and (over) tempered structure. Longitudinal section.
35
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Coating Layer
Shaft microstructure in the longitudinal section, showing aligned segregations typical of the material forming.
31
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Longitudinal Section

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ML00103 — Brittle Fracture of a Free-Cutting ConnectorM - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Micrographic detail of the longitudinal section of the fitiing, in a free-cutting steel. The microstructure is predominantly ferritic, with small perlitic areas and some free cementite at ferritic grain boundaries. There is a large amount of sulfide inclusions, aligned perpendicular to the forming direction.
107
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Non Metallic Inclusions
Micrography of the transerse section of the fitiing, in a free-cutting steel. The microstructure is predominantly ferritic and the inclusions appear as dots.
97
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Transverse Section
Micrographic detail of the transverse section of the fitiing, in a free-cutting steel. The microstructure is predominantly ferritic, some perlitic areas and free cementite at ferritic grain boundaries. There is a large amount of inclusions, that appear as spots.
82
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Predominantly Ferritic
The longitudinal section of the fitting at the thread shows plastic deformation of the fillets, and a crack at the bottom of the thread.
56
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Crack
Micrographic detail of the longitudinal section of the fitting at the thread, showing a crack at the bottom of the thread.
53
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Crack

+4 more from this case →