Low Carbon Steel

2 cases · 7 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Detail focus: Thermal Fatigue Cracks clear all

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Multiple thermal fatigue cracks at the welded joint between the smoke tube (vertical, internal diameter 248mm) and the tubesheet (horizontal, plate of 22 mm thickness). This is a view from the combustion chamber. The dye check tests revealed several parallel cracks.
1249
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - Aspect by NDTDf - Thermal Fatigue Cracks
Micrographic details of the longitudinal section of the tube, close to OD, showing paralel cracks, filled with oxides, perpendicular to the surface.
109
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Thermal Fatigue Cracks

More from these cases

ML00119 — Thermal Fatigue of a Marine BoilerM - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Higher magnification macrography (in a stereoscope) of the surface exposed to the combustion chamber, presenting multiple cracks perpendicular to the internal diamater of the tube (left side of the figure). The cracks are located in the tube and propagated into the tube wall and welded joint.
75
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - Surface AspectDf - Thermal Fatigue Cracks
Micrography of the cracking surface, presenting multiple cracks from the edge of the tube, typical of fatigue induced by stresses generated by differential expansion of the pipe in relation to the tubesheet, due to thermal cycles.
60
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Thermal Fatigue Cracks
ML00104 — Thermal Fatigue of a Boiler TubeM - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Micrographic details of the longitudinal section of the tube, close to ID, showing paralel cracks, filled with oxides, perpendicular to the surface.
99
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Thermal Fatigue Cracks
Micrography of the longitudinal section of the tube, close to OD, showing the cracks from the surface. The cracks are filled with oxides and slightly opened by corrosion.
84
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 - Thermal Fatigue Cracks
Micrography of the longitudinal section of the tube, close to ID, showing the cracks from the surface. The cracks are filled with oxides and there is still a layer of oxides at the internal surface, detached from the surface (probably during cleaning).
76
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 - Thermal Fatigue Cracks