Optical Microscope

13 cases · 104 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Corrosion Standard: ASTM clear all

Optical Microscope — sub-branches

Kalling Etched Micrography by OM 26Micrography by OM 10Micrography by OM using A262 Method A 22NaOH Electrolytic Etched Micro 6Nital Etched Micrography by OM 33Oxalic Acid Electrolytic Etch 7

Results

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The micrography of the transverse section of the plate, as polished, close to the surface. The material presents intergranular corrosion and some grains were lost.
1184
VIEW
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OMDf - Intergranular Corrosion
The micrography of a longitudinal section of the pipe, close to the internal surface, shows a general corrosion mechanism (with slow wall thickness loss), although the graphite/matrix interface is corroded preferentially.
569
VIEW
ML00034 / Apr.2017
45 Years Old Acquaduct Grey Cast Iron
M - Gray Cast ironP - Centrifugally Cast PipeAp - AcquaductCd - General Corrosion
Cm - Nital Etched Micrography by OMDf - Corrosion
Transverse section of the fitting that suffered a longitudinal cracking. As polished. The wrought fitting has suffered intergranular stress corrosion cracking from the internal surface, exposed to hot caustic environment.
566
VIEW
ML00011 / Oct.2017
Intergranular SCC of Pure Nickel
M - Unalloyed NickelP - Wrought FittingAp - Chemical IndustryCd - Stress Corrosion
Cm - Micrography by OMDf - Intergranular Cracking
Micrography of a transverse section of the pipe, presenting the pitting corrosion. As polished.
310
VIEW
ML00014 / Apr.2017
Pitting Corrosion in 316SS Pipe
M - Austenitic Stainless SteelP - Seamless PipeAp - FPSOCd - Pitting Corrosion
Cm - Micrography by OMDf - Pitting
Macrography transverse to the circunferential weld, longitudinal to the piping, presenting the location, a little far from the welded joint margin, where the through wall cracking is positioned.
160
VIEW
ML00002 / Jan.2018
Preferential Dissolution and Cracks in SDSS
M - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Cm - NaOH Electrolytic Etched MicroDf - Through Wall Cracking

More from these cases

ML00015 — Intergranular Corrosion of 304SS PlateM - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Microstructure of the plate in the center of the ¼” thickness. Equiaxed austenitic grains with delta ferrite stringers and grain boundary carbide precipitation (sensitization).
303
VIEW
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OM using A262 Method ADf - Intergranular Precipitation
Microstructure of the plate in the center of the ¼” thickness. Equiaxed austenitic grains with delta ferrite stringers and grain boundary carbide precipitation (sensitization).
201
VIEW
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OM using A262 Method ADf - Intergranular Precipitation
Micrographic aspect of a longitudinal section of the plate, close to the surface, in a region where it was detected intergranular corrosion up to 0,5 mm depth. As polished.
188
VIEW
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OMDf - Intergranular Corrosion
Micrographic detail of intergranular corrosion, up to 0,5 mm depth. As polished.
171
VIEW
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OMDf - Intergranular Corrosion
Micrographic aspect of a longitudinal section of the plate, close to the surface, in a region with intergranular corrosion. Several loose grains were removed, indicating that the structure was embrittled by the intergranular corrosion.
171
VIEW
ML00015 / Oct.2017
Intergranular Corrosion of 304SS Plate
M - Austenitic Stainless SteelP - Rolled PlateAp - RefineryCd - Intergranular Corrosion
Cm - Micrography by OM using A262 Method ADf - Intergranular Corrosion

+4 more from this case →

ML00034 — 45 Years Old Acquaduct Grey Cast IronM - Gray Cast ironP - Centrifugally Cast PipeAp - AcquaductCd - General Corrosion
Micrographic detail of the graphite/matrix interface corrosion, leading to a general corrosion loss.
189
VIEW
ML00034 / Apr.2017
45 Years Old Acquaduct Grey Cast Iron
M - Gray Cast ironP - Centrifugally Cast PipeAp - AcquaductCd - General Corrosion
Cm - Nital Etched Micrography by OMDf - Graphite in Flakes
Micrography of the longitudinal section of the pipe, close to the internal surface, showing graphite in flakes and ferritic matrix with small regions of perlite.
231
VIEW
ML00034 / Apr.2017
45 Years Old Acquaduct Grey Cast Iron
M - Gray Cast ironP - Centrifugally Cast PipeAp - AcquaductCd - General Corrosion
Cm - Nital Etched Micrography by OMDf - Predominantly Ferritic Matrix
Micrography of the longitudinal section of the pipe, close to the internal surface, showing graphite in flakes and ferritic matrix with small regions of perlite and eutetic in the middle of the perlite colonies.
192
VIEW
ML00034 / Apr.2017
45 Years Old Acquaduct Grey Cast Iron
M - Gray Cast ironP - Centrifugally Cast PipeAp - AcquaductCd - General Corrosion
Cm - Nital Etched Micrography by OMDf - Predominantly Ferritic Matrix
Micrography of the longitudinal section of the pipe, in the center of the thickness. Graphite in flakes and ferritic matrix with small regions of perlite.
179
VIEW
ML00034 / Apr.2017
45 Years Old Acquaduct Grey Cast Iron
M - Gray Cast ironP - Centrifugally Cast PipeAp - AcquaductCd - General Corrosion
Cm - Nital Etched Micrography by OMDf - Predominantly Ferritic Matrix
Micrography of the longitudinal section of the pipe, in the center of the thickness. Graphite in flakes and ferritic matrix with small regions of perlite.
162
VIEW
ML00034 / Apr.2017
45 Years Old Acquaduct Grey Cast Iron
M - Gray Cast ironP - Centrifugally Cast PipeAp - AcquaductCd - General Corrosion
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite

