Optical Microscope

11 cases · 76 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Damage Microstructure: Martensite clear all

Optical Microscope — sub-branches

As polished micrography 6Micro by OM, picric acid+FeCl3+H2O etch 3Micrography by OM 2Nital Etched Micrography by OM 65

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Low magnification micrography presenting segregation bands in a martensitic structure. In the segregated regions the Nital etch effect is lower and the bands appear lighter. The black spots and lines are inclusions (some elongated) in the band.
91
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrography of the tooth gear, in a transverse section, close to surface. The material presents light ghost marks that reveal chemical segregations.
80
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Nital Etched Micrography by OMDf - At the Surface
Micrography of a transverse section of the spring, at the surface showing pits full of deposits.
36
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Transverse Section
Micrography of the thermal spray (TS) layer showing the different alloys, gray oxides and black voids. The Ni base TS alloy is of a yellow colour at the interface with the shaft substrate (in the left). The Cr base TS alloy appears white, similar to the shaft substrate. Longitudinal section of the shaft.
42
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - As polished micrographyDf - Coating Layer
Micrographic detail of the forging lap defect that appears at the nut surface like a crack, filled with oxides. The nut presented a martensitic structure in the center of the nut, but in the regions adjacent to the defect the structure is ferritic-bainitic due to decarburization. There are several globular oxides (grey spots) that became entrapped during the forging.
654
VIEW
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - Nital Etched Micrography by OMDf - Crack
Micrographic detail of the through wall cracking, slightly branched and thin.
656
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Cracking
The disc spring presented several small pits, as this one, that did not propagate.
24
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Pitting
Micrographic detail of a longitudinal section of the pin, at the fracture position, showing secondary cracks with intergranular and transgranular morphology.
59
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Brittle Cracks

More from these cases

ML00182 — Brittle Fracture of a LAS Fixing RodM - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Micrography presenting segregation bands (less etched) in a tempered martensitic microstructure.
81
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Segregated Regions
Micrography presenting a tempered martensitic microstructure, with light etch in segregated bands.
74
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Tempered Martensite
Low magnification micrography, revealing (in black) the impurities in the segregated bands.
63
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Micro by OM, picric acid+FeCl3+H2O etchDf - Longitudinal Section
Micrographic detail of the segregated bands.
61
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Micro by OM, picric acid+FeCl3+H2O etchDf - Segregated Regions
Micrographic etch for revealing previous austenite grain boundaries, that shows the impurities.
54
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Micro by OM, picric acid+FeCl3+H2O etchDf - Segregated Regions

+1 more from this case →

ML00181 — Wear of a Carburized Hypoid GearM - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Micrographic detail of the case hardened martensitic structure, close to the surface, with a microhardness level of about 600 Vickers (load 0.3kg).
70
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the tooth gear, in a transverse section of center region. Again, some segregation patterns are visible.
58
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrography of the core structure, in the center of layer, with a microhardness level of about 220 Vickers (load 0.3kg).
58
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Nital Etched Micrography by OMDf - Bainitic Martensitic
Micrographic detail of the fractured region transverse to the tooth. Secondary parallel cracks propagating in the tooth structure, tyypical of contact fatigue.
38
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Nital Etched Micrography by OMDf - Secondary Cracks
Wear of a Carburized Hypoid Gear
3
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Nital Etched Micrography by OMDf - Bainitic Martensitic
ML00172 — Brittle Fracture of a LAS Valve SpringM - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Micrographic detail of the transverse section of the spring, at the surface, showing the pits full of corrosion deposits.
31
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Surface Deposits
Micrographic detail of spring surface, showing the pits full of corrosion deposits and a small decarburized layer (probably from the manufacturing processes).
30
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Decarburized Surface
Micrography of a longitudinal section of the spring, at the surface, indicating that there are multiple intergranular cracks initiating from the pit.
26
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - As polished micrographyDf - Multiple cracks
Micrographic aspect of the multiple intergranular cracks, initiating from the bottom of a pit.
25
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - As polished micrographyDf - Intergranular Cracking
Micrographic detail of the intergranular cracks, initiating from the bottom of a pit.
29
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - As polished micrographyDf - Intergranular Cracking

