Pressure Vessel

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Crevice Corrosion in a Subsea System — Aspect Before Analysis

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Aspect of a crevice corrosion of the flange, under the bolt head, showing evidences that the cathodic protection system was not connected to the stainless steel instrument.
1434
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Aspect Before AnalysisDf - Localized Corrosion
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 detail of the fatigue cracking at the margin of the flange to shell fillet weld.
484
VIEW
ML00050 / Nov.2017
Fatigue Failure of a 316SS Pressure Stabilizer
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
Cm - Micrography by OM using A262 Method ADf - Fatigue Crack
The macrography of a longitudinal section of the shell plate (sample removed from the boiler), at the position of the fillet weld (sealing weld) with a tube, where surface welding repairs created conditions for cracking the base material in a transgranular morphology. Several cracks were identify starting from the steam drum internal surface.
448
VIEW
ML00019 / Apr.2017
Transgranular SCC in Boiler Steam Drum
M - CMn SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - Transverse Section AspectDf - Cracks
Typical branched stress corrosion cracks in a low carbon steel, ferritic-pertlitic structure. The cracks are filled with corrosion products.
771
VIEW
ML00018 / Apr.2017
SCC in Boiler Steam Drum
M - Low Carbon SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Branched Cracks
Steam drum presenting cracks in the shell, connecting tube holes.
1704
VIEW
ML00020 / Apr.2017
Intergranular SCC in Boiler Steam Drum Repair
M - Low Carbon SteelP - Repair WeldAp - BoilerCd - Stress Corrosion
Cm - Aspect Before AnalysisDf - Cracking
The internal surface of the 2 1/2" thickness plate drum was welded to attach a baffle plate (1/4" thick) using two fillets (one in each side of the plate to shell), but the welding procedure was not suitable since cracks appeared underbead, although they were detected only after 6 month in operation, when the baffle was removed. The picture shows a macrography of the surface, with the cracking.
698
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - NItal Etched MacroDf - Cracking

More from these cases

ML00122 — Crevice Corrosion in a Subsea SystemM - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Flanged case, 640mm long. The photo presents a general view of the instrumentation system, destroyed after only 6 months in subsea service. The system was manufactured using only 316 stainless steel and the case was 20 mm thick.
335
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Aspect Before AnalysisDf - General View
Aspect of the instrument system after disassembling. The internal part of the case, where the electronic device was operating, was wet by seawater and failed to send signals to the surface.
258
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Aspect Before AnalysisDf - General View
Detail of the electronic device after removing the external case. It is corroded because seawater entered in the equipment that was pressurized from the external sea environment.
228
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Aspect Before AnalysisDf - Corrosion
After a longitudinal cut of the case it was possible to see that a localized corrosion has occurred associated to the regions where there were sealed holes, plugged, in a crevice condition, not related to any welded position.
193
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Transverse Section AspectDf - Corrosion
Micrography of the case, observed in the center of the thickness, showing an equiaxial granular austenitic microstructure, free from carbides. The structure is typical of a 316 SS, in a solution annealed condition.
176
VIEW
ML00122 / Feb.2018
Crevice Corrosion in a Subsea System
M - Austenitic Stainless SteelP - CaseAp - Oil and GasCd - Crevice
Cm - Micrography by OM using A262 Method ADf - Austenite

+11 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 →

ML00050 — Fatigue Failure of a 316SS Pressure StabilizerM - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
Aspect of the equipment presenting a through wall cracking at the margin of the fillet weld.
142
VIEW
ML00050 / Nov.2017
Fatigue Failure of a 316SS Pressure Stabilizer
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
Cm - Aspect Before AnalysisDf - Cracking
Macrography of the welded joint between the flange and the shell, indicating the position where the cracking was detected, at 90°.
116
VIEW
ML00050 / Nov.2017
Fatigue Failure of a 316SS Pressure Stabilizer
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
Cm - Macro Oxalic Acid Electrolytic EtchedDf - Welded Joint
The shell plate micrography showed an austenitic structure.
101
VIEW
ML00050 / Nov.2017
Fatigue Failure of a 316SS Pressure Stabilizer
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
Cm - Micrography by OM using A262 Method ADf - Austenite
The macrography of a transverse section of the shell to flange weld (Lepto's etch) shows that the cracking occurred through the shell plate thickness, at the margin of the fillet weld.
93
VIEW
ML00050 / Nov.2017
Fatigue Failure of a 316SS Pressure Stabilizer
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
Cm - Transverse Section AspectDf - Cracking
Fracture surface after opening the shell cracking, presenting fatigue striation. The fracture presents also foreign particles.
132
VIEW
ML00050 / Nov.2017
Fatigue Failure of a 316SS Pressure Stabilizer
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
Cm - Fractography by SEMDf - Fatigue Striation

