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2 cases · 11 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Microstructure: Degradated Capture method: Optical Microscope Detail focus: Microstructure clear all

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Micrography of a longitudinal section of the tube, 200 mm far from the cracked region, in the center of the thickness (3.9 mm) showing a granular ferritic-perlitic structure.
139
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
13Cr SS in the longitudinal section, at the collapsed region. Detail of the non uniform structure (ferritic matrix and decorated prior austenite grain boundaries) that evidences an usuitable heat treatment during fabrication, and explains the material low strenght.
48
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Prior Austenite Boundaries Decorated

More from these cases

ML00104 — Thermal Fatigue of a Boiler TubeM - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Micrographic detail of a longitudinal section of the tube, 200 mm far from the cracked region, in the center of the thickness (3.9 mm). Feritic perlitic structure.
113
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of a longitudinal section of the tube, at the cracked region, in the center of the thickness, showing an evolution of the perlitic structure into carbides.
110
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Coalesced structure
Micrographic detail of a longitudinal section of the tube, at the cracked region, in the center of the thickness. The pearlitic structure was already degratated into globular carbides.
101
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Coalesced structure
Micrography of the longitudinal section of the tube, close to OD, showing no damage in a section about 200mm far from the cracked region.
92
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the thermal fatigue cracking, assisted by corrosion, at the OD, in a longitudinal section. The microstructure is ferrite with coalescing carbides.
77
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Coalesced structure

+2 more from this case →

ML00039 — Collapse in Tubular 13CrM - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
The micrography of the 13Cr SS in the transverse section, at the collapsed region, shows a ferritic matrix structure (overtempered) with the previous austenite grain boundaries decorated by phases (carbides and probably martensite islands), indicating that the material was exposed to a high tempering temperature that created a partial austenitizing condition. It explains the material low toughness and lower strenght (than required).
32
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Overtempered Structure
The micrography of the 13Cr SS in the transverse section, far from the collapsed region, shows a uniform tempered martensitic structure.
31
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Martensite