Optical Microscope

114 cases · 480 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Detail focus: Damage clear all

Optical Microscope — sub-branches

As polished micrography 69Eletrolytically Etched Micrography by OM 1FeCl3+HCl+Ethanol Etched Micro 6FeCl3+HCl+H2O Etched Micro 4H2SO4+HNO3+H3PO4 Etched Micro 1Kalling Etched Micrography by OM 63Keller Etched Micrography by OM 16Kroll Etched Micrography by OM 5Micro by OM, HCl + Ethanol + Picric Acid 2Micro by OM, picric acid+FeCl3+H2O etch 3Micrography by OM 43Micrography by OM using A262 Method A 24Micrography by OM, HF + HNO3 + H2O etch 2NaOH Electrolytic Etched Micro 13Nital Etched Micrography by OM 212Oxalic Acid Electrolytic Etch 16

Results

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Micrography of the plate section, close to the surface that suffered the impact. The projectile melted and created a film at the surface. HF+HNO3+H2O chemical etch.
13
VIEW
ML00144 / Aug.2018
Impact of a .380 Winchester on Ti64 Plate
M - Ti6Al4VP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - Micrography by OMDf - Melted film
Micrography of a longitudinal section, at the damage surface of the pin, where the thermal spray layer was partially detached and broken. The through layer breaking is ductile, typical of an overloading condition caused by the localized bending of the pin.
109
VIEW
ML00146 / Jul.2018
Plastic Deformation of a SDSS Riser Pin
M - Super Duplex Stainless SteelP - PinAp - O&G Well DrillingCd - Bending
Cm - NaOH Electrolytic Etched MicroDf - Layer Detachment
Micrographic detail of the plate section, as polished, close to the surface that suffered the impact. The copper alloy melted and created a yellow-orange deposit.
25
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - As polished micrographyDf - Melted film
Micrographic detail of the corroded surface of the cast cylinder, with interconnected graphites and a notch effect.
30
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - As polished micrographyDf - Corrosion
Micrography of the pipe in the leakage area, showing the preferential corrosion in the center of the autogenous weld and oxides inside the crevice, that appearas as a cracking but that is only a localized anodic process.
66
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 OMDf - Localized Corrosion
Micrography of a longitudinal section of the bolt, in a position close to the fracture (top) and bolt surface (left ), presenting several secondary intergranular cracks.
57
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - As polished micrographyDf - Intergranular Cracking
Micrography of the section transverse to the fracture (top of the figure). The fracture is intergranular, there are several secondary cracks, and there are deposits of zinc over the fracture. The zinc makes difficult the etch with Nital to reveal the microstructure close to the fracture surface.
67
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - Nital Etched Micrography by OMDf - Fracture
Micrography of a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
72
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - As polished micrographyDf - Intergranular Cracking

More from these cases

ML00144 — Impact of a .380 Winchester on Ti64 PlateM - Ti6Al4VP - Rolled PlateAp - StructureCd - Non-Pierced
Micrography of the damaged plate at the side of the bullet impact, top of the figure. The projectile sheared the plate but did not perforate it, and the projectile materials (Cu and Pb) deposited at the .surface. HF+HNO3+H2O chemical etch.
9
VIEW
ML00144 / Aug.2018
Impact of a .380 Winchester on Ti64 Plate
M - Ti6Al4VP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - Micrography by OMDf - Ductile Crack
Micrography of the damaged plate at the side of the bullet impact, top of the figure. The projectile, impacted in the right side of the crack, sheared the plate but did not perforate it and created several longitudinal ductile secondary cracks. HF+HNO3+H2O chemical etch.
16
VIEW
ML00144 / Aug.2018
Impact of a .380 Winchester on Ti64 Plate
M - Ti6Al4VP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - Micrography by OMDf - Ductile Crack
Micrographic detail of the damaged plate (the side of the bullet impact is to the top of the figure). The projectile, in the right side, sheared the plate but did not perforate it and created longitudinal ductile secondary cracks in the middle of the thickness. HF+HNO3+H2O chemical etch.
11
VIEW
ML00144 / Aug.2018
Impact of a .380 Winchester on Ti64 Plate
M - Ti6Al4VP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - Micrography by OMDf - Secondary Cracks
Micrographic detail of the shearing of the material due to the projectile impact. It is a very localized effect. HF+HNO3+H2O chemical etch.
13
VIEW
ML00144 / Aug.2018
Impact of a .380 Winchester on Ti64 Plate
M - Ti6Al4VP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - Micrography by OMDf - Ductile Crack
Micrography of the 3/8" thickness titanium alloy plate, in a section. The impact side of the plate is to the top of the figure. The plate was sheared through wall in a very localized position. HF+HNO3+H2O chemical etch.
6
VIEW
ML00144 / Aug.2018
Impact of a .380 Winchester on Ti64 Plate
M - Ti6Al4VP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - Micrography by OMDf - Ductile Crack

