Optical Microscope

3 cases · 25 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Microstructure: Ferritic Bainitic Standard: UNS clear all

Optical Microscope — sub-branches

Nital Etched Micrography by OM 25

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The longitudinal section of the shaft, in the center of the thickness, shows a coarse structure, and a ferritic/bainitic structure with pearlite islands.
97
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 - Longitudinal Section
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 a longitudinal section of the shell plate base metal, presenting a typical ferritic-perlitic microstructure.
149
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite

More from these cases

ML00152 — Low Alloy Steel Pump ShaftM - High Strength Low AlloyP - ShaftAp - Oil and GasCd - Removed From Service
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
The longitudinal section of the shaft, at the surface, also shows a coarse structure, and a ferritic/bainitic structure with pearlite islands. There is only a small refining in the previous austenite grain boundaries, indicating that the material was not heat treated.
75
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 - Longitudinal Section
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
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 →

ML00008 — Cold Cracks in CMn Steel Pressure VesselM - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Higher magnification of the ferritic-perlitic microstructure of the shell plate in the longitudinal section.
129
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Cold cracking of the fillet weld adopted to attach a flat support into a vessel shell in the internal side, using an unsuitable welding procedure that created a too high hardness HAZ.
123
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks
Cold cracking of the fillet weld adopted to attach a flat support into a vessel shell in the internal side, using an unsuitable welding procedure that created a too high hardness HAZ. The cracks are mainly located at the fusion line.
118
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks
Cold cracking of the fillet weld adopted to attach a flat support into a vessel shell in the internal side, using an unsuitable welding procedure that created a too high hardness HAZ. Several internal cracks at the fusion line.
101
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks
Cold cracking of the fillet weld adopted to attach a flat support into a vessel shell using an unsuitable welding procedure, with a low preheating and no PWHT. Cracks propagated in the heat affected zone.
99
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks

+1 more from this case →