Close to the Internal Surface

15 cases · 33 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

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MIC in Aluminum Brass Tubes
2
VIEW
ML00170 / Sep.2020
MIC in Aluminum Brass Tubes
M - Aluminum BrassP - Seamless tubeAp - MaritimeCd - Preferential Dissolution
Cm - FeCl3+HCl+Ethanol Etched MicroDf - Close to the Internal Surface
Micrography of a longitudinal section of the pipe, at the internal pipe surface, where the coating was detached. The strain hardening effect of the blasting is evident. The microstructure is tempered martensite and the surface is slightly decarburized.
28
VIEW
ML00169 / Nov.2020
Drill Pipe Fracture in the Pipe Body
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
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 the damaged region close to the internal surface, presenting spots of localized dissolution/corrosion.
42
VIEW
ML00135 / May.2018
MIC of a Non Magnetic Drilling Tool
M - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Close to the Internal Surface
Micrography of an axial section of the roller bearing, at the internal surface, where the hardness level was about 21 HRc, indicating that in this region the material was not properly quenched and tempered.
75
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrographic detail of a transverse section of the tubing, close to the internal surface. Ferritic-pearlitic structure, refined.
20
VIEW
ML00116 / Jan.2018
CMn Steel Structural Tubing 6 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrographic detail of a transverse section of the tubing, close to the internal surface. Ferritic-pearlitic structure. Very close to the surface the amount of ferrite is higher than in the center and the grain is coarser, due to a decarburization effect probably occurred when the surface was exposed to high temperature during manufacturing.
13
VIEW
ML00115 / Jan.2018
CMn Steel Structural Tubing 5 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrography of a transverse section of the tubing, close to the internal surface. Ferritic-pearlitic structure, refined.
16
VIEW
ML00114 / Jan.2018
CMn Steel Structural Tubing 8 mm thick
M - CMn SteelP - Seamless Round ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface

More from these cases

ML00169 — Drill Pipe Fracture in the Pipe BodyM - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Micrography of a longitudinal section of the pipe, at the internal pipe surface, where the coating was detached. The strain hardening effect of the blasting is evident. The microstructure is tempered martensite and the surface is slightly decarburized.
26
VIEW
ML00169 / Nov.2020
Drill Pipe Fracture in the Pipe Body
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
ML00141 — Brittle Fracture of a Corroded Gray Cast IronM - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
The fracture surface of the casting cylinder presented, at the internal surface, interconnected graphite flakes and a corroded matrix.
73
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Fractography by SEMDf - Close to the Internal 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 corroded surface of the cast cylinder, with 0.5 mm penetrations, showing that the graphites are interconnected and create a notch morphology, critical for a material that presents 1% ductility.
31
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
Micrographic aspect 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.
23
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
Micrographic detail 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 a thick oxide layer at the internal surface, characteristic of 10 years operating with treated water, and the large graphite flakes interconnecting.
23
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

+1 more from this case →

ML00135 — MIC of a Non Magnetic Drilling ToolM - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Micrography of the damaged region close to the internal surface, presenting a deep pitting corrosion morphology.
35
VIEW
ML00135 / May.2018
MIC of a Non Magnetic Drilling Tool
M - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Close to the Internal Surface
ML00131 — Brittle Failure of a Soft Roller BearingM - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Aspect of the roller bearing fracture surface, by scanning electron microscopy, close to the internal surface. In this position the fracture shows ductile micromechanisms (dimples) as well as decohesion of large carbides and (brittle) cleavage facets, typical of overloading this low strenght, and low toughness, ferritic structure (21 HRc). The structure in this region, ferritic with large broken carbides and small rounded carbides, is of a low toughness, as indicated by the fracture.
54
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Fractography by SEMDf - Close to the Internal Surface
Fracture micromechanism at a region close to the internal surface. In this position the fracture shows ductile micromechanisms (dimples) as well as decohesion of large carbides and (brittle) cleavage facets, typical of overloading this low strenght ferritic structure (21 HRc). The structure in this region, ferritic with large broken carbides and small rounded carbides, is of a low toughness, as indicated by the fracture.
44
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Fractography by SEMDf - Close to the Internal Surface