Micrography by OM

27 cases · 73 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

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The as polished micrography of a longitudinal section of the pin, showing several microcracks associated to the chromium layer.
56
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Micrography by OMDf - Hard Chromium Layer
Micrography of the pin longitudinal section (transverse to the fracture), as polished. The fracture (in the top of the figure) is flat and it is possible to see secondary cracks with intergranular morphology.
40
VIEW
ML00088 / Dec.2017
Hydrogen Cracking of an API 5D S135 Drill Pipe
M - Low Alloy Medium Carbon QTP - Drill PipeAp - SubseaCd - Hydrogen Embrittlement
Cm - Micrography by OMDf - Secondary Cracks
Micrography of a longitudinal section of the bolt, as polished, presenting brittle cracks, transverse to the bolt axis.
1241
VIEW
ML00077 / Jun.2018
Hydrogen Cracking of LAS Subsea Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Micrography by OMDf - Cracks
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
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 pipe in a longitudinal section, close to the external surface, showing a pit (adjacent to the through wall cracking). The corrosion spt is not associated to any microstructural feature.
61
VIEW
ML00012 / Aug.2017
Vibration Induced Fatigue in a 316/316L SS
M - Austenitic Stainless SteelP - Seamless PipeAp - OffshoreCd - Vibration Induced Fatigue
Cm - Micrography by OMDf - Pitting
Micrography of the cast rim, base metal, in the as polished condition, showing the dendrites of alpha aluminum and interdendritic eutectic Si/alpha, silicon particles in a coalesced condition that sugegsts a solution annealed treatment.
119
VIEW
ML00070 / Jan.2019
Automotive Light Alloy Wheel Repaired By Welding
M - Aluminum Silicon MagnesiumP - RimAp - AutomotiveCd - Removed From Service
Cm - Micrography by OMDf - Base Metal
The micrography in the as polished condition of the longitudinal section of the pipe close to the washout, shows that at the tool mark tip (notch from the external surface) a fatigue crack already started from a corroded region (pitting).
187
VIEW
ML00068 / Sep.2020
Corrosion Fatigue of a 5" Drill Pipe
M - Low Alloy Medium Carbon QTP - Seamless PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Micrography by OMDf - Pitting

More from these cases

ML00081 — Hydrogen Cracking of a Chromium Plated Carburized PinM - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
The as polished micrography of a longitudinal section of the pin, showing that under the white layer of hard chromium (about 10 microns thick), there are already intergranular microcracks.
52
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Micrography by OMDf - Hard Chromium Layer
ML00077 — Hydrogen Cracking of LAS Subsea BoltsM - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
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.
104
VIEW
ML00077 / Jun.2018
Hydrogen Cracking of LAS Subsea Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Micrography by OMDf - Brittle Cracks
Micrography of a longitudinal section of the bolt, as polished, presenting brittle Intergranular and transgranular cracks, transverse to the bolt axis.
94
VIEW
ML00077 / Jun.2018
Hydrogen Cracking of LAS Subsea Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
Cm - Micrography by OMDf - Longitudinal Section
ML00070 — Automotive Light Alloy Wheel Repaired By WeldingM - Aluminum Silicon MagnesiumP - RimAp - AutomotiveCd - Removed From Service
Micrographic detail of the cast rim, base metal, in the as polished condition, showing the dendrites of alpha aluminum and interdendritic eutectic Si/alpha, silicon particles in a coalesced condition that sugegsts a solution annealed treatment.
74
VIEW
ML00070 / Jan.2019
Automotive Light Alloy Wheel Repaired By Welding
M - Aluminum Silicon MagnesiumP - RimAp - AutomotiveCd - Removed From Service
Cm - Micrography by OMDf - Base Metal
ML00068 — Corrosion Fatigue of a 5" Drill PipeM - Low Alloy Medium Carbon QTP - Seamless PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Micrographic detail, in the as polished condition, of the corrosion fatigue crack.
89
VIEW
ML00068 / Sep.2020
Corrosion Fatigue of a 5" Drill Pipe
M - Low Alloy Medium Carbon QTP - Seamless PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Micrography by OMDf - Fatigue Crack