Atlas

6 cases · 28 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Application: Ship Capture method: As polished micrography clear all

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Micrography of a longitudinal section of the spring, at the surface, indicating that there are multiple intergranular cracks initiating from the pit.
26
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - As polished micrographyDf - Multiple cracks
Micrography of a transverse section of the bent tube, external surface (OD) to the top and internal surface (ID) to the bottom of the figure. At the through wall cracking position, the external surface presented a layer of intergranular corrosion.
95
VIEW
ML00165 / Jul.2020
SCC of Aluminum Bronze Heating Coil
M - Aluminum BronzeP - Seamless tubeAp - Oil and GasCd - Stress Corrosion
Cm - As polished micrographyDf - Cracking
Micrography of a longitudinal section of the sleeve, in a region where the two layers applied by thermal spray are sound, not detached. The grey layer (200 micros) is the tugnsten carbide; and the white layer (1000 microns) is a stainless steel. The substrate is white in the bottom of the figure.
24
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - As polished micrographyDf - Thermal Spray Layer
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 a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
72
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 - As polished micrographyDf - Intergranular Cracking
Micrography of the transverse section of the platesheet at the interface between the corroded and the non-corroded regions. The micrography is in the as polished condition.
140
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - As polished micrographyDf - Preferential Dissolution

More from these cases

ML00172 — Brittle Fracture of a LAS Valve SpringM - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Micrographic aspect of the multiple intergranular cracks, initiating from the bottom of a pit.
25
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - As polished micrographyDf - Intergranular Cracking
Micrographic detail of the intergranular cracks, initiating from the bottom of a pit.
29
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - As polished micrographyDf - Intergranular Cracking
ML00165 — SCC of Aluminum Bronze Heating CoilM - Aluminum BronzeP - Seamless tubeAp - Oil and GasCd - Stress Corrosion
Micrographic detail of the external side of the bent tube, as polished, showing detachement of several grains due to the intergranular corrosion layer. The corroded layer is about 200 microns thick at this position.
89
VIEW
ML00165 / Jul.2020
SCC of Aluminum Bronze Heating Coil
M - Aluminum BronzeP - Seamless tubeAp - Oil and GasCd - Stress Corrosion
Cm - As polished micrographyDf - Intergranular Corrosion
Micrographic detail of the external side of the tube, showing the layer of intergranular corrosion and the through ewall integranular stress corrosion cracking.
88
VIEW
ML00165 / Jul.2020
SCC of Aluminum Bronze Heating Coil
M - Aluminum BronzeP - Seamless tubeAp - Oil and GasCd - Stress Corrosion
Cm - As polished micrographyDf - Through Wall Cracking
ML00147 — WC Layer Detached from a Cast Lean DuplexM - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Micrography of a longitudinal section of the sleeve, in a region where the surface layer starts detachment. This grey layer is the tugnsten carbide; and the white layer (1000 microns) is a stainless steel. In this case the first TS layer is sound. The substrate is white in the bottom of the figure.
20
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - As polished micrographyDf - Layer Detachment
Micrography of a longitudinal section of the sleeve, in a region where the surface layer was completely removed. In this position only the stainless steel layer is at the surface. That is why the sealing condition was lost. The substrate is white in the bottom of the figure.
19
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - As polished micrographyDf - Layer Detachment
Micrographic detail of a longitudinal section of the sleeve, in a region where the WC (tungsten carbibe) surface layer was degradated and partially removed.
17
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - As polished micrographyDf - Layer Detachment
Micrographic detail of the WC (tungsten carbibe) surface layer, degradated and partially removed.
16
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - As polished micrographyDf - Layer Detachment
Micrography of a longitudinal section of the sleeve, in a region where the surface layer was completely removed. In this position only the stainless steel layer, that is porous and full of oxides, is at the surface. That is why the sealing condition was lost.
17
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - As polished micrographyDf - Thermal Spray Layer

+1 more from this case →

ML00141 — Brittle Fracture of a Corroded Gray Cast IronM - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Micrographic aspect, as polished, of the cast cylinder section at the fracture position (top of the figure), in the center of the thickness. It is possible to see a mixture of large graphite flakes and rosette grouping flakes.
80
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - As polished micrographyDf - In the Center of the Thickness
Micrographic aspect, as polished, of the cast cylinder section at the fracture position (top of the figure), close to the external surface (left side). It is possible to see smaller graphite flakes, interdendritic .
79
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 External 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 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 painted external surface of the cast cylinder.
26
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 External Surface

+1 more from this case →

ML00137 — Brittle Fracture of a 15-5 PH Valve SpringM - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Micrographic detail of a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
65
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 - As polished micrographyDf - Intergranular Cracking
ML00125 — Dezincification of a Cooler TubesheetM - BrassP - PlateAp - ShipCd - Preferential Dissolution
Micrography of the transverse section of the platesheet showing that part of the material (right side in the top of the figure) was lost (corroded).
129
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - As polished micrographyDf - Preferential Dissolution
Micrographic detail of the dezincification effect, where the beta phase is preferentially corroded, leaving a cooper rich phase (red) that is porous and easily cracks.
121
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - As polished micrographyDf - Dezincification
Micrographic detail of the dezincification effect, where the beta phase is preferentially corroded, leaving a cooper rich phase (red) that is porous and easily cracks.
130
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - As polished micrographyDf - Cracks
Micrography showing detachment of material at the surface of the platesheet. The cracks are associated to the dezincification effect, where the beta phase was preferentially corroded and became a weak porous layer.
113
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - As polished micrographyDf - Crack
Micrography presenting the interface between the layer where the dezincification occurred (top of the figure) and the region where the material was not yet corroded (bottom of the figure).
86
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - As polished micrographyDf - Dezincification