Thermal Fatigue

3 cases · 54 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

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Polished cross-section showing rounded graphite nodules within a ferritic matrix, bordered by an irregular oxidized region at the surface edge.
909
VIEW
ML00001 / Dec.2017
Thermal Fatigue of Cast Iron
M - Nodular Cast IronP - CastAp - SiderurgyCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Oxide Layer
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
The micrography of the longitudinal section of the tube, close to OD, shows the paralel cracks, filled with oxides, perpendicular to the surface.
1441
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Close to the External Surface

More from these cases

ML00001 — Thermal Fatigue of Cast IronM - Nodular Cast IronP - CastAp - SiderurgyCd - Thermal Fatigue
Flat casting product presenting several thermal fatigue cracks all thorugh the surfaces. 1" thicknes.
171
VIEW
ML00001 / Dec.2017
Thermal Fatigue of Cast Iron
M - Nodular Cast IronP - CastAp - SiderurgyCd - Thermal Fatigue
Cm - Transverse Section AspectDf - Cracks Transverse to the Surface
Detail of figure 2, showing multiple fatigue cracks due to thermal cycles.
136
VIEW
ML00001 / Dec.2017
Thermal Fatigue of Cast Iron
M - Nodular Cast IronP - CastAp - SiderurgyCd - Thermal Fatigue
Cm - NItal Etched MacroDf - Cracks Transverse to the Surface
The 1" flat casting product presents a ferritic perlitic matrix and graphite nodules.
112
VIEW
ML00001 / Dec.2017
Thermal Fatigue of Cast Iron
M - Nodular Cast IronP - CastAp - SiderurgyCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Graphite in Nodules
Center of the flat casting product, presenting nodular graphite and ferritic perlitic matrix.
113
VIEW
ML00001 / Dec.2017
Thermal Fatigue of Cast Iron
M - Nodular Cast IronP - CastAp - SiderurgyCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Predominantly Ferritic Matrix
Nodular cast iron presenting a ferritic perlitic matrix.
109
VIEW
ML00001 / Dec.2017
Thermal Fatigue of Cast Iron
M - Nodular Cast IronP - CastAp - SiderurgyCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Matrix of ferrite and pearlite

+4 more from this case →

ML00119 — Thermal Fatigue of a Marine BoilerM - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Macrography of the plate (thickness 22mm, in horizontal position) to tube (thickness 12.5 mm, in vertical position) welded joint. The half V groove was welded from the top (position inside the combustion chamber) in five weld beads, and with a small fillet welded from the water side (ouside of the tube). Average hardness of the plate is 180HV1 (1kg), of the tube is 150HV1 and of the weld is 190HV1. Maximum hardness of the tube HAZ is 165HV1 and plate HAZ is 195HV1.
219
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - NItal Etched MacroDf - Welded Joint
Micrography of the plate in a longitudinal section, presenting a typical ferritic pearlitic structure, banded. The plate is 22 mm thick.
182
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 - Banded Structure
Micrography of the plate in a longitudinal section, presenting a typical ferritic pearlitic structure, banded.
165
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 - Ferrite and Pearlite
Micrographic detail of the ferritic pearlitic structure of the plate in the longitudinal section.
147
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 - Ferrite and Pearlite
Micrography of the weld metal in the center os the weld. Columnar grains (of the previous austenite) with primary ferrite in the grain boundaries; ferrite with aligned second phases and acicular ferrite, intragranular.
136
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 - Weld Metal

+16 more from this case →

ML00104 — Thermal Fatigue of a Boiler TubeM - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
The micrography of the longitudinal section of the tube, close to ID, shows the paralel cracks, filled with oxides, perpendicular to the surface.
229
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Close to the Internal Surface
The water wall tube, external diameter 60.3mm and thickness 3.9 mm, shows circunferential cracks in the middle of the section. Several other tubes have failed after 10 years in service.
716
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Aspect Before AnalysisDf - General View
Aspect of the internal surface of the tube after longitudinal cut. This position is out of the damage area and only a small amount of deposits is evident.
216
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Surface AspectDf - Internal Surface
Aspect of the internal surface of the tube after longitudinal cut. This position is at the damage area where a thick deposit is evident.
186
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Surface AspectDf - Internal Surface
Aspect of the external surface of the tube, presenting a large circunferential crack.
171
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Surface AspectDf - External Surface

+16 more from this case →