Optical Microscope

11 cases · 124 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Microstructure: Bainite clear all

Optical Microscope — sub-branches

As polished micrography 9Chromic Acid Electrolytic Etched 6Micro by OM, picric acid+FeCl3+H2O etch 1Micrography by OM 2Nital Etched Micrography by OM 97Oxalic Acid Electrolytic Etch 9

Results

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The tube microstructure is ferritic-pearlitic, typical of this kind of material. No evidences of microstrutural changes were detected (no overheating, no decarburization).
177
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Image by scanning electron microscopy of the metallurgically bonded interface of the internally cladded pipe. It is a longitudinal seam welded pipe, with substrate in low alloy steel X65 and clad plate in Alloy 625 (welded by a solid state process). The region is a detail in the side of the Ni alloy clad plate where a grain refinement has occurred probably due to recrystallization of a strain hardened region during later heat treatment. The microhardness of this region is a lot higher than the value obtained out of this region, in the clad plate.
904
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Oxalic Acid Electrolytic EtchDf - Clad Interface
Micrography of a longitudinal section of the pipe substrate, in low magnification, showing a uniform microstructure,
79
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
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 longitudinal section of the tube, close to the external surface. The carburizing layer consists of a bainitic structure, with intergranular and intragranular carbide precipitation.
1184
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - Nital Etched Micrography by OMDf - Carburized Layer
Micrography of the 4130 steel, normalized and tempered. The structure is sligthly banded (segregated) and the average hardness level is 20 HRc.
92
VIEW
ML00102 / May.2018
AISI 4130 Forging Welded and Overlaid
M - Low Alloy SteelP - CladdingAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of a longitudinal section of the pin, in the center. The low carbon content of the steel in the center of the pin makes the structure bainitic even though it was quenched and tempered after carburizing.
80
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrography of the welded joint fusion line presenting the liquation cracking. The weld metal is in the right side (bottom) and the forged connector heat affected zone is in the left side (top).
83
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracking

More from these cases

ML00163 — Corrosion Fatigue of a Boiler Waterwall TubeM - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
The internal side of the tube presented multiple cracks, filled with oxides, blunt-tipped, typical of a corrosion fatigue cracking mechanism.
160
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - As polished micrographyDf - Parallel cracks
Micrographic detail of the corrosion cracking from internal side of the tube, in several points at the tube surface.
156
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - As polished micrographyDf - Corrosion Cracking
Low magnification micrography of the multiple cracks, parallel, transgranular. No evidences of microstrutural changes (heat evolution or decarburization).
127
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Transgranular Cracking
Micrography presenting the internal tube surface with several parallel cracks, some still in the beginning (less than 0.1 mm deep).
115
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Parallel cracks
Micrography of the crack tip, initiated from the internal tube surface. The crack is transgranular, filled with oxides and blunt-tipped.
109
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Transgranular Cracking

+9 more from this case →

ML00133 — Seam Welded Pipe Cladded with Alloy 625M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Micrography of a longitudinal section of the pipe substrate, in low magnification, showing a uniform microstructure,
51
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure obtained by the pipe quenching and tempering,
48
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrographic detail of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure,
50
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the pipe at the interface with the clad plate, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
54
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrography of a longitudinal section of the pipe at the interface with the clad plate, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
51
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface

+10 more from this case →

ML00132 — Seamless Pipe Overlaid with Alloy 625M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Micrography of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure obtained by the pipe quenching and tempering,
72
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrographic detail of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure.
68
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the pipe at the overlay fusion line, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
66
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrography of a longitudinal section of the pipe at the overlay fusion line, with Nital etch that reveals only the low alloy steel structure, to the left side of the image. Some decarburization of the low alloy steel substrate is evident since the microstructure is slightly different a little far from the interface.
66
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrographic detail of a longitudinal section of the pipe at the interface with the clad plate, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
59
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface

