Corrosion

18 cases · 56 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

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The threads of the carbon steel valve body is corroded. The offshore ambient is wet and chloride rich, creating an aggressive environment for the carbon steel threads.
99
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Surface AspectDf - Corrosion
Surface to fracture interface. The spring shows corrosion and pits.
46
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Corrosion
Scanning electron microscopy aspect of the region inside of a pit. The aspect is of a chemical attack, generated by the metabolic by-products of the adhered microorganism. The effect is of a localized dissolution and the granular tube microsctruture is revealed.
40
VIEW
ML00170 / Sep.2020
MIC in Aluminum Brass Tubes
M - Aluminum BrassP - Seamless tubeAp - MaritimeCd - Preferential Dissolution
Cm - Surface Aspect by SEMDf - Corrosion
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
Macrography of a typical corroded wire in a longitudinal section, showing loss of thickness by corrosion.
75
VIEW
ML00155 / Jan.2020
Failure of a Prestressed Concrete Steel Strand
M - High Carbon SteelP - Wire RopeAp - StructureCd - Corrosion Fatigue
Cm - NItal Etched MacroDf - Corrosion
Fractographic detail of the interconnected graphite flakes and corroded matrix.
50
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Fractography by SEMDf - Corrosion
Micrography at the scanning electron microscopy showing the deposits inside the crevice. The microanalysis by EDS revealed the presence of Fe, O, as well as Cl and S.
35
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Micrography by SEMDf - Corrosion
Corroded spots (shallow pits full of products) at the spring surface.
80
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Corrosion

More from these cases

ML00184 — Dissimilar Steels in a Threaded ConnectionM - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Not only the threads were corroded but all regions under the painting that was detached from the surface.
86
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Surface AspectDf - Corrosion
Macrosection of the valve body at the thread, showing the position where the fitting was installed.
84
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Transverse Section AspectDf - Corrosion
ML00172 — Brittle Fracture of a LAS Valve SpringM - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Aspect of the spring surface, with a layer of corroded products, and pits.
36
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - Surface Aspect by SEMDf - Corrosion
ML00155 — Failure of a Prestressed Concrete Steel StrandM - High Carbon SteelP - Wire RopeAp - StructureCd - Corrosion Fatigue
Micrography of a typical corroded wire, in a longitudinal section, showing loss of thickness by corrosion. The microstructure of the wire is predominantly pearlitic and the wire presents no coating, in any region.
54
VIEW
ML00155 / Jan.2020
Failure of a Prestressed Concrete Steel Strand
M - High Carbon SteelP - Wire RopeAp - StructureCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Corrosion
Micrography of a typical corroded wire, in a longitudinal section as polished, showing loss of thickness by corrosion. The loss of material is accelerated by the corrosion in "layers" associated to the strained microstructure.
43
VIEW
ML00155 / Jan.2020
Failure of a Prestressed Concrete Steel Strand
M - High Carbon SteelP - Wire RopeAp - StructureCd - Corrosion Fatigue
Cm - As polishedDf - Corrosion
Macro view of individual strand wires emerging from the anchorage fitting, most surfaces covered in reddish-brown corrosion product and several wire ends showing fracture.
4
VIEW
ML00155 / Jan.2020
Failure of a Prestressed Concrete Steel Strand
M - High Carbon SteelP - Wire RopeAp - StructureCd - Corrosion Fatigue
Cm - Aspect Before AnalysisDf - Corrosion
Cross-section at the wire surface showing a deep corrosion pit with branching attack adjacent to the longitudinally drawn metal texture.
4
VIEW
ML00155 / Jan.2020
Failure of a Prestressed Concrete Steel Strand
M - High Carbon SteelP - Wire RopeAp - StructureCd - Corrosion Fatigue
Cm - Aspect Before AnalysisDf - Corrosion
Cross-sectional view of a wire showing irregular corrosion pits penetrating inward from both surfaces.
4
VIEW
ML00155 / Jan.2020
Failure of a Prestressed Concrete Steel Strand
M - High Carbon SteelP - Wire RopeAp - StructureCd - Corrosion Fatigue
Cm - Aspect Before AnalysisDf - Corrosion

+6 more from this case →

ML00141 — Brittle Fracture of a Corroded Gray Cast IronM - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Micrographic detail of the corroded surface of the cast cylinder, with interconnected graphites and a notch effect.
30
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - As polished micrographyDf - Corrosion
Micrographic detail of the corroded surface of the cast cylinder in contact with treated water, as polished, showing that the corrosion occurs preferentially at the flake to matrix interfaces.
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 - Corrosion
Same position of the previous micrographic detail, at the internal surface of the cast cylinder in contact with treated water, after Nital etching, showing the corrosion at the flake to matrix interfaces.
30
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 - Corrosion
ML00137 — Brittle Fracture of a 15-5 PH Valve SpringM - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Corroded spots (shallow pits full of products) at the spring surface.
75
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Corrosion