Optical Microscope

13 cases · 39 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Damage Standard: AISI Detail focus: Sampling and Analysis clear all

Optical Microscope — sub-branches

As polished micrography 7Micro by OM, picric acid+FeCl3+H2O etch 1NaOH Electrolytic Etched Micro 2Nital Etched Micrography by OM 18Oxalic Acid Electrolytic Etch 11

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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
Sample surface. Microstructure of the plate base metal, exposed to high temperature exhausting gases. Refined austenite and some cracks.
24
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Oxalic Acid Electrolytic EtchDf - Base Metal
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
Metallographic image of a longitudinal section of the clamp (axis in the vertical direction), showing a refined ferritic perlitic structure.
34
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 - Longitudinal Section
The stub end was manufactured from a plate and the microstructure in a longitudial section shows a refined granular austenitic structure.
62
VIEW
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Longitudinal Section
Micrography of a longitudinal section of the tubing showing a granular structure, austenitic.
52
VIEW
ML00167 / Aug.2020
Fatigue of a Flared Tubing Connection
M - Austenitic Stainless SteelP - TubingAp - EngineCd - Mechanical Fatigue
Cm - Oxalic Acid Electrolytic EtchDf - Longitudinal Section
SAMPLE 1 AT THE FRACTURE - Micrography in low magnification where the thickness is reduced to zero (fracture). Side A (process side) to the bottom and side B (furnace environment side) to the top.
85
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - Oxalic Acid Electrolytic EtchDf - Low Mag
Low magnification micrography at the weld repair close to the internal surface of the valve body, in a longitudinal section. Weld metal to the bottom and heat affected zone to the top.
42
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 - Weld Repair

More from these cases

ML00182 — Brittle Fracture of a LAS Fixing RodM - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
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
ML00174 — Carburization of a 347 SS Welded JointM - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Sample surface. Microstructure of the weld metal, exposed to high temperature exhausting gases. Austeno-ferritic structure and some cracks.
20
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Oxalic Acid Electrolytic EtchDf - Weld Metal
Sample surface. Microstructure of the heat affected zone (weld metal to the left side and base metal to the right side), exposed to high temperature exhausting gases. Large austenitic grain size and cracks fully opened and filled with oxides.
24
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Oxalic Acid Electrolytic EtchDf - Heat Affected Zone
ML00172 — Brittle Fracture of a LAS Valve SpringM - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
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
ML00171 — Corrosion Fatigue of U Bolt Pipe ClampM - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
The clamp presented several cracks, parallel, transverse to the axis. The appearance of the cracks in the metallographic section shows that some cracks propagate and growth with a irregular path.
24
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 - Longitudinal Section
ML00168 — SCC of Austenitic SS Flange Stub EndM - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Micrography of the stub end, external side to the top, presenting multiple cracks propagating throught wall.
48
VIEW
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - As polished micrographyDf - Close to the External Surface
Micrography of the stub end close to the external surface, outer diameter in the top of the image, presenting multiple cracks starting fro the surface and propagating into the thickness, through wall.
32
VIEW
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Close to the External Surface
Micrography of the stub end in the middle of the thickness, outer diameter to the top of the image, presenting multiple branched cracks.
27
VIEW
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - In the Center of the Thickness
ML00167 — Fatigue of a Flared Tubing ConnectionM - Austenitic Stainless SteelP - TubingAp - EngineCd - Mechanical Fatigue
Micrography of a longitudinal section of the tubing where the fracture occurred. the left side is the outer diameter and the right side is the inner diameter.
37
VIEW
ML00167 / Aug.2020
Fatigue of a Flared Tubing Connection
M - Austenitic Stainless SteelP - TubingAp - EngineCd - Mechanical Fatigue
Cm - Oxalic Acid Electrolytic EtchDf - At the Surface
ML00160 — High Temperature Degradation of 310SSM - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
SAMPLE 1 AT 1 mm THICKNESS - Micrography in low magnification in the center of the thickness. The microstructure is austenitic with secondary intergranular and intragranular precipitation.
77
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - Oxalic Acid Electrolytic EtchDf - Low Mag
SAMPLE 2 AT 2 mm THICKNESS - Micrography in low magnification in the center of the thickness. The microstructure is austenitic with secondary intergranular and intragranular precipitation. No variation in the microstructure of the center of the plate, compared to sample 1.
52
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - Oxalic Acid Electrolytic EtchDf - Low Mag
SAMPLE 3 AT 4 mm THICKNESS - Micrography in low magnification in the center of the thickness. The microstructure is austenitic with secondary intergranular and intragranular precipitation, but this micrography was obtained in the longitudinal section, presenting the plate alignment and was etched with NaOH, adopted to colour the sigma phase .
40
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - NaOH Electrolytic Etched MicroDf - Low Mag
SAMPLE 1 AT 1 mm THICKNESS - Micrography in low magnification in the center of the thickness, as polished. There are no regions of internal damage (like internal voids or cracks), indicating that the mechanism is only related to surface effects.
42
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - As polished micrographyDf - In the Center of the Thickness
SAMPLE 3, CLOSE TO THE SURFACE OF SIDE A - Micrography, as polished, of the oxides at the process side. In this region there is an oxide layer, not continuous but with no localized penetrations.
43
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - As polished micrographyDf - At the Surface

+3 more from this case →

ML00162 — Valve Body Crack Growth from Weld DefectsM - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Low magnification micrography at the weld repair close to the internal surface of the valve body, in a longitudinal section. Weld metal to the right and heat affected zone to the left.
30
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 - Weld Repair
Micrography of the weld repair at the fusion line. At this magnification it is possible to identify several voids at interdendritic positions.
26
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 - Weld Repair
Micrographic detail of the weld metal presenting hot cracks, at interdendritic positions, interconected.
28
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 - Weld Metal
Microstructure of the weld metal close to the fusion line, showing that the dilution effects created zones of higher carbon content, creating a martensitic plus retained austenite microstructure.
29
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 - Weld Metal
Micrography in low magnification of the cracks in the repair weld metal, showing the dendritic aspect of the hot cracks, formed during welding due to the high content of impurities in a high strength weld metal.
26
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 - Weld Metal