Optical Microscope

11 cases · 145 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Damage Microstructure: Ferritic pearlitic Standard: ASTM clear all

Optical Microscope — sub-branches

As polished micrography 18Micrography by OM 5Nital Etched Micrography by OM 122

Results

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BASE METAL SURFACE - Ferritic structure, grain refined.
90
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of a transverse section of the seamless pipe, presenting a ferritic-pearlitic structure.
84
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of the plate in a section, showing a ferritic-pearlitic microstructure in the middle of the thickness.
84
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic aspect, as polished, of the cast cylinder section at the fracture position (top of the figure), close to the internal surface (left side). It is possible to see large graphite flakes.
98
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - As polished micrographyDf - Close to the Internal Surface
Micrography of a transverse section of the pipe, external diameter 33.4 mm schedule XXS, in the center of the 9.1 mm thickness. The structure is predominantly ferritic. Small amount of pearlite.
556
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Predominantly Ferritic
Micrography of a transverse section of the pipe, external diameter 26.7 mm, in the center of the 7.85mm thickness. Refined structure but not uniform. Ferrite and pearlite.
512
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
The micrography of the longitudinal section of the tube, close to OD, shows the paralel cracks, filled with oxides, perpendicular to the surface.
1442
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Close to the External Surface
The micrography shows the region underbead, of the tube HAZ, responsible for the hydrogen cracking (fracture in the right side of the photo - black). The hardness of the HAZ is about 600 HV.
55
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracking

More from these cases

ML00177 — Cr-Mo Seam Welded TubeM - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
BASE METAL SURFACE - The micrography (transverse to the tube) presents the ferritic/pearlitic/bainitic structure.
75
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Granular structure
BASE METAL SURFACE - The microstructure of the base metal is ferritic/pearlitic/bainitic.
74
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Grain refined structure
HAZ SURFACE
72
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Last Bead HAZ
HAZ SURFACE
66
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Last Bead HAZ
HAZ SURFACE
55
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Bainitic HAZ

+18 more from this case →

ML00149 — Vibration Induced Fatigue in a Gas PipingM - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Micrography of a transverse section of the seamless pipe, presenting a ferritic-pearlitic structure.
70
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography showing the cracking starting point, in the pipe, exactly at the margin of the weld.
292
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Nital Etched Micrography by OMDf - Margin of the Weld Crack
Micrographic detail of the cracking starting point, in the pipe, exactly at the margin of the weld.
33
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Nital Etched Micrography by OMDf - Fatigue Crack
Micrography of a section tranverse to the pipe and to the weld between the 8"pipe and the 2" fitting weldolet. The crack starts exactly at the margin of the weld and propagates in the pipe longitudinal direction, in a straight line, not related to any metallurgical aspect.
30
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Micrography by OMDf - Cracking
Micrographic detail of the fatigue crack propagation in the pipe longitudinal direction, in a straight line, not related to any metallurgical aspect.
29
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Micrography by OMDf - Fatigue Crack

+2 more from this case →

ML00143 — Impact of a .308 Winchester on A36 PlateM - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Micrography of the plate in a section, showing a ferritic-pearlitic microstructure in the middle of the thickness, in a position where the plate was not affected by the shot.
65
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the plate in a section, showing a ferritic-pearlitic microstructure in the middle of the thickness.
66
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the ferritic-pearlitic microstructure.
53
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the plate section, as polished, close to the surface that suffered the impact. The plate material deformed during the perforation,
31
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - As polished micrographyDf - Transverse Section
Micrographic detail of the plate section, as polished, close to the surface that suffered the impact. The copper alloy melted and created a yellow-orange deposit.
25
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - As polished micrographyDf - Melted film