+4 more from this case →

ML00011 — Intergranular SCC of Pure NickelM - Unalloyed NickelP - Wrought FittingAp - Chemical IndustryCd - Stress Corrosion
Microstructure of the fitting in the transverse section, presenting a granular Ni austenitic structure. No evidences of any phase in the grain boundaries.
114
VIEW
ML00011 / Oct.2017
Intergranular SCC of Pure Nickel
M - Unalloyed NickelP - Wrought FittingAp - Chemical IndustryCd - Stress Corrosion
Cm - Kalling Etched Micrography by OMDf - Austenite
Microstructure of the fitting in the transverse section, presenting a granular Ni austenitic structure. No evidences of any phase in the grain boundaries.
110
VIEW
ML00011 / Oct.2017
Intergranular SCC of Pure Nickel
M - Unalloyed NickelP - Wrought FittingAp - Chemical IndustryCd - Stress Corrosion
Cm - Kalling Etched Micrography by OMDf - Austenite
Microstructure of the fitting in the transverse section, presenting a granular Ni austenitic structure. No evidences of any phase in the grain boundaries.
96
VIEW
ML00011 / Oct.2017
Intergranular SCC of Pure Nickel
M - Unalloyed NickelP - Wrought FittingAp - Chemical IndustryCd - Stress Corrosion
Cm - Kalling Etched Micrography by OMDf - Austenite
Transverse section of the fitting that suffered a longitudinal cracking. As polished. The wrought fitting has suffered intergranular stress corrosion cracking from the internal surface, exposed to hot caustic environment.
70
VIEW
ML00011 / Oct.2017
Intergranular SCC of Pure Nickel
M - Unalloyed NickelP - Wrought FittingAp - Chemical IndustryCd - Stress Corrosion
Cm - Micrography by OMDf - Intergranular Cracking
Transverse section of the fitting that suffered a longitudinal cracking. As polished. The wrought fitting has suffered intergranular stress corrosion cracking from the internal surface, exposed to hot caustic environment.
59
VIEW
ML00011 / Oct.2017
Intergranular SCC of Pure Nickel
M - Unalloyed NickelP - Wrought FittingAp - Chemical IndustryCd - Stress Corrosion
Cm - Micrography by OMDf - Corrosion Cracking

+2 more from this case →

ML00014 — Pitting Corrosion in 316SS PipeM - Austenitic Stainless SteelP - Seamless PipeAp - FPSOCd - Pitting Corrosion
Austenitic structure at the transverse section of the pipe, free from carbides.
277
VIEW
ML00014 / Apr.2017
Pitting Corrosion in 316SS Pipe
M - Austenitic Stainless SteelP - Seamless PipeAp - FPSOCd - Pitting Corrosion
Cm - Micrography by OM using A262 Method ADf - Austenite
Austenitic structure, free from carbides, exactly in the region of the pitting, indicating that the corrosion is not associated to the material microstructure.
261
VIEW
ML00014 / Apr.2017
Pitting Corrosion in 316SS Pipe
M - Austenitic Stainless SteelP - Seamless PipeAp - FPSOCd - Pitting Corrosion
Cm - Micrography by OM using A262 Method ADf - Austenite
ML00002 — Preferential Dissolution and Cracks in SDSSM - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Longitudinal section micrography at the cracked position, close to the external surface of the flange, showing cracks transverse to the thickness, associated to the microstructure.
147
VIEW
ML00002 / Jan.2018
Preferential Dissolution and Cracks in SDSS
M - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Cm - NaOH Electrolytic Etched MicroDf - Cracks Transverse to the Surface
Longitudinal section micrography at the cracked position, close to the internal surface of the flange (exposed to the corrosive fluid), showing preferential dissolution associated to the microstructure.
133
VIEW
ML00002 / Jan.2018
Preferential Dissolution and Cracks in SDSS
M - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Cm - NaOH Electrolytic Etched MicroDf - Preferential Dissolution
Micrography of the flange in the longitudinal section. The flange microstructure is ferritic austenitic, presenting a coarse structure.
102
VIEW
ML00002 / Jan.2018
Preferential Dissolution and Cracks in SDSS
M - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Cm - NaOH Electrolytic Etched MicroDf - Coarse Structure
Micrographic detail of the flange microstructure in the longitudinal section. The flange is ferritic austenitic, presenting 70% of austenite. In the ferrite network there are evidences of precipitation/formation of detrimental phases.
113
VIEW
ML00002 / Jan.2018
Preferential Dissolution and Cracks in SDSS
M - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Cm - NaOH Electrolytic Etched MicroDf - Duplex structure
Micrographic detail of the flange microstructure in the longitudinal section. The flange is ferritic austenitic, presenting 70% of austenite. In the ferrite network there are evidences of precipitation/formation of detrimental phases.
100
VIEW
ML00002 / Jan.2018
Preferential Dissolution and Cracks in SDSS
M - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Cm - NaOH Electrolytic Etched MicroDf - Duplex structure