Microstructure

24 cases · 80 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Standard: AISI Capture method: Nital Etched Micrography by OM clear all

Microstructure — sub-branches

Acicular Ferrite 1Bainite 6Bainitic Ferrite 3Banded Structure 7Carburized Layer 2Clad Interface 2Coarse Structure 4Coating Layer 3Decarburized Surface 1Ferrite 3Ferrite and Pearlite 6Fusion Line 2Martensite 29Pearlite 4Predominantly Ferritic 1Strain Hardened 3Tempered Martensite 1Uniform Structure 2

Results

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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
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
Metallographic detail of the longitudinal section of the clamp with a ferritic pearlitic structure.
32
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Low magnification micrography of a longitudinal section of the valve body, in the center of the thickness. As expected for this high strength steel, the microstructure is martensitic, but with segregation bands.
48
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Banded Structure
Tempered martensite of the pipe body of this API 5D grade S135 drill pipe. The material presents, at this low magnification micrographic aspect, a slightly banded structure, usual for this type of drill pipe.
58
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Banded Structure
Micrography of the wheel in the center of the thickness, presenting a predominantly pearlitic structure and average hardness abot 196HB.
74
VIEW
ML00158 / Feb.2020
Surface Hardened Carbon Steel Wheel
M - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Coarse Structure
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
The coarse structure in the center of the shaft thickness is evidenced by free ferrite islands at the previous austenite grains. The presence of a pearlitic structure evidences the slow cool of the material.
85
VIEW
ML00152 / Dec.2018
Low Alloy Steel Pump Shaft
M - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Coarse Structure

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
ML00171 — Corrosion Fatigue of U Bolt Pipe ClampM - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Metallographic detail of the ferritic perlitic structure.
31
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
ML00162 — Valve Body Crack Growth from Weld DefectsM - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Micrography of a longitudinal section of the valve body presenting a martensitic microstructure. The structure is banded and the darker regions show inclusions (grey sulfides).
50
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic detail of the martensitic microstructure, in the longitudinal section. The hardness of the valve body is 34 HRc (Rockwell C) all through the thickness.
47
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the weld repair at the fusion line. Weld metal to the right and heat affected zone to the left.
37
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Fusion Line
Micrographic detail of the fusion line.
33
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Fusion Line
ML00159 — Collapse of a Drill PipeM - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Micrographic detail of the tempered martensite in the longitudinal section of the pipe body. Uniform structure.
45
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic detail of the tempered martensite in the longitudinal section of the pipe body.
39
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic detail of sheared pipe, showing strong plastic deformation at the fracture. The structure shows the shear effect at the fracture.
16
VIEW
ML00159 / Mar.2020
Collapse of a Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Ductile Behavior
Cm - Nital Etched Micrography by OMDf - Martensite
ML00158 — Surface Hardened Carbon Steel WheelM - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Micrographic detail of the coarse pearlitic structure in the center of the wheel thickness. The part presents a wrought structure.
73
VIEW
ML00158 / Feb.2020
Surface Hardened Carbon Steel Wheel
M - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Pearlite
Micrographic detail of the tempered martensitic structure.
50
VIEW
ML00158 / Feb.2020
Surface Hardened Carbon Steel Wheel
M - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic aspect of the pearlitic structure at the surface not heat treated, showing a lower grain size than in the center of the thickness.
35
VIEW
ML00158 / Feb.2020
Surface Hardened Carbon Steel Wheel
M - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Pearlite
Micrographic detail of the pearlitic microstructure in a region where the structure is not so coarse than in the center of the thickness.
30
VIEW
ML00158 / Feb.2020
Surface Hardened Carbon Steel Wheel
M - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Pearlite
ML00152 — Low Alloy Steel Pump ShaftM - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
The longitudinal section of the shaft, at the surface, presenting only a small refining in the previous austenite grain boundaries than in the center, indicating that the material was slowed colled from forming and not heat treated.
67
VIEW
ML00152 / Dec.2018
Low Alloy Steel Pump Shaft
M - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Coarse Structure
Micrographic detail of the pearlitic structure at the surface of the shaft thickness.
69
VIEW
ML00152 / Dec.2018
Low Alloy Steel Pump Shaft
M - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Pearlite