Nital Etched Micrography by OM

12 cases · 90 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Application: Oil and Gas Condition: Damage clear all

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Micrography of the thread at the valve body surface, showing localized dissolution of the thread.
73
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Corroded Thread
Low magnification micrography of a strain hardened pearlitic structure, in a longitudinal section, of one 3.2mm round wire of one strand.
62
VIEW
ML00175 / Aug.2021
Localized External Wear of a Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
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 a longitudinal section of the socket at the position where the fracture occurred. Uniform tempered martensitic structure. The hardness of this microstructure is 639 HV1Kg.
74
VIEW
ML00161 / Mar.2020
Brittle Fracture of a High Strength Socket
M - Medium Carbon Tool SteelP - ToolAp - Oil and GasCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography, by optical microscope, of the longitudinal section of a damaged bolt, in the center of the thickness. The microstructure is austenitic, free from carbides, strain hardened. The hardness values of the material are from 200HV1 to 300HV1, that meets the class 2 of strenght (ASTM A193 B8M class 2).
79
VIEW
ML00157 / Feb.2020
Bolts Under Chloride SCC Conditions
M - Austenitic Stainless SteelP - BoltAp - Oil and GasCd - Stress Corrosion
Cm - Nital Etched Micrography by OMDf - Strain Hardened
Micrography of the longitudinal section of the stud presenting a tempered martensite structure, slightly banded. Hardness 45 HRc.
33
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
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
Micrography of a transverse section of the lifting part, showing interdendritic voids close to the surface at the inner diameter of the padeye. The microstructure is tempered martensite.
450
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Casting defects

More from these cases

ML00184 — Dissimilar Steels in a Threaded ConnectionM - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Micrography of the valve body carbon steel thread, in the valley. Ferritic-bainitic structure.
77
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Transverse Section
Micrographic detail of the valve body carbon steel thread, in the valley. Ferritic-bainitic structure.
69
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Bainitic Ferrite
Micrography of the valve body carbon steel thread, in the peak. Ferritic-bainitic structure.
64
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Corroded Thread
Micrographic detail of the valve body carbon steel thread, in the peak. Ferritic-bainitic structure.
55
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Corroded Thread
Cross-section near a threaded surface showing an acicular matrix structure bordered by a dark, layered corrosion/oxide band along the thread root.
1
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Nital Etched Micrography by OMDf - Oxide Layer
ML00175 — Localized External Wear of a Wire RopeM - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Highly strain hardened pearlitic structure of one external wire, 3.2mm diameter, of one strand.
55
VIEW
ML00175 / Aug.2021
Localized External Wear of a Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Cm - Nital Etched Micrography by OMDf - Pearlite
Micrographic detail of the strain hardened pearlitic structure, in a longitudinal section, of a 3.2mm external round wire of one strand. This structure presented a hardness level about 500 HV (1kg), measured in the center of the thickness in the metallographic section.
47
VIEW
ML00175 / Aug.2021
Localized External Wear of a Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Cm - Nital Etched Micrography by OMDf - Strain Hardened
Metallographic aspect of the wire surface in one strand external wire, showing the presence of oxides.
42
VIEW
ML00175 / Aug.2021
Localized External Wear of a Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Cm - Nital Etched Micrography by OMDf - At the Surface
Metallographic detail of the wire surface in one strand external wire, showing the presence of oxides.
39
VIEW
ML00175 / Aug.2021
Localized External Wear of a Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Cm - Nital Etched Micrography by OMDf - Oxide Layer
Low magnification micrography of a strain hardened pearlitic structure, in a longitudinal section, of the 1.6mm round wire in the core.
34
VIEW
ML00175 / Aug.2021
Localized External Wear of a Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Cm - Nital Etched Micrography by OMDf - Longitudinal Section

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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 the transverse section of the spring wire, in the center, presenting a refined structure and segregation bands that are detected only in low magnification.
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 - Transverse Section
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
ML00161 — Brittle Fracture of a High Strength SocketM - Medium Carbon Tool SteelP - ToolAp - Oil and GasCd - Brittle Fracture
Micrography of a longitudinal section presenting an uniform tempered martensitic structure.
81
VIEW
ML00161 / Mar.2020
Brittle Fracture of a High Strength Socket
M - Medium Carbon Tool SteelP - ToolAp - Oil and GasCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic detail of the tempered martensitic structure.
80
VIEW
ML00161 / Mar.2020
Brittle Fracture of a High Strength Socket
M - Medium Carbon Tool SteelP - ToolAp - Oil and GasCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the socket in a section transverse to the fracture, showing the fracture in the top and some secondary brittle cracks.
42
VIEW
ML00161 / Mar.2020
Brittle Fracture of a High Strength Socket
M - Medium Carbon Tool SteelP - ToolAp - Oil and GasCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Secondary Cracks
Micrographic detail of a secondary crack transverse to the fracture (in the top), showing its appearance as multiple openings, straight and with intergranular and transgranular characteristics .
35
VIEW
ML00161 / Mar.2020
Brittle Fracture of a High Strength Socket
M - Medium Carbon Tool SteelP - ToolAp - Oil and GasCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Brittle Cracks
Micrographic detail of a secondary crack transverse to the fracture (in the top), showing its transgranular appearance at this position.
34
VIEW
ML00161 / Mar.2020
Brittle Fracture of a High Strength Socket
M - Medium Carbon Tool SteelP - ToolAp - Oil and GasCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Brittle Cracks

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ML00127 — Hydrogen Cracks of Cadmium Plated StudsM - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Micrography of the longitudinal section of the stud presenting a tempered martensite structure in the center of the thickness.
33
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
Low magnification micrographic image of the stud thread, in the longitudinal section, showing the segregation lines of the steel cut at the thread indicating it was machined.
30
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Machined Thread
Micrographic detail of the stud at the thread bottom.
27
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Machined Thread
Micrographic detail of the thread top, showing that the thread was machined.
29
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Machined Thread
Micrography of the longitudinal section of the stud showing a crack from the thread fillet, of a ductile aspect, opened during torque.
30
VIEW
ML00127 / May.2018
Hydrogen Cracks of Cadmium Plated Studs
M - Low Alloy Medium Carbon QTP - Allen StudAp - Oil and GasCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Fracture

+3 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
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
ML00098 — Brittle Fracture of a Casting Lifting DeviceM - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Micrography of the lifting padeye showing a dendritic path of a quenched and tempered martensitic microstructure. The segregated regions (white interdendritic regions) are more clearly identified in low magnification. Voids are located in these segregated regions.
21
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the lifting padeye showing a quenched and tempered martensitic microstructure. Voids are located in interdendritic segregated regions.
20
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the lifting padeye showing a quenched and tempered martensitic microstructure. Voids are located in interdendritic segregated regions. At this magnification the segregation is not clear.
16
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the lifting padeye showing a quenched and tempered martensitic microstructure. The hardness level of the material is about 39 HRc.
14
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the secondary crack, paralel to fracture, starting from the internal diameter of the padeye. The crack propagates in an interdendritic morphology, interconnecting casting defects.
13
VIEW
ML00098 / Nov.2017
Brittle Fracture of a Casting Lifting Device
M - Low Alloy Medium Carbon QTP - CastingAp - LiftingCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Secondary Cracks

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