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3 cases · 37 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Brittle Behavior Microstructure: Martensite clear all

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Micrographic detail of the through wall cracking, slightly branched and thin.
656
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Cracking
The as polished micrographic aspect of the corroded surface shows pitting and several microcracks, probably associated to the biological attack and material embrittlement. Replication technique.
924
VIEW
ML00092 / Sep.2017
MIC of a Valve Body
M - Martensitic Stainless SteelP - Valve BodyAp - Oil and GasCd - Brittle Behavior
Cm - As polishedDf - Microcracks
Aspect of the broken disc spring, 1/4" thick, OD 10". The fracture is flat and transverse to the disc.
604
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Brittle Fracture

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ML00093 — MIC of a Drilling ToolM - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
The tool housing ID 1 1/2" presented a longitudinal through wall cracking, in two positions at 180°. The internal side of the housing presented several pits.
66
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Through Wall Cracking
Micrography of a longitudinal section of the housing presenting a uniform tempered martensitic structure. The material presented a thickness about 2.5 mm in the region where the cracking started.
52
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Uniform Structure
Micrography of a longitudinal section of the housing presenting a uniform tempered martensitic structure.
51
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Aspect of the internal side of the housing presenting multiple cracks in longitudinal direction.
49
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Cracking
The microscopic aspect of the internal side of the housing evidences the characteristics of the multiple cracks, not directly related to pitting corrosion.
41
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Cracks

+10 more from this case →

ML00092 — MIC of a Valve BodyM - Martensitic Stainless SteelP - Valve BodyAp - Oil and GasCd - Brittle Behavior
Aspect of the inner side of a valve body, showing regions of localized corrosion and rust, not expected for this stainless steel.
82
VIEW
ML00092 / Sep.2017
MIC of a Valve Body
M - Martensitic Stainless SteelP - Valve BodyAp - Oil and GasCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Corrosion
Evidences of a stagnated fluid in the internal surface of the valve body.
61
VIEW
ML00092 / Sep.2017
MIC of a Valve Body
M - Martensitic Stainless SteelP - Valve BodyAp - Oil and GasCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Internal Surface
Deep localized corrosion spots, rusted. There are indications that the roughness of the surface influences the localized corrosion location.
61
VIEW
ML00092 / Sep.2017
MIC of a Valve Body
M - Martensitic Stainless SteelP - Valve BodyAp - Oil and GasCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Localized Corrosion
The macroscopic aspect of the surface after preparation. Grinding and polishing.
50
VIEW
ML00092 / Sep.2017
MIC of a Valve Body
M - Martensitic Stainless SteelP - Valve BodyAp - Oil and GasCd - Brittle Behavior
Cm - Surface AspectDf - Localized Corrosion
The forged valve presented an uniform tempered martensitic structure, surface hardness 246HB. Replication technique.
42
VIEW
ML00092 / Sep.2017
MIC of a Valve Body
M - Martensitic Stainless SteelP - Valve BodyAp - Oil and GasCd - Brittle Behavior
Cm - Kalling etched, OMDf - Martensite

+3 more from this case →

ML00080 — MIC of Stacking Disc SpringsM - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Macroscopic aspect of the fracture surface, showing a brittle behavior (chevron marks) and a starting point at the bottom of the groove in the right side of the figure.
42
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Fracture Surface AspectDf - Brittle Fracture
Detail of the fracture starting point, in the bottom of the groove, where there is a pit about 0.5 mm depth.
36
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Fracture Surface AspectDf - Brittle Fracture
Microscopic detail of the fracture surface in the position where the fracture is intergranular, probably due to the MIC attack creating an embrittled condition of the material.
31
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture
Microscopic detail of the fracture surface in the position where the fracture is intergranular, probably due to the MIC attack creating an embrittled condition of the material. A surface film is evident in this position suggesting that the fracture remained open and exposed to the environment during a certain time before the failure was detected.
29
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture
Fracture micromechanisms. Intergranular fracture in the top of the figure (close to the groove) and transgranular fracture in the bottom of the figure, where the mechanism changed to transgranular by quasecleavage.
27
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture

+6 more from this case →