Optical Microscope

67 cases · 615 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Damage Standard: UNS clear all

Optical Microscope — sub-branches

As polished micrography 57Chromic Acid Electrolytic Etched 1Eletrolytically Etched Micrography by OM 5FeCl3+HCl+Ethanol Etched Micro 15FeCl3+HCl+H2O Etched Micro 18Glyceregia Etched Micrography by OM 1H2SO4+HNO3+H3PO4 Etched Micro 1Kalling Etched Micrography by OM 135Keller Etched Micrography by OM 21Kroll Etched Micrography by OM 5Micrography by OM 36Micrography by OM using A262 Method A 65Micrography by OM, HF + HNO3 + H2O etch 2NaOH Electrolytic Etched Micro 49Nital Etched Micrography by OM 190Oxalic Acid Electrolytic Etch 14

Results

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Through wall cracking in the longitudinal seam weld of the fitting. Several cracks, longitudinal to the weld, were created by the connection of voids in the weld metal, associated to a strong microstructural evolution.
191
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - Cracks
Micrography of the plate material presenting a granular austenitic structure, free from precipitation.
122
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Eletrolytically Etched Micrography by OMDf - Austenite
Micrographic aspect of the corrosion damage in a section transverse to the pitting.
167
VIEW
ML00054 / Dec.2018
Cutlery Corrosion
M - Martensitic Stainless SteelP - Foodstuff ArticleAp - KitchenCd - Pitting Corrosion
Cm - Kalling Etched Micrography by OMDf - Pitting
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
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
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
The micrography of a transverse section of the shaft shows the granular austenitic structure close to the surface of the shaft.
67
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - At the Surface
The cast iron microstructure is predominatly ferritic with graphite nodules.
169
VIEW
ML00040 / Apr.2017
Brittle Fracture of a Valve Stem
M - Nodular Cast IronP - Valve StemAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Graphite in Nodules

More from these cases

ML00061 — Creep in a Seam Weld of a 304H SS FittingM - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Micrography of a longitudinal section of the fitting, at the base metal, presenting an austenitic structure with intergranular and transgranular precipitation as a result of microstructural evolution.
44
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - Base Metal
Micrographic detail of the fitting base metal, presenting an austenitic structure with intergranular and transgranular precipitation as a result of microstructural evolution.
40
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - Base Metal
Micrography of a transverse section of the seam weld, close to the internal surface, presenting several cracks perpendicular to the thickness.
37
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - Close to the Internal Surface
Micrographic detail of the seam weld close to the internal surface, presenting the needles that are the result of microsctructural evolution and cracks filled with oxides.
36
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - Close to the Internal Surface
Micrography of a transverse section of the seam weld, in the middle of the thickness, presenting several parallel cracks.
27
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - In the Center of the Thickness

+7 more from this case →

ML00051 — Chloride SCC of 316 Heat Exchanger PlateM - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Micrographic detail of the austenitic microstructure of the heat exchanger plate, free from carbides that suggest the adoption of a material in a solution annealed condition, although the high hardness level indicates cold working.
109
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Eletrolytically Etched Micrography by OMDf - Austenite
Micrography presenting the transgranular morphology of the stress corrosion cracks of the austenitic plate. EDS analysis at the plate surface indicated high Cl peaks.
111
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Eletrolytically Etched Micrography by OMDf - Corrosion Cracking
Micrographic detail of a branch transgranular crack typical of CSCC. Moreover, there is no evidence of intergranular precipitation.
99
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Micrography by OM using A262 Method ADf - Corrosion Cracking
ML00050 — Fatigue Failure of a 316SS Pressure StabilizerM - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
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 micrography of the welded joint between the flange and the shell, in a region that was through wall cracked, the fracture propagating in the shell plate base metal.
74
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 - Welded Joint
The micrography of the welded joint between the flange and the shell, in a region that was not yet macroscopically cracked, presented a fatigue crack from the margin of the fillet weld.
71
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 - Welded Joint
ML00020 — Intergranular SCC in Boiler Steam Drum RepairM - Low Carbon SteelP - Repair WeldAp - BoilerCd - Stress Corrosion
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
Detail of the intergranular stress corrosion cracking of the drum shell weld repair.
217
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
ML00008 — Cold Cracks in CMn Steel Pressure VesselM - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
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
Cold cracking of the fillet weld adopted to attach a flat support into a vessel shell using an unsuitable welding procedure, with a low preheating and no PWHT. Cracks propagated in the heat affected zone.
99
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

+1 more from this case →

ML00041 — Fatigue Fracture of Inconel 718 Spline ShaftM - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Micrographic detail of the granular austenitic structure close to the surface of the shaft.
64
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - At the Surface
Granular austenitic structure close to the surface of the shaft.
61
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - Austenite
The micrography of a transverse section of the shaft shows a duplex grain size structure in the center of the shaft.
49
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - In the Center of the Thickness
The micrography of a transverse section of the shaft shows a duplex grain size structure in the center of the shaft. This conditions was probably generated due to the delta phase presented in segregated bands in the center of the original bar.
56
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - In the Center of the Thickness
Duplex grain size structure, austenitic. The small grains are probably due to the arresting effect of the delta phase during fabrication in high temperature.
47
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - Duplex structure

+2 more from this case →

ML00040 — Brittle Fracture of a Valve StemM - Nodular Cast IronP - Valve StemAp - ShipCd - Brittle Fracture
The micrography of the stem at the fracture region shows a flat fracture with transgranular clevage at the ferritic structure.
137
VIEW
ML00040 / Apr.2017
Brittle Fracture of a Valve Stem
M - Nodular Cast IronP - Valve StemAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Fracture
Micrography presenting a detail of the fracture surface opening to the graphite nodules.
139
VIEW
ML00040 / Apr.2017
Brittle Fracture of a Valve Stem
M - Nodular Cast IronP - Valve StemAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Fracture