Optical Microscope

37 cases · 316 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Application: Oil and Gas clear all

Optical Microscope — sub-branches

As polished micrography 16Chromic Acid Electrolytic Etched 6FeCl3+HCl+H2O Etched Micro 7Kalling Etched Micrography by OM 50Micrography by OM 6Micrography by OM using A262 Method A 15Micrography by OM, HF + HNO3 + H2O etch 2NaOH Electrolytic Etched Micro 23Nital Etched Micrography by OM 175Oxalic Acid Electrolytic Etch 16

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The stud presents an austenitic structure, with primary and secondary precipitates of a size that is visible in low magnification microscopy.
55
VIEW
ML00075 / Jun.2018
Hydrogen Cracking of IN 718 Subsea Fasteners
M - NiCrFe AlloyP - StudAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Austenite
Micrographic aspect of the aged martensite structure of the 17-4 PH bolt, about 37 HRc.
94
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Martensite
Multiple intergranular cracks transverse to the bolt axis. Hydrogen assisted cracking due to cathodic protection of a high strenght steel. Micrography in the "as polished" condition.
472
VIEW
ML00073 / Jun.2018
Hydrogen Cracking of a LAS Subsea Fastener
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Micrography by OMDf - Intergranular Cracking
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
Micrography of the pipe base metal presenting a refined duplex ferritic austenitc structure, banded.
47
VIEW
ML00049 / Apr.2017
Pipe to Flange Welded Joint in a 14" ND Superduplex Spool
M - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Cm - NaOH Electrolytic Etched MicroDf - Duplex structure
The micrography of a transverse section of the shaft shows the granular austenitic structure close to the surface of the shaft.
67
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - At the Surface
13Cr SS longitudinal section micrography, at the collapsed region, showing a ferritic matrix structure (overtempered) with the previous austenite grain boundaries decorated by phases (carbides and probably martensite islands), indicating that the material was exposed to a high tempering temperature that created a partial austenitizing condition. It explains the material low toughness and lower strenght (than required).
437
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Longitudinal Section
Longitudinal section of the fitting in the center of the thickness (2"). Refined ferritic structure.
370
VIEW
ML00030 / Jan.2017
Forging for High Pressure Application
M - Microalloyed SteelP - Machined PartAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Bainitic Ferrite

More from these cases

ML00075 — Hydrogen Cracking of IN 718 Subsea FastenersM - NiCrFe AlloyP - StudAp - SubseaCd - Hydrogen Embrittlement
The stud structure evidences grain boundaries precipitation of probably delta phase (an overaging of the hardening precipitate).
49
VIEW
ML00075 / Jun.2018
Hydrogen Cracking of IN 718 Subsea Fasteners
M - NiCrFe AlloyP - StudAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Austenite
Micrography of a longitudinal section of the stud, at the fracture surface, in the thread.
44
VIEW
ML00075 / Jun.2018
Hydrogen Cracking of IN 718 Subsea Fasteners
M - NiCrFe AlloyP - StudAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Fracture
Micrographic detail of a longitudinal section of the stud, at the fracture surface, in the thread. It is possible to see primary precipitates (yellow) already cracked and intergranular propagation.
37
VIEW
ML00075 / Jun.2018
Hydrogen Cracking of IN 718 Subsea Fasteners
M - NiCrFe AlloyP - StudAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Intergranular Cracking
Micrography of a longitudinal section of the stud, at the fracture surface in the center of the thickness, showing a long secondary cracking (vertical in the left).
35
VIEW
ML00075 / Jun.2018
Hydrogen Cracking of IN 718 Subsea Fasteners
M - NiCrFe AlloyP - StudAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Secondary Cracks
Micrographic detail of the longitudinal section of the stud, at the secondary cracking.
27
VIEW
ML00075 / Jun.2018
Hydrogen Cracking of IN 718 Subsea Fasteners
M - NiCrFe AlloyP - StudAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Brittle Cracks
ML00074 — Hydrogen Cracking of a 17-4 PH Subsea BoltM - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Micrographic detail of the aged martensite structure of the 17-4 PH bolt, about 37 HRc.
73
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Martensite
Micrography of the longitudinal section of the bolt, at the bottom of the thread fillet, showing that the fracture is intergranular in this position.
71
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Longitudinal Section
Micrographic detail of intergranular cracks close to the fracture of the bolt, near the bolt surface where the macroscopi aspect was brittle.
82
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Intergranular Cracking
The micrography, in the "as polished" condition, of the longitudinal section of the bolt showing that there are non-continuous longitudinal cracks, intergranular, associated to regions of impurities, probably segregation bands, as evidenced by the grey elongated sulfide inclusions.
76
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Micrography by OMDf - Intergranular Cracking
Micrographic detail of the longitudinal cracks in the middle of the bolt, that generaate the secondary cracks that appear at the fracture surface.
79
VIEW
ML00074 / Jun.2018
Hydrogen Cracking of a 17-4 PH Subsea Bolt
M - Precipitation Hardened Stainless SteelP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Intergranular Cracking
ML00073 — Hydrogen Cracking of a LAS Subsea FastenerM - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Tempered martensitic structure of a longitudinal section of the fastener. Slightly banded material. Hardness level about 42 HRc.
59
VIEW
ML00073 / Jun.2018
Hydrogen Cracking of a LAS Subsea Fastener
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of a longitudinal section of the fastener, at the threat fillet, showing a transverse cracking.
68
VIEW
ML00073 / Jun.2018
Hydrogen Cracking of a LAS Subsea Fastener
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Cracking
Micrography of the secondary crack, in the fillet adjacent to the nut position, where it was opened to the surface.
65
VIEW
ML00073 / Jun.2018
Hydrogen Cracking of a LAS Subsea Fastener
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Cracking
Micrographic detail of the secondary crack, in the fillet adjacent to the nut position, where it was opened to the surface.
46
VIEW
ML00073 / Jun.2018
Hydrogen Cracking of a LAS Subsea Fastener
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Cracking
Thin intergranular cracks in the center of the bolt thickness. Not continuous and not opened to the surface.
46
VIEW
ML00073 / Jun.2018
Hydrogen Cracking of a LAS Subsea Fastener
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Intergranular Cracking