+6 more from this case →

ML00146 — Plastic Deformation of a SDSS Riser PinM - Super Duplex Stainless SteelP - PinAp - O&G Well DrillingCd - Bending
Micrographic detail of the damage surface layer, detached and broken. The substrate is not affected and the rupture of the layer is typically by overloading.
117
VIEW
ML00146 / Jul.2018
Plastic Deformation of a SDSS Riser Pin
M - Super Duplex Stainless SteelP - PinAp - O&G Well DrillingCd - Bending
Cm - NaOH Electrolytic Etched MicroDf - Layer Detachment
ML00143 — Impact of a .308 Winchester on A36 PlateM - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Micrographic detail of the plate section, as polished, close to the surface that suffered the impact. The copper alloy melted and created a yellow-orange deposit.
26
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - As polished micrographyDf - Melted film
Micrography of the plate section, close to the surface that suffered the impact. The copper alloy melted and created a yellow-orange deposit. The plate material presented a strong plastic deformation, aligning the grains and strain hardening the microstructure.
26
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 OMDf - Plastic Deformation
Micrographic detail of the copper alloy melted and adhered at the surface and a strong plastic deformation of the plate microstructure.
28
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 OMDf - Plastic Deformation
Micrography of the damaged plate at the side of the bullet impact, top of the figure. The perforated hole expulsed the material to the top and bottom directions and the copper alloy is evident at the hole surface.After etching it is clear the strong plastic deformation of the plate microstructure.
26
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 OMDf - Plastic Deformation
Micrographic detail of the damaged plate at the side of the bullet impact. The perforated hole expulsed the material to the top and bottom directions and the copper alloy is evident at the hole surface. There is a strong plastic deformation of the ferritic-pearlitic microstructure and the hardness level increased from 151 HV to 308 HV (1kg).
20
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 OMDf - Plastic Deformation

+11 more from this case →

ML00141 — Brittle Fracture of a Corroded Gray Cast IronM - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Micrographic detail of the corroded surface of the cast cylinder in contact with treated water, as polished, showing that the corrosion occurs preferentially at the flake to matrix interfaces.
31
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - As polished micrographyDf - Corrosion
Same position of the previous micrographic detail, at the internal surface of the cast cylinder in contact with treated water, after Nital etching, showing the corrosion at the flake to matrix interfaces.
30
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 OMDf - Corrosion
ML00140 — Preferential Corrosion of Pipe Seam WeldM - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Micrographic detail of the autogenous seam weld. The localized dissolution occurrs exactly at the weld metal that presents a bainitic structure of average hardness about 230HV, compared to the heat affected zone presenting average of 202 HV and the base metal presenting average of 180HV.
57
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 OMDf - Localized Corrosion
Micrographic detail presenting the slighltly decarburized ferritic structure, with inclusions, in the center of the weld, surrounded by a bainitic structure and the preferential corrosion in the weld.
51
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 OMDf - Localized Corrosion
Micrography of the pipe in the leakage area, at the internal pipe surface, showing the preferential corrosion in the center of the autogenous weld and oxides inside the crevice. The morphology of the corrosion is similar to a cracking but the analysis show that it is a localized anodic process.
45
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 OMDf - Preferential Dissolution
Micrography of the pipe at the leakage position showing an oxide layer inside the crevice. The corrosion occurred exactly at the weld metal and the region at the margin of the damage shows the heat affected zone of the autogenous weld, with a refined grain size.
41
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 OMDf - Preferential Dissolution
Micrography of the internal pipe surface at the leakage position showing an oxide layer inside the crevice. The corrosion occurred exactly at the weld metal and the region at the margin of the damage shows the heat affected zone of the autogenous weld, with a refined grain size.
40
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 OMDf - Preferential Dissolution

