NaOH Electrolytic Etched Macro

4 cases · 9 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Microstructure: Detrimental phases clear all

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Macrographic aspect of the sleeve longitudinal section where the coating was applied in the external side (top of the figure). It is possible to see that the sleeve was manufactured by centrifugal casting, with elongated grains from the external side, and equiaxial grains close to the internal side (bottom of the figure). There is a weaved interface between the sleeve and the first layer of thermal spray coating, 1 mm thick; and a second layer of thermal spray coating, 0.2mm thick (almost imperceptible at this low magnification).
49
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - NaOH Electrolytic Etched MacroDf - Coating Layer
Aspect of the valve body after cutting a slice containg the crack and the welded joint of the body to the insert (fillet weld). The cracking was arrested at the position of this welded joint.
56
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 MacroDf - Welded Joint
Macrography of the pipe to flange weld. Transverse section identifying the regions of the base materials, heat affected zones and weld metal, which microstructures are presented in this ML.
527
VIEW
ML00049 / Apr.2017
Pipe to Flange Welded Joint in a 14" ND Superduplex Spool
M - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Cm - NaOH Electrolytic Etched MacroDf - Welded Joint
Macrography of a longitudinal section of the flange to pipe weld, cracked in the flange. Pipe thickness, measured, is 5 mm. Flange thickness at the welded region is 7.5 mm. The macro was etched using NaOH solution, electrolytic.
181
VIEW
ML00002 / Jan.2018
Preferential Dissolution and Cracks in SDSS
M - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Cm - NaOH Electrolytic Etched MacroDf - Longitudinal Section

More from these cases

ML00147 — WC Layer Detached from a Cast Lean DuplexM - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Macrography of a longitudinal section showing the region where the surface layer was detached (top of the figure), creating a lack of sealing condition.
23
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - NaOH Electrolytic Etched MacroDf - Thermal Spray Layer
ML00134 — Brittle Fracture of a Superduplex Valve BodyM - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Macrographic detail of the valve at the welded joint of the SDSS body (left side of the figure) to the Alloy 625 insert (right side of the figure), by a fillet weld. The cracking was arrested at the position of this welded joint.
48
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 MacroDf - Welded Joint
ML00049 — Pipe to Flange Welded Joint in a 14" ND Superduplex SpoolM - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Macrography of the pipe heat affected zone.
55
VIEW
ML00049 / Apr.2017
Pipe to Flange Welded Joint in a 14" ND Superduplex Spool
M - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Cm - NaOH Electrolytic Etched MacroDf - Heat Affected Zone
Macrography of the flange HAZ. The macroscopic aspect shows a remarkable modified region.
56
VIEW
ML00049 / Apr.2017
Pipe to Flange Welded Joint in a 14" ND Superduplex Spool
M - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Cm - NaOH Electrolytic Etched MacroDf - Heat Affected Zone
Micrographic detail of the center of the weld metal (fill pass). Duplex ferritic austenitic structure.
26
VIEW
ML00049 / Apr.2017
Pipe to Flange Welded Joint in a 14" ND Superduplex Spool
M - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Cm - NaOH Electrolytic Etched MacroDf - Weld Metal in the Center