Sampling and Analysis

6 cases · 29 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Damage Standard: ALLOY Capture method: Optical Microscope clear all

Sampling and Analysis — sub-branches

At the Surface 9Close to the External Surface 6Close to the Internal Surface 2External Surface 1In the Center of the Thickness 3Internal Surface 1Longitudinal Section 2T/4 of the external surface 2Transverse Section 3

Results

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Micrography of a longitudinal section of the sleeve, at the external surface where there are two layers of coating. The electrolytic etch evidenced the duplex stainless steel substrate (bottom of the figure) and the weave interface of the substrate and the first thermal spray layer, about 1 mm thick, in a stainless steel. The surface layer, of tugnsten carbide, about 0.2 mm thick, is black and not clearly visible in this figure.
50
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - NaOH Electrolytic Etched MicroDf - External Surface
Micrography of the plate section, as polished, close to the surface that suffered the impact. No evidences of damage.
26
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - As polished micrographyDf - At the Surface
Optical micrography of the transverse section of the drill collar, in the center of the thickness, presenting an uniform, granular, fully austenitic microstructure.
76
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 - Transverse Section
As polished micrography of the hydraulic line sample in the longitudinal section, close to the outer diameter, showing that the cracks are branched and thin, opened to the external surface.
58
VIEW
ML00095 / Sep.2017
MIC of a Riser Control Line
M - Austenitic Stainless SteelP - Fabrication WeldAp - Oil and GasCd - Brittle Behavior
Cm - Micrography by OMDf - Close to the External Surface
Micrography of a transverse section of the fitting, at the cracking position. Note the through wall cracking at the coarse austenitic ferritic structure.
43
VIEW
ML00094 / Sep.2017
MIC of a Subsea Hydraulic Line
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Behavior
Cm - NaOH Electrolytic Etched MicroDf - Transverse Section
Close to the camshaft lobe surface, the chilled casting presents a white cast iron structure. Primary carbides and ledeburite with a hardness level about 50 HRc.
102
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Close to the External Surface

More from these cases

ML00147 — WC Layer Detached from a Cast Lean DuplexM - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Micrography of the longitudinal section of the sleeve, at the interface between the substrate and the first thermal spray layer. The substrate (bottom of the figure) shows a ferritic-austenitic microstructure and detrimental phases that look like sigma. The thermal spray layer (top of the figure) presents the non-etched stainless steel, disposed in layers, with oxides (gray) and voids (black). The substrate is deformed in a thin layer at the interface.
38
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - NaOH Electrolytic Etched MicroDf - Close to the External Surface
Micrography of the longitudinal section of the cast sleeve in the middle of the thickness. The microstructure is coarse, austenitic ferritic.
34
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - NaOH Electrolytic Etched MicroDf - In the Center of the Thickness
Micrography of the longitudinal section of the cast sleeve, close to the internal diameter (ID). The microstructure is coarse, austenitic ferritic, and presents the same microstructure, ferritic and austenitic, all through the thickness.
21
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - NaOH Electrolytic Etched MicroDf - Internal Surface
ML00142 — Impact of a .308 Winchester on AR500 PlateM - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Micrography of the plate section, as polished, close to the surface that suffered the impact. At this magnification it is possible to see a deposit over the plate surface, but no evidences of damage in the plate.
25
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - As polished micrographyDf - At the Surface
Micrographic detail of the plate section, as polished, close to the surface that suffered the impact. The deposits at the surface are the melted bullet films.
23
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - As polished micrographyDf - At the Surface
Micrographic detail of the plate section, as polished, close to the surface that suffered the impact. The orange is the copper alloy melted film.
21
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - As polished micrographyDf - At the Surface
Micrographic detail of the plate section, as polished, close to the surface that suffered the impact. The lead alloy melted and formed this gray deposit.
20
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - As polished micrographyDf - At the Surface
Micrography of the plate section, close to the surface that suffered the impact. Smooth waves but no evidences of damage.
15
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - Nital Etched Micrography by OMDf - At the Surface

+3 more from this case →

ML00135 — MIC of a Non Magnetic Drilling ToolM - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Optical micrography of the transverse section of the drill collar, in the center of the thickness, presenting an uniform, granular, fully austenitic microstructure.
64
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 - Transverse Section
Optical micrography of the longitudinal section of the drill collar, in the center of the thickness, presenting slightly elongated grains of fully austenitic microstructure, cold worked. The material presented 38HRc hardness.
58
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 - Longitudinal Section
Optical micrography of the longitudinal section of the drill collar, in the center of the thickness, presenting slightly elongated grains of fully austenitic microstructure, cold worked.
62
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 - Longitudinal Section
Micrography of the damaged region close to the external surface, presenting a localized dissolution/corrosion.
58
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 External Surface
Micrography of the damaged region close to the external surface, presenting a localized dissolution/corrosion.
53
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 External Surface

+2 more from this case →

ML00060 — Brittle Fracture of a Chilled Cast Iron CamshaftM - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Micrographic detail of the chilled structure. Primary carbides, ledeburite and perlite islands.
79
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
In the center of the shaft thickness the structure is perlitic with graphite in flakes, but there are also islands of ledeburite.
62
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrographic detail of the structure in the center of the shaft thickness. Perlitic matrix with graphite in flakes, and ledeburite islands.
53
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
In the intermediary position of the shaft thickness (T/4) the amount of perlite increases in the matrix and primary carbides decreases compared to the chilled surface.
54
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - T/4 of the external surface
Micrographic detail of the intermediary position of the shaft thickness (T/4). The amount of perlite increases in the matrix and primary carbides decreases compared with the chilled surface.
55
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - T/4 of the external surface