+1 more from this case →

ML00139 — Hydrogen Fracture of a 17-4 PH Allen BoltM - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Micrographic detail of the secondary intergranular cracks close to the surface of the bolt, where the fracture occurred.
56
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - As polished micrographyDf - Intergranular Cracking
Micrography of a longitudinal section of the bolt, close to the fracture surface (top of the figure). The fracture is macroscopically flat and started at the surface (left side) in a position close to the bolt body to bolt head transition. The structure is aged martensite.
55
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Brittle Fracture
Micrography of a longitudinal section of the bolt, in a position close to the fracture (top) and bolt surface (left ), presenting several secondary intergranular cracks. The structure is aged martensite and the cracks are located in the previous austenite grain boundaries.
52
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Fracture
Micrographic detail of the secondary intergranular cracks (in the previous austenite grain boundaries).
49
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Secondary Cracks
Micrographic detail of the secondary intergranular cracks (in the previous austenite grain boundaries).
48
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Secondary Cracks

+7 more from this case →

ML00138 — Liquid Metal Embrittlement of a HSLA SteelM - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Micrography of the cracking parallel to the fracture, as polished. The fracture is branched, there are several secondary cracks, with a clear intergranular morphology.
65
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - As polished micrographyDf - Cracking
Micrographic detail of the branch cracking parallel to the fracture, as polished, showing that the cracks are filled with zinc.
62
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - As polished micrographyDf - Secondary Cracks
Micrography of the branch cracking parallel to the fracture. There are several secondary intergranular cracks and the cracks are filled with zinc. The zinc appears dark because of the Nital etch, and the steel is not fully revealed because of the protection by the zinc.
54
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - Nital Etched Micrography by OMDf - Cracking
Micrographic detail of the secondary intergranular cracks, filled with zinc. The zinc appears dark because of the Nital etch, and the steel is not fully revealed because of the protection by the zinc.
48
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - Nital Etched Micrography by OMDf - Secondary Cracks
Micrography of the branch cracking parallel to the fracture. There are several secondary intergranular cracks and the cracks are filled with zinc. The zinc appears dark because of the Nital etch, and the steel close to the cracking is not fully revealed because of the protection by the zinc.
41
VIEW
ML00138 / Jun.2018
Liquid Metal Embrittlement of a HSLA Steel
M - High Strength Low AlloyP - Coated ProductAp - Mechanical IndustryCd - Liquid Metal Embrittlement
Cm - Nital Etched Micrography by OMDf - Cracks

+4 more from this case →

ML00137 — Brittle Fracture of a 15-5 PH Valve SpringM - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Micrographic detail of a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
65
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - As polished micrographyDf - Intergranular Cracking
Micrographic detail of a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
60
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Intergranular Cracking
Micrography of a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
57
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Intergranular Cracking
Micrographic detail of a longitudinal section of the spring indicating that under the deposits there are intergranular cracks initiating at the spring surface.
57
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Intergranular Cracking
Micrography of a section transverse to the fracture, in the starting point, showing the intergranular morphology of the fracture surface.
38
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Kalling Etched Micrography by OMDf - Intergranular Fracture

+6 more from this case →