+3 more from this case →

ML00108 — Thermal Spray Layer in a Pinion ShaftM - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Micrographic detail, as polished in a longitudinal section, of the interface between the shaft substrate and the thermal spray layer. In the left it is the shaft substrate also presenting parts of aligned inclusions (gray). In the center it is the Ni base TS alloy and in the right it is the Cr base TS alloy. There are also black voids and grey oxides.
33
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - As polished micrographyDf - Coating Layer
Micrography of the interface between the shaft surface and the thermal spray layer. The shaft steel presents a quenched and tempered structure. Longitudinal section.
32
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Coating Layer
Micrographic detail of the interface between the shaft surface and the thermal spray layer. The shaft steel presents a quenched and tempered structure. Longitudinal section.
33
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Coating Layer
Micrographic detail of the interface between the shaft surface and the thermal spray layer. The shaft steel presents a quenched and (over) tempered structure. Longitudinal section.
35
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Coating Layer
Shaft microstructure in the longitudinal section, showing aligned segregations typical of the material forming.
31
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Longitudinal Section

+4 more from this case →

ML00099 — Forging Defect in a Cadmium Plated NutM - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Micrography of the nut in a section transverse to the surface indication. There are several microcracks (parallel and perpendicular to the nut surface) filled with oxides. The nut presented a martensitic microstructure in the center of the thickness and a ferritic-bainitic microstructure at surface and adjacent to the defect, due to decarburization occurred during high temperature forging.
130
VIEW
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - Nital Etched Micrography by OMDf - Crack
Micrographic detail of the lap at the nut surface, as polished. The 20 microns cadmium layer is evident, penetrating in the lap.
46
VIEW
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - As polished micrographyDf - Lap
Tempered martensitic microstructure in the transverse section of the nut, in the center. The material presented 29 HRc that is typical of a quenched and tempered steel.
30
VIEW
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - Nital Etched Micrography by OMDf - Martensite
Ferritic-bainitic microstructure in the transverse section of the nut, at the surface where the cadmium plate is also evident. The nut surface presents a decarburized layer and the lap entrapped oxides.
30
VIEW
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - Nital Etched Micrography by OMDf - Bainitic Ferrite
ML00093 — MIC of a Drilling ToolM - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Micrography of a longitudinal section of the housing presenting a uniform tempered martensitic structure. The material presented a thickness about 2.5 mm in the region where the cracking started.
52
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Uniform Structure
Micrography of a longitudinal section of the housing presenting a uniform tempered martensitic structure.
51
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
A micrography of the housing in a transverse section showing a through wall cracking, slightly branched and thin. The internal surface of the housing appears in the bottom of the figure.
26
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Cracking
ML00080 — MIC of Stacking Disc SpringsM - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Micrographic aspect of the disc in the longitudinal section. Tempered martensitic structure, probably strain hardened.
30
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic aspect of the disc in the transverse section. Tempered martensitic structure, probably strain hardened.
31
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic aspect of the disc fracture (in the right side of the figure). It is possible to see that the structure is martensitic and there are secondary intergranular cracks associated to the fracture.
25
VIEW
ML00080 / Sep.2017
MIC of Stacking Disc Springs
M - Low Alloy Medium Carbon QTP - SpringAp - SubseaCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Intergranular Cracking
ML00009 — Hydrogen Cracking of a 5" Drill Pipe S135M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Micrography of the longitudinal section of the pin showing a tempered martensite structure, with bands that are associated to segregations. The pin presented average hardness of 38 HRc in the section.
63
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Banded Structure
Micrography of the longitudinal section of the pin showing a tempered martensite structure. The pin presented average hardness of 38 HRc in the section.
53
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic detail of the longitudinal section of the pin showing a tempered martensite structure. The pin presented average hardness of 38 HRc in the section.
55
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of a longitudinal section of the pin, at the fracture position, showing a low magnification aspect of the fracture surface (top of the figure) and secondary cracks associated to the segregation band.
51
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Cracking
Micrography of a longitudinal section of the pin, at the fracture position, showing the main fracture surface and secondary cracks associated to a segregation band, with an intergranular morphology.
49
VIEW
ML00009 / Sep.2017
Hydrogen Cracking of a 5" Drill Pipe S135
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Intergranular Cracking

+1 more from this case →