+3 more from this case →

ML00019 — Transgranular SCC in Boiler Steam DrumM - CMn SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Schematic drawing presenting the longitudinal section of the shell plate (sample removed from the boiler), at the position of the fillet weld (sealing weld) with a tube, where surface welding repairs created conditions for cracking the base material in a transgranular morphology. Several cracks were identify starting from the steam drum internal surface.
120
VIEW
ML00019 / Apr.2017
Transgranular SCC in Boiler Steam Drum
M - CMn SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - Identification drawingDf - Cracks
Micrography of a transverse section of the shell plate in a cracked position showing the transgranular morphology of the stress corrosion cracks.
167
VIEW
ML00019 / Apr.2017
Transgranular SCC in Boiler Steam Drum
M - CMn SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by SEMDf - Transgranular Cracking
Micrography of the shell plate in the longitudinal section. Ferritic-perlitic microstructure.
96
VIEW
ML00019 / Apr.2017
Transgranular SCC in Boiler Steam Drum
M - CMn SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the shell plate in the longitudinal section. Ferritic-perlitic microstructure.
89
VIEW
ML00019 / Apr.2017
Transgranular SCC in Boiler Steam Drum
M - CMn SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of the cracking showing the branched nature, typical of a stress corrosion cracking. The cracks started from the internal surface of the steam drum.
94
VIEW
ML00019 / Apr.2017
Transgranular SCC in Boiler Steam Drum
M - CMn SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Branched Cracks

+4 more from this case →

ML00018 — SCC in Boiler Steam DrumM - Low Carbon SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Ferritic perlitic structure of the shell plate.
207
VIEW
ML00018 / Apr.2017
SCC in Boiler Steam Drum
M - Low Carbon SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Macrography of a transverse section of the steam drum sample that was removed after the inspection had detected multiple cracks propagating into the thickness, more than 50% deep in the thickness.
190
VIEW
ML00018 / Apr.2017
SCC in Boiler Steam Drum
M - Low Carbon SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - NItal Etched MacroDf - Transverse Section
Micrography of the crack at the internal surface of the steam drum. The shell plate presents a ferritic perlitic structure.
162
VIEW
ML00018 / Apr.2017
SCC in Boiler Steam Drum
M - Low Carbon SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Branched Cracks
Micrography of a crack, in a sample as polished, presenting the opened crack.
144
VIEW
ML00018 / Apr.2017
SCC in Boiler Steam Drum
M - Low Carbon SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - Micrography by OMDf - Branched Cracks
Stress corrosion cracks propagating in the ferritic-perlitic structure.
120
VIEW
ML00018 / Apr.2017
SCC in Boiler Steam Drum
M - Low Carbon SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Branched Cracks

+3 more from this case →

ML00020 — Intergranular SCC in Boiler Steam Drum RepairM - Low Carbon SteelP - Repair WeldAp - BoilerCd - Stress Corrosion
Aspect of the drum shell after removing the tubes and macroetching, indicating that the cracks were located in repair welded regions.
342
VIEW
ML00020 / Apr.2017
Intergranular SCC in Boiler Steam Drum Repair
M - Low Carbon SteelP - Repair WeldAp - BoilerCd - Stress Corrosion
Cm - Aspect by NDTDf - Cracks
A small sample was removed from the steam drum and the micrography shows that the cracks are intergranular (previous austenite) and located in the weld metal.
285
VIEW
ML00020 / Apr.2017
Intergranular SCC in Boiler Steam Drum Repair
M - Low Carbon SteelP - Repair WeldAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Corrosion Cracking
The micrography of the small sample removed from the steam drum shows that the cracks are intergranular (previous austenite) and located in the weld metal.
274
VIEW
ML00020 / Apr.2017
Intergranular SCC in Boiler Steam Drum Repair
M - Low Carbon SteelP - Repair WeldAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Corrosion Cracking
Secondary cracks in the weld metal showing an intergranular morphology. Stress Corrosion Cracking.
249
VIEW
ML00020 / Apr.2017
Intergranular SCC in Boiler Steam Drum Repair
M - Low Carbon SteelP - Repair WeldAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Corrosion Cracking
Detail of the secondary cracks in the weld metal with intergranular morphology. Stress Corrosion Cracking.
251
VIEW
ML00020 / Apr.2017
Intergranular SCC in Boiler Steam Drum Repair
M - Low Carbon SteelP - Repair WeldAp - BoilerCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Corrosion Cracking

+1 more from this case →

ML00008 — Cold Cracks in CMn Steel Pressure VesselM - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Micrography of a longitudinal section of the shell plate base metal, presenting a typical ferritic-perlitic microstructure.
149
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Higher magnification of the ferritic-perlitic microstructure of the shell plate in the longitudinal section.
129
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Cold cracking of the fillet weld adopted to attach a flat support into a vessel shell in the internal side, using an unsuitable welding procedure that created a too high hardness HAZ.
123
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks
Cold cracking of the fillet weld adopted to attach a flat support into a vessel shell in the internal side, using an unsuitable welding procedure that created a too high hardness HAZ. The cracks are mainly located at the fusion line.
118
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks
Cold cracking of the fillet weld adopted to attach a flat support into a vessel shell in the internal side, using an unsuitable welding procedure that created a too high hardness HAZ. Several internal cracks at the fusion line.
101
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks

+2 more from this case →