Optical Microscope

3 cases · 29 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Corrosion Standard: API clear all

Optical Microscope — sub-branches

As polished micrography 4Micrography by OM 2Nital Etched Micrography by OM 23

Results

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Micrography presenting a uniform and refined tempered martensitic structure.
39
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 - Uniform Structure
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
The microstructure of the pipe, presented in a longitudinal section, is an uniform tempered martensite.
105
VIEW
ML00068 / Sep.2020
Corrosion Fatigue of a 5" Drill Pipe
M - Low Alloy Medium Carbon QTP - Seamless PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Martensite

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 presenting a uniform and refined tempered martensitic structure.
39
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 - Martensite
Micrographic detail of the tempered martensite.
40
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 - Martensite
Micrography of a longitudinal section of the pipe, at the external pipe surface, where there is a corroded spot. The microstructure is tempered martensite and at the surface the pipe 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 - External Surface
Micrography of a longitudinal section of the pipe, at the external pipe surface, where there is a crack propagating from the corroded spot. The microstructure is tempered martensite and at the surface the pipe is slightly decarburized.
27
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 - Crack
Micrographic detail of the crack from the corroded spot.
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 - Corrosion

+7 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 →

ML00068 — Corrosion Fatigue of a 5" Drill PipeM - Low Alloy Medium Carbon QTP - Seamless PipeAp - O&G Well DrillingCd - Corrosion Fatigue
The micrography in the as polished condition of the longitudinal section of the pipe close to the washout, shows that at the tool mark tip (notch from the external surface) a fatigue crack already started from a corroded region (pitting).
187
VIEW
ML00068 / Sep.2020
Corrosion Fatigue of a 5" Drill Pipe
M - Low Alloy Medium Carbon QTP - Seamless PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Micrography by OMDf - Pitting
Micrographic detail, in the as polished condition, of the corrosion fatigue crack.
90
VIEW
ML00068 / Sep.2020
Corrosion Fatigue of a 5" Drill Pipe
M - Low Alloy Medium Carbon QTP - Seamless PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Micrography by OMDf - Fatigue Crack
The micrography of one of the (multiple) cracks shows the slightly irregular morphology of the cracking, typical of a corrosion-fatigue mechanism.
281
VIEW
ML00068 / Sep.2020
Corrosion Fatigue of a 5" Drill Pipe
M - Low Alloy Medium Carbon QTP - Seamless PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Corrosion Cracking
Micrographic detail of the slightly irregular crack propagation, typical of a corrosion-fatigue mechanism.
76
VIEW
ML00068 / Sep.2020
Corrosion Fatigue of a 5" Drill Pipe
M - Low Alloy Medium Carbon QTP - Seamless PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Corrosion Cracking