+1 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 →

ML00049 — Pipe to Flange Welded Joint in a 14" ND Superduplex SpoolM - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Micrographic detail of the pipe base metal presenting a refined duplex ferritic austenitc structure, banded.
55
VIEW
ML00049 / Apr.2017
Pipe to Flange Welded Joint in a 14" ND Superduplex Spool
M - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Cm - NaOH Electrolytic Etched MicroDf - Base Metal
Micrographic detail of the pipe base metal presenting a refined duplex ferritic austenitc structure, banded.
56
VIEW
ML00049 / Apr.2017
Pipe to Flange Welded Joint in a 14" ND Superduplex Spool
M - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Cm - NaOH Electrolytic Etched MicroDf - Duplex structure
Micrography of the flange base metal presenting a coarse duplex ferritic austenitc structure.
88
VIEW
ML00049 / Apr.2017
Pipe to Flange Welded Joint in a 14" ND Superduplex Spool
M - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Cm - NaOH Electrolytic Etched MicroDf - Duplex structure
Micrographic detail of the flange base metal presenting a coarse duplex ferritic austenitc structure. Detrimental phases associated to the ferritic structure.
62
VIEW
ML00049 / Apr.2017
Pipe to Flange Welded Joint in a 14" ND Superduplex Spool
M - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Cm - NaOH Electrolytic Etched MicroDf - Duplex structure
Micrography of the pipe heat affected zone. In the left the pipe base metal, with banded duplex structure; and in the right the weld metal, with Widmanstatten morphology of the structure.
43
VIEW
ML00049 / Apr.2017
Pipe to Flange Welded Joint in a 14" ND Superduplex Spool
M - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Cm - NaOH Electrolytic Etched MicroDf - Heat Affected Zone

+11 more from this case →

ML00041 — Fatigue Fracture of Inconel 718 Spline ShaftM - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Micrographic detail of the granular austenitic structure close to the surface of the shaft.
64
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - At the Surface
Granular austenitic structure close to the surface of the shaft.
61
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - Austenite
The micrography of a transverse section of the shaft shows a duplex grain size structure in the center of the shaft.
49
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - In the Center of the Thickness
The micrography of a transverse section of the shaft shows a duplex grain size structure in the center of the shaft. This conditions was probably generated due to the delta phase presented in segregated bands in the center of the original bar.
56
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - In the Center of the Thickness
Duplex grain size structure, austenitic. The small grains are probably due to the arresting effect of the delta phase during fabrication in high temperature.
47
VIEW
ML00041 / Jun.2017
Fatigue Fracture of Inconel 718 Spline Shaft
M - NiCrFe AlloyP - ShaftAp - Oil and GasCd - Vibration Induced Fatigue
Cm - Kalling Etched Micrography by OMDf - Duplex structure

+2 more from this case →

ML00039 — Collapse in Tubular 13CrM - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
13Cr SS in the longitudinal section, at the collapsed region. Non uniform structure (ferritic matrix and decorated prior austenite grain boundaries) that evidences an usuitable heat treatment during fabrication, and explains the material low strenght.
54
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Longitudinal Section
13Cr SS in the longitudinal section, at the collapsed region. Detail of the non uniform structure (ferritic matrix and decorated prior austenite grain boundaries) that evidences an usuitable heat treatment during fabrication, and explains the material low strenght.
48
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Prior Austenite Boundaries Decorated
13Cr SS in the transverse section, at the collapsed region, showing a non uniform structure that evidences an usuitable heat treatment during fabrication, and explains the material low strenght.
29
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Transverse Section
13Cr SS transverse section micrography, at the collapsed region, showing a ferritic matrix structure (overtempered) with the previous austenite grain boundaries decorated by phases (carbides and probably martensite islands), indicating that the material was exposed to a high tempering temperature that created a partial austenitizing condition. It explains the material low toughness and lower strenght (than required).
29
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Transverse Section
The micrography of the 13Cr SS in the transverse section, at the collapsed region, shows a ferritic matrix structure (overtempered) with the previous austenite grain boundaries decorated by phases (carbides and probably martensite islands), indicating that the material was exposed to a high tempering temperature that created a partial austenitizing condition. It explains the material low toughness and lower strenght (than required).
32
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Overtempered Structure

+3 more from this case →

ML00030 — Forging for High Pressure ApplicationM - Microalloyed SteelP - Machined PartAp - Oil and GasCd - Typical manufacturing
Longitudinal section of the fitting in the center of the thickness (2"). Refined ferritic structure.
67
VIEW
ML00030 / Jan.2017
Forging for High Pressure Application
M - Microalloyed SteelP - Machined PartAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Grain refined structure
Longitudinal section of the fitting in the center of the thickness (2"). Refined ferritic structure.
63
VIEW
ML00030 / Jan.2017
Forging for High Pressure Application
M - Microalloyed SteelP - Machined PartAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Grain refined structure