Nital Etched Micrography by SEM

9 cases · 27 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Microstructure: Ferritic pearlitic clear all

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Detail by scanning electron microscopy of the pits in the metallographic longitudinal section of the clamp, at the surface (left side of the image). There are cracks emanating from the pits.
27
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Nital Etched Micrography by SEMDf - Crack
Micrographic detail, by scanning electron micrography, of the pitting corrosion generating cracks, typical of a corrosion fatigue mechanism.
156
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - Nital Etched Micrography by SEMDf - Pitting
Micrography of the weld metal in the last bead, presenting previous austenite columnar grains, primary ferrite in the grain boundaries, some regions of ferrite with aligned second phases and acicular ferrite.
58
VIEW
ML00153 / Jan.2019
X52 in a Tubular Structure
M - CMn SteelP - Seamless PipeAp - StructureCd - Qualified
Cm - Nital Etched Micrography by SEMDf - Weld Metal
Micrography of the plate section, in the middle of the plate in a position where the projectile did not affect. Ferritic-pearlitic structure.
55
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by SEMDf - Ferrite and Pearlite
Micrography of the longitudinal section of the cylinder, at the external diameter (right side of the figure), presenting smaller interdendritic graphite flakes in a ferritic-perlitic matrix. This surface is painted.
32
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Nital Etched Micrography by SEMDf - Graphite in Flakes
Micrography of the seam welded joint, autogenous. The localized dissolution occurrs exactly at the weld metal that presents a bainitic structure and Vickers (100g) microhardness values about 230HV, compared to the heat affected zone presenting average of 202 HV and the base metal presenting average of 180HV.
59
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by SEMDf - Welded Joint
Micrographic detail of the bainitic structure at the HAZ of the carbon steel plate, by scanning electron microscopy.
40
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Heat Affected Zone
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

More from these cases

ML00171 — Corrosion Fatigue of U Bolt Pipe ClampM - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Metallographic aspect of one secondary cracking, paralell to the fracture surface, growthing with an irregular path and transgranular morphologyy. The main crack presents small branching and cleavage propagation with a clear influence of corrosion (hydrogen evoution) .
27
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Nital Etched Micrography by SEMDf - Corrosion Cracking
ML00163 — Corrosion Fatigue of a Boiler Waterwall TubeM - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Micrographic detail, by scanning electron microscopy, of the external tube surface, presenting the crack at the weld margin. The microstructure if ferritic in the left side (weld metal) and bainitic in the right side of the crack (heat affected zone).
90
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - Nital Etched Micrography by SEMDf - Cracking
Corrosion Fatigue of a Boiler Waterwall Tube
4
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - Nital Etched Micrography by SEMDf - Pearlite
ML00143 — Impact of a .308 Winchester on A36 PlateM - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Micrographic detail of the plate section, evidencing the non affected ferritic-pearlitic structure.
57
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by SEMDf - Ferrite and Pearlite
Micrography the ferritic-pearlitic structure close to the region where the projectile penetrate the plate.
21
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by SEMDf - Plastic Deformation
Micrographic detail of the ferritic-pearlitic structure close to the region where the projectile penetrate the plate.
19
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by SEMDf - Plastic Deformation
Micrography the ferritic-pearlitic structure close to the region where the projectile penetrate the plate.
17
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by SEMDf - Plastic Deformation
Micrographic detail of the ferritic-pearlitic structure close to the region where the projectile penetrate the plate.
9
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by SEMDf - Plastic Deformation

+2 more from this case →

ML00052 — Cold Cracks in API 5CT L80 Tube Welded to a Structural PartM - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Micrographic detail of the ferritic structure in the weld metal close to the low alloy steel tube, by scanning electron microscopy. The weld metal presents a typical aspect for high strenght weld metal (100% acicular ferrite).
32
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Weld Metal
Micrographic detail of the fusion line of the carbon steel plate, by scanning electron microscopy, showing the bainitic structure at the HAZ and ferritic structure in the weld metal.
34
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Fusion Line
Micrographic detail of the ferritic structure in the weld metal close to the carbon steel plate, by scanning electron microscopy. The weld metal presents a typical aspect for low strenght weld metal (grain boundary and primary ferrite, plus acicular ferrite).
30
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Weld Metal
Micrographic detail of the fusion line of the low alloy steel tube, by scanning electron microscopy, showing the martensitic structure at the HAZ and acicular ferritic structure in the weld metal.
29
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Fusion Line
Micrographic detail of the weld metal presenting 100% of acicular ferrite. Although the adopted filler metal was of a low strenght type, the dilution of the tube chemistry in the weld created a typically high strenght weld metal.
26
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Weld Metal

+1 more from this case →

ML00019 — Transgranular SCC in Boiler Steam DrumM - CMn SteelP - Rolled PlateAp - BoilerCd - Stress Corrosion
Micrographic detail of the transgranular stress corrosion cracking.
69
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 Crack