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5 cases · 12 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Capture method: Electrolytic Etch Micrography by SEM clear all

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Micrographic detail by scanning electron microscopy of the interface between the two thermal spray layers, the first one in stainless steel (bottom of the figure) and the second one, at the surface,in tungsten carbide (top of the figure). The composition of the first layer is similar to the base metal (lean duplex) and the composition of the second layer is WC in a Co matrix.
16
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - Electrolytic Etch Micrography by SEMDf - Thermal Spray Layer
Image by scanning electron microscopy of the metallurgically bonded interface of the internally cladded pipe. It is a seamless pipe in a low alloy steel X70 cladded by welding overlay of Alloy 625 (by automatic GTAW process). The region is a detail of the interface inside the Ni alloy weld metal, presenting columnar grains and intragranular preciptation. The pipe was heat treated before bending (solution annealing) and after bending (quenching and tempering to meet X70 grade). The microhardness of this region is higher than the value obtained out of this region, in the overlay.
656
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Electrolytic Etch Micrography by SEMDf - Clad Interface
Image by scanning electron microscopy of the metallurgically bonded interface of the composite seamless tube (carbon steel externally claded with stainless steel), in the side of the stainless steel where a strain hardening effect plus a carbide precipitation in twins is shown. The hardness of this region (279 HV0.3) is a lot higher than the value obtained out of this region (167 HV0.3) for the same stainless steel.
814
VIEW
ML00056 / May.2018
Seamless Tube Externally Cladded with SS
M - Carbon Steel / Stainless SteelP - CladdingAp - Pulp and PaperCd - Removed From Service
Cm - Electrolytic Etch Micrography by SEMDf - Clad Interface
Micrographic detail of the flange base metal presenting a coarse duplex ferritic austenitc structure and detrimental phases associated to the ferritic structure.
47
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 - Electrolytic Etch Micrography by SEMDf - Duplex structure
Micrographic detail of the cracking, associated to the ferrite network, that presents both corrosion (preferential dissolution) and fracture (clevage) aspects.
128
VIEW
ML00002 / Jan.2018
Preferential Dissolution and Cracks in SDSS
M - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Cm - Electrolytic Etch Micrography by SEMDf - Crack

More from these cases

ML00147 — WC Layer Detached from a Cast Lean DuplexM - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Micrographic detail of the first thermal spray layer, in stainless steel with the same composition of the base metal (lean duplex).
16
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - Electrolytic Etch Micrography by SEMDf - Thermal Spray Layer
Micrographic detail, by scanning electron microscopy, of the duplex, austenitic and ferritic, structure with sigma phase.
16
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - Electrolytic Etch Micrography by SEMDf - Sigma
ML00132 — Seamless Pipe Overlaid with Alloy 625M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Image by scanning electron microscopy of the interface of the internally cladded pipe. It is a seamless pipe in low