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6 cases · 76 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Standard: 5L Capture method: Optical Microscope clear all

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Micrography of the pipe base metal, in a longitudinal section, presenting a slight banding and a refined structure.
147
VIEW
ML00153 / Jan.2019
X52 in a Tubular Structure
M - CMn SteelP - Seamless PipeAp - StructureCd - Qualified
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of the pipe transverse section presenting a granular microstructure.
147
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Transverse Section
Image by scanning electron microscopy of the metallurgically bonded interface of the internally cladded pipe. It is a longitudinal seam welded pipe, with substrate in low alloy steel X65 and clad plate in Alloy 625 (welded by a solid state process). The region is a detail in the side of the Ni alloy clad plate where a grain refinement has occurred probably due to recrystallization of a strain hardened region during later heat treatment. The microhardness of this region is a lot higher than the value obtained out of this region, in the clad plate.
904
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Oxalic Acid Electrolytic EtchDf - Clad Interface
Micrography of a longitudinal section of the pipe substrate, in low magnification, showing a uniform microstructure,
79
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of the welded joint fusion line presenting the liquation cracking. The weld metal is in the right side (bottom) and the forged connector heat affected zone is in the left side (top).
83
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracking
The micrography of the pipe in the longitudinal section shows an aligned structure.
60
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal

More from these cases

ML00153 — X52 in a Tubular StructureM - CMn SteelP - Seamless PipeAp - StructureCd - Qualified
Micrography of the pipe base metal, in a longitudinal section. The ferritic structure is refined and it is possible to identify a small variation in the ferritic grain size, that is promoting the slight banding effect.
119
VIEW
ML00153 / Jan.2019
X52 in a Tubular Structure
M - CMn SteelP - Seamless PipeAp - StructureCd - Qualified
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrographic detail of the very refined ferritic structure of the base metal, in the longitudinal section, indicating that the material was heat treated, since no banding is not detectable at this magnification.
101
VIEW
ML00153 / Jan.2019
X52 in a Tubular Structure
M - CMn SteelP - Seamless PipeAp - StructureCd - Qualified
Cm - Nital Etched Micrography by OMDf - Grain refined structure
Micrography of the weded joint at the cap pass fusion line. The columnar structure of the weld metal is to the top of the figure; and it is possible to see the coarse grains at the heat affected zone. Both columnar structure and coarse grains are related to the previous austenite grain boundaries. From the fusion line to the base metal (in the bottom of the figure) the grain sizes are refined.
86
VIEW
ML00153 / Jan.2019
X52 in a Tubular Structure
M - CMn SteelP - Seamless PipeAp - StructureCd - Qualified
Cm - Nital Etched Micrography by OMDf - Welded Joint
Micrography presenting the coarse grain heat affected zone of the welded joint, at the cap pass. The microstructure is bainitic.
82
VIEW
ML00153 / Jan.2019
X52 in a Tubular Structure
M - CMn SteelP - Seamless PipeAp - StructureCd - Qualified
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Micrographic detail of the bainitic structure of the coarse grain heat affected zone, close to the fusion line (to the top of the figure).
76
VIEW
ML00153 / Jan.2019
X52 in a Tubular Structure
M - CMn SteelP - Seamless PipeAp - StructureCd - Qualified
Cm - Nital Etched Micrography by OMDf - Bainitic HAZ

+5 more from this case →

ML00140 — Preferential Corrosion of Pipe Seam WeldM - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Micrography of the pipe transverse section presenting a predominatly ferritic-perlitic microstructure.
132
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the predominatly ferritic-perlitic microstructure. Pipe transverse section.
95
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of the pipe in the leakage area, showing the preferential corrosion in the center of the autogenous weld and oxides inside the crevice, that appearas as a cracking but that is only a localized anodic process.
66
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Localized Corrosion
Micrographic detail of the autogenous seam weld. The localized dissolution occurrs exactly at the weld metal that presents a bainitic structure of average hardness about 230HV, compared to the heat affected zone presenting average of 202 HV and the base metal presenting average of 180HV.
57
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Localized Corrosion
Micrographic detail presenting the slighltly decarburized ferritic structure, with inclusions, in the center of the weld, surrounded by a bainitic structure and the preferential corrosion in the weld.
51
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Localized Corrosion

+5 more from this case →

ML00133 — Seam Welded Pipe Cladded with Alloy 625M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Micrography of a longitudinal section of the pipe substrate, in low magnification, showing a uniform microstructure,
51
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure obtained by the pipe quenching and tempering,
48
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrographic detail of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure,
50
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the pipe at the interface with the clad plate, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
55
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrography of a longitudinal section of the pipe at the interface with the clad plate, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
51
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface

+10 more from this case →

ML00132 — Seamless Pipe Overlaid with Alloy 625M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Micrography of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure obtained by the pipe quenching and tempering,
72
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrographic detail of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure.
68
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the pipe at the overlay fusion line, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
67
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrography of a longitudinal section of the pipe at the overlay fusion line, with Nital etch that reveals only the low alloy steel structure, to the left side of the image. Some decarburization of the low alloy steel substrate is evident since the microstructure is slightly different a little far from the interface.
66
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrographic detail of a longitudinal section of the pipe at the interface with the clad plate, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
59
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface

+7 more from this case →

ML00072 — Liquation Cracks in a High Strength JointM - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
The liquation crack is a hot crack in the base metal (at the HAZ) that induces a solidification crack in the weld metal.
66
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrographic detail of the cracks at the fusion line of the welded joint, at the connector side. The cracking presents morphology of melting regions of impurities at grain boundaries of the large grains of the heat affected zone (HAZ).
57
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Fusion Line
The HAZ presents microcracks at previous austenite grain boundaries. These regions melted during welding and generated cracks associated to low melting temperature phases.
48
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Microcracks
The HAZ presents microcracks at previous austenite grain boundaries. These regions melted during welding and generated cracks associated to low melting temperature phases.
43
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Microcracks
Micrography of the AISI 4130 forging, 5/8" thickness, close to the welded region, in the longitudinal section.
42
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal Left Side

+7 more from this case →

ML00053 — SAW Longitudinal Seam of X70 PipeM - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Detail of the microstructure in the center of the plate, in the longitudinal section. The structure is refined and presents different ferritic grain sizes.
49
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Detail of the microstructure in the center of the plate, in the longitudinal section. The ferritic structure is refined and presents different grain sizes. Carbides are presented in different morphologies (perlite, precipitated) and there are probably microphases (aligned in a central segregation line).
55
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrographic detail of the fusion line of the second pass (not reheated). The HAZ is bainitic and the weld metal microstructure is predominantly formed by acicular ferrite.
51
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Fusion Line
Center of the weld in the second pass. Columnar grains of the previous austenite.
45
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Weld Metal
Fusion line of the first pass (reheated in high temperature). The HAZ is bainitic and the weld metal microstructure is predominantly formed by acicular ferrite.
43
VIEW
ML00053 / Mar.2017
SAW Longitudinal Seam of X70 Pipe
M - Microalloyed SteelP - Longitudinal Seam Welded PipeAp - SubseaCd - Welding
Cm - Nital Etched Micrography by OMDf - Fusion Line

+6 more from this case →