ISO

2 cases · 10 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Application: Subsea Capture method: Optical Microscope Detail focus: Damage clear all

ISO — sub-branches

898-1 2

Results

SortNewestOldestTitle A-ZTitle Z-A
Micrography of the longitudinal section of the bolt, at the fracture (top of the figure), starting from the bottom of the thread (to the left side of the figure). The presence of the coating at the bolt surface shows that the fracture occurred without corrosion. The rusted aspect of the fracture is associated to corrosion products after the rupture has occurred, also suggesting that the bolts were fractured and remained in service for some time after the failure occurred.
65
VIEW
ML00126 / Mar.2018
Hydrogen Fracture of Subsea Allen Bolts
M - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Cm - As polished micrographyDf - Fracture
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

More from these cases

ML00126 — Hydrogen Fracture of Subsea Allen BoltsM - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Micrography, after NItal etching, of the longitudinal section of the bolt, at the fracture (top of the figure), starting from the bottom of the thread (to the left side of the figure). The presence of the coating at the bolt surface shows that the fracture occurred without corrosion.
56
VIEW
ML00126 / Mar.2018
Hydrogen Fracture of Subsea Allen Bolts
M - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Fracture
Micrography of the longitudinal section of the bolt, in the center of the thickness, showing at the fracture surface (top of the figure), secondary cracks that are perpendicular to the fracture, associated to segregation bands.
55
VIEW
ML00126 / Mar.2018
Hydrogen Fracture of Subsea Allen Bolts
M - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Secondary Cracks
Micrographic detail of the longitudinal section of the bolt, in the center of the thickness, showing the secondary cracks associated to segregation bands.
63
VIEW
ML00126 / Mar.2018
Hydrogen Fracture of Subsea Allen Bolts
M - Low Alloy Medium Carbon QTP - Coated ProductAp - SubseaCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Secondary Cracks
ML00073 — Hydrogen Cracking of a LAS Subsea FastenerM - Low Alloy Medium Carbon QTP - FastenerAp - SubseaCd - Hydrogen Embrittlement
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
Micrographic detail of the intergranular morphology of the internal hydrogen cracks.
44
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