Optical Microscope

39 cases · 68 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Detail focus: Longitudinal Section clear all

Optical Microscope — sub-branches

As polished micrography 1FeCl3+HCl+H2O Etched Micro 1Kalling Etched Micrography by OM 16Micro by OM, HCl + Ethanol + Picric Acid 2Micro by OM, picric acid+FeCl3+H2O etch 1Micrography by OM 2Micrography by OM using A262 Method A 1NaOH Electrolytic Etched Micro 2Nital Etched Micrography by OM 38Oxalic Acid Electrolytic Etch 4

Results

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Micrography of a longitudinal section, in the center, of the broken 5/8" bolt, presenting an aged martensitic structure. There are vertical "lines" that correspond to segregation bands due to the forming direction. These bands are evident only using low magnification microscopy.
168
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Longitudinal Section
Optical micrography of the longitudinal section of the drill collar, in the center of the thickness, presenting slightly elongated grains of fully austenitic microstructure, cold worked. The material presented 38HRc hardness.
57
VIEW
ML00135 / May.2018
MIC of a Non Magnetic Drilling Tool
M - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Longitudinal Section
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
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
The fracture of the bolt occurred associated to the bottom of the thread. Compare this photo with the previous one to understand where the fracture started.
115
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
As polished micrographic aspect of the longitudinal section of the cylinder, at the surface, in a region where the damage is in the begining. It is possible to see that there are two layers at the surface. A first Ni layer, 300HV average hardness, over the low carbon steel substrate, 200HV average hardness, and a chromium plated layer, 1100HV average hardness and several discontinuities.
62
VIEW
ML00128 / Apr.2018
MIC of a Stored Hydraulic Cylinder
M - Low Carbon SteelP - Chromium PlatedAp - OffshoreCd - Localized Dissolution
Cm - Micrography by OMDf - Longitudinal Section
Micrography of a longitudinal section of the forged bar in the center of the thickness. Ferrite and austenite. Coarse structure.
61
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - NaOH Electrolytic Etched MicroDf - Longitudinal Section
Micrography of a longitudinal section of the core wire, 2.0 mm diameter, in the center of the thickness, showing a strain hardened pearlitic structure.
89
VIEW
ML00117 / Jan.2018
High Carbon Steel Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Longitudinal Section

More from these cases

ML00139 — Hydrogen Fracture of a 17-4 PH Allen BoltM - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Micrography of a longitudinal section of the 5/8" bolt, at the bottom of the thread, presenting a refined structure compared to the center of the bolt and a mark at the thread flank that was probably created during tightening of the bolt.
95
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Longitudinal Section
Micrography of a longitudinal section of the bolt, close to the fracture surface (top of the figure), The fracture started at the surface (left side) in a position close to the bolt body to bolt head transition.
58
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - As polished micrographyDf - Longitudinal Section
Micrography of a longitudinal section, in the center of a non-broken bolt that operated in the same assembling, presenting an aged martensitic structure, similar to the broken bolt.
41
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Longitudinal Section
Micrography of a longitudinal section of the non-broken 5/8" bolt, at the transition between the threaded body and the head, showing a variation in the grain size (of the previous austenite) and evidences of a deformed structure at this transition.
41
VIEW
ML00139 / Jun.2018
Hydrogen Fracture of a 17-4 PH Allen Bolt
M - Precipitation Hardened Stainless SteelP - Allen BoltAp - SubseaCd - Hydrogen Embrittlement
Cm - Kalling Etched Micrography by OMDf - Longitudinal Section
ML00135 — MIC of a Non Magnetic Drilling ToolM - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Optical micrography of the longitudinal section of the drill collar, in the center of the thickness, presenting slightly elongated grains of fully austenitic microstructure, cold worked.
62
VIEW
ML00135 / May.2018
MIC of a Non Magnetic Drilling Tool
M - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Longitudinal Section
ML00123 — Non Qualified Superduplex for SubseaM - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Micrography of a longitudinal section of the forged bar in the center of the thickness. Ferrite and austenite. The average austenite spacing is 80 microns, a lot larger than the maximum allowed in the specification, of 30 microns. No detrimental phases were identified at the ferrite/austenite interfaces, but the ferrite phase presented a rough aspect. Higher magnification analysis would be required to identify precipitation.
53
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - NaOH Electrolytic Etched MicroDf - Longitudinal Section
ML00117 — High Carbon Steel Wire RopeM - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Typical manufacturing
Micrography of a longitudinal section of the core wire, 2.0 mm diameter, at the surface of the wire, showing that the wire presents no protective layer (not galvanized) and the microstructure is strain hardened, aligned.
60
VIEW
ML00117 / Jan.2018
High Carbon Steel Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrography of a longitudinal section of the internal strand wire, 2.6 mm diameter, in the center of the thickness, showing a strain hardened pearlitic structure.
37
VIEW
ML00117 / Jan.2018
High Carbon Steel Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrography of a longitudinal section of the strand internal layer wire, 2.6 mm diameter, at the surface, showing that the wire presents no protective layer (not galvanized) and the microstructure is strain hardened, aligned.
32
VIEW
ML00117 / Jan.2018
High Carbon Steel Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrography of a longitudinal section of the strand external layer, wire of 3.8 mm diameter, in the center of the thickness, showing a strain hardened pearlitic structure.
19
VIEW
ML00117 / Jan.2018
High Carbon Steel Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrography of a longitudinal section of the strand external layer wire, 3.8 mm diameter, at the surface, showing that the wire presents no protective layer (not galvanized) and the microstructure is strain hardened, aligned.
17
VIEW
ML00117 / Jan.2018
High Carbon Steel Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Longitudinal Section