Optical Microscope

2 cases · 5 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Product: Forging Condition: Damage Detail focus: Heat Affected Zone clear all

Optical Microscope — sub-branches

NaOH Electrolytic Etched Micro 4Nital Etched Micrography by OM 1

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Fusion line of the forging side, in the cap, showing the weld metal (to the top of the image) and the base metal (to the bottom of the image). The heat affected zone hardness is about 270HV10.
108
VIEW
ML00178 / Jan.2022
Cold cracks in Cr-Mo Welded Forging
M - CrMo SteelP - ForgingAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Micrography of the valve at the welded joint of the body to the insert (fillet weld). The cracking was arrested at the position of this welded joint because the structures of the weld metal, insert and heat affected zones are tough (austenitic in the weld metal and insert, and free from sigma in the HAZ) .
46
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Heat Affected Zone

More from these cases

ML00134 — Brittle Fracture of a Superduplex Valve BodyM - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Micrographic detail of the fusion line of the welded joint of the body to the insert (fillet weld). The cracking was arrested at the position of this welded joint because the structures of the weld metal, insert and heat affected zones are tough (austenitic in the weld metal and insert, and free from sigma in the HAZ) .
39
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Heat Affected Zone
Micrography of the valve at the welded joint of the body to the insert (fillet weld). The heat affected zone shows that the sigma phase was removed, which means that the base metal was degradated and during welding the thermal cycle created a condition to remove the sigma phase (dissolve it).
38
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Heat Affected Zone
Micrographic detail of the heat affected zone of the valve to the insert joint showing that the sigma phase was removed, which means that the base metal was degradated and during welding the thermal cycle created a condition to dissolve the sigma phase.
39
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Heat Affected Zone