+22 more from this case →

ML00141 — Brittle Fracture of a Corroded Gray Cast IronM - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Micrographic aspect, as polished, of the cast cylinder section at the fracture position (top of the figure), in the center of the thickness. It is possible to see a mixture of large graphite flakes and rosette grouping flakes.
80
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - As polished micrographyDf - In the Center of the Thickness
Micrographic aspect, as polished, of the cast cylinder section at the fracture position (top of the figure), close to the external surface (left side). It is possible to see smaller graphite flakes, interdendritic .
79
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - As polished micrographyDf - Close to the External Surface
Micrography of the longitudinal section of the cylinder, at the internal diameter (left side of the figure), in contact with the treated cooling water, presenting large graphite flakes in a predominatly perlitic matrix.
50
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrography of the longitudinal section of the cylinder, at the internal diameter, in contact with the treated cooling water, presenting large graphite flakes in a predominatly perlitic matrix. It is important to mention that the flakes are almost interconnecting themelves.
47
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Graphite in Flakes
Micrography of the longitudinal section of the cylinder, at the internal diameter, in contact with the treated cooling water, presenting large graphite flakes in a predominatly perlitic matrix. It is important to mention that the flakes are almost interconnecting themelves.
48
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Predominantly Pearlitic

+19 more from this case →

ML00112 — 1" XXS Pipe Not Qualified For Low TempM - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Micrography of a transverse section of the pipe, close to the external surface (OD). The pipe presented a predominatly ferritic structure.
43
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Micrography of a transverse section of the pipe, close to the external surface (OD). The pipe presented a 0.2 mm decarburized layer, fully ferritic.
35
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Micrography of a transverse section of the pipe, close to the external surface (OD). The pipe presented a predominatly ferritic structure.
31
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Predominantly Ferritic
Micrography of a transverse section of the pipe, close to the internal surface (ID). The pipe presented a predominatly ferritic structure.
29
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrography of a transverse section of the pipe, close to the internal surface (ID). The pipe presented a predominatly ferritic structure.
22
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface

+2 more from this case →

ML00111 — 3/4" XXS Pipe Not Qualified for Low TempM - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Micrography of a transverse section of the pipe, close to the internal surface (ID). Refined structure. Ferrite and pearlite.
64
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrography of a transverse section of the pipe, close to the internal surface (ID). Refined structure, but not uniform. Ferrite and pearlite. The pearlite colonies appear in a network.
45
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrography of a transverse section of the pipe, close to the internal surface (ID). Refined structure. Ferrite and pearlite. The structure is not uniform. There is a large variation in the ferritic grain size and the pearlite colonies appear forming a network.
39
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of a transverse section of the pipe, close to the external surface (OD). Refined structure. Ferrite and pearlite.
33
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Micrography of a transverse section of the pipe, close to the external surface (OD). Refined structure. Ferrite and pearlite.
35
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the External Surface

+2 more from this case →

ML00104 — Thermal Fatigue of a Boiler TubeM - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
The micrography of the longitudinal section of the tube, close to ID, shows the paralel cracks, filled with oxides, perpendicular to the surface.
229
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Close to the Internal Surface
Micrographic details of the longitudinal section of the tube, close to OD, showing paralel cracks, filled with oxides, perpendicular to the surface.
115
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Cracks Transverse to the Surface
Micrographic details of the longitudinal section of the tube, close to OD, showing paralel cracks, filled with oxides, perpendicular to the surface.
109
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Thermal Fatigue Cracks
Micrographic details of the longitudinal section of the tube, close to ID, showing paralel cracks, filled with oxides, perpendicular to the surface.
103
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Cracks Transverse to the Surface
Micrographic details of the longitudinal section of the tube, close to ID, showing paralel cracks, filled with oxides, perpendicular to the surface.
99
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Thermal Fatigue Cracks

+10 more from this case →

ML00052 — Cold Cracks in API 5CT L80 Tube Welded to a Structural PartM - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Low carbon plate base metal presenting the ferritic perlitic structure.
55
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal
High Strenght Low Alloy steel tube, base metal, presenting the bainitic structure.
54
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of the low carbon steel plate at the fusion line, presenting a bainitic structure at the HAZ and ferritic structure in the weld metal.
82
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Fusion Line
The micrography shows the martensitic region of the tube HAZ responsible for the hydrogen cracking, presenting too high hardness level (600 HV). It is a fresh martensite since the joint was welded in one pass and there was no PWHT.
45
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the weld metal in the center of the fillet showing a 100% acicular ferrite that is a microestructure of a high strenght steel, evidenced the effect of the dilution of the tube chemistry in the weld metal.
40
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal

+1 more from this case →