Optical Microscope

4 cases · 11 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Application: Ship Condition: Brittle Behavior Detail focus: Microstructure clear all

Optical Microscope — sub-branches

Nital Etched Micrography by OM 11

Results

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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 the longitudinal section of the cylinder, at the internal diameter, in contact with the treated cooling water, presenting large graphite flakes in a predominatly perlitic matrix. It is important to mention that the flakes are almost interconnecting themelves.
47
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 - Graphite in Flakes
Micrographic detail of the longitudinal section of the fitiing, in a free-cutting steel. The microstructure is predominantly ferritic, with small perlitic areas and some free cementite at ferritic grain boundaries. There is a large amount of sulfide inclusions, aligned perpendicular to the forming direction.
106
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Non Metallic Inclusions
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

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 wire, martensitic.
24
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 - Martensite
Micrographic detail of the martensitic structure, uniform through thickness.
17
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 - Martensite
ML00141 — Brittle Fracture of a Corroded Gray Cast IronM - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Micrography of the longitudinal section of the cylinder, at the internal diameter, in contact with the treated cooling water, presenting large graphite flakes in a predominatly perlitic matrix. It is important to mention that the flakes are almost interconnecting themelves.
48
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 - Predominantly Pearlitic
Micrography of the longitudinal section of the cylinder, in the center of the thickness, presenting large graphite flakes in a predominatly perlitic matrix. There are also ferritic regions.
33
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 - Graphite in Flakes
Micrography of the longitudinal section of the cylinder, in the center of the thickness, presenting large graphite flakes in a predominatly pearlitic matrix.
31
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 - Predominantly Pearlitic
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. It is also possible to see free carbides (cementite) very close to the cylinder surface (less than 50 microns), associated to positions of graphite. This surface was painted.
25
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 - Ferrite and Pearlite
ML00103 — Brittle Fracture of a Free-Cutting ConnectorM - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Micrographic detail of the transverse section of the fitiing, in a free-cutting steel. The microstructure is predominantly ferritic, some perlitic areas and free cementite at ferritic grain boundaries. There is a large amount of inclusions, that appear as spots.
82
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Predominantly Ferritic