+7 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 →

ML00107 — Carburized 9Cr1MoV Superheater TubeM - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Micrography of the longitudinal section of the tube, close to the internal surface. A thick scale is evident, but no microstructural changes compared to the center of the tube.
183
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the tube in the center of the thickness, showing a ferritic-bainitic structure of this CrMoV steel.
156
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the tube in the center of the thickness, showing a ferritic-bainitic structure of this CrMoV steel.
137
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the tube in the center of the thickness, showing a ferritic-bainitic structure of this CrMoV steel.
142
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of the longitudinal section of the tube, close to the external surface, presenting a thick deposit.
109
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - As polished micrographyDf - Close to the External Surface

+7 more from this case →

ML00102 — AISI 4130 Forging Welded and OverlaidM - Low Alloy SteelP - CladdingAp - Oil and GasCd - Welding
Micrography of the 4130 steel, normalized and tempered. The microstructure is bainitic.
88
VIEW
ML00102 / May.2018
AISI 4130 Forging Welded and Overlaid
M - Low Alloy SteelP - CladdingAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrographic detail of the bainitic structure of the 4130 steel, normalized and tempered.
87
VIEW
ML00102 / May.2018
AISI 4130 Forging Welded and Overlaid
M - Low Alloy SteelP - CladdingAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of the tubular 4130 forging at the heat affected zone (HAZ) of the Inconel overlay (white because it was not etched with the Nital). The structure is ferritic/bainitic because the overlay was conducted in two layers, and all the HAZ was reheated during welding.
66
VIEW
ML00102 / May.2018
AISI 4130 Forging Welded and Overlaid
M - Low Alloy SteelP - CladdingAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Micrography of the tubular 4130 forging at the heat affected zone (HAZ) of the Inconel overlay (white because it was not etched with the Nital). The structure is ferritic/bainitic because the overlay was conducted in two layers, and all the HAZ was reheated during welding.
61
VIEW
ML00102 / May.2018
AISI 4130 Forging Welded and Overlaid
M - Low Alloy SteelP - CladdingAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Micrographic detail of the bainitic heat affected zone (HAZ) of 4130 forging at the Inconel overlay.
50
VIEW
ML00102 / May.2018
AISI 4130 Forging Welded and Overlaid
M - Low Alloy SteelP - CladdingAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Bainitic Ferrite

+6 more from this case →

ML00081 — Hydrogen Cracking of a Chromium Plated Carburized PinM - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Micrographic detail of the bainitic structure in the center of the pin, that was quenched and tempered after carburizing.
75
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the pin, at the surface. The pin was carburized, quenched and tempered (yellow diffuse layer at the surface, 0.5 mm of extension) and a white layer of hard chromium plating is evident.
108
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Carburized Layer
Micrographic detail a longitudinal section of the pin, at the surface, showing the case hardened. The pin carburized, quenched and tempered structure presents a gradient of carbon content and consequently a gradient of martensitic structure and hardness. Close to the surface the hardness level is 742 HV1 .
86
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - At the Surface
Micrographic detail of the high hardness martensitic structure at the surface of the pin, that was quenched and tempered after carburizing.
66
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography that presents a secondary cracking (adjacent to the broken surface) propagating 500 microns from the surface, where there is a white layer of hard chromium .
78
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Carburized Layer

+3 more from this case →

ML00072 — Liquation Cracks in a High Strength JointM - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
The liquation crack is a hot crack in the base metal (at the HAZ) that induces a solidification crack in the weld metal.
66
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrographic detail of the cracks at the fusion line of the welded joint, at the connector side. The cracking presents morphology of melting regions of impurities at grain boundaries of the large grains of the heat affected zone (HAZ).
57
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Fusion Line
The HAZ presents microcracks at previous austenite grain boundaries. These regions melted during welding and generated cracks associated to low melting temperature phases.
48
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Microcracks
The HAZ presents microcracks at previous austenite grain boundaries. These regions melted during welding and generated cracks associated to low melting temperature phases.
43
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Microcracks
Micrography of the AISI 4130 forging, 5/8" thickness, close to the welded region, in the longitudinal section.
42
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal Left Side

+7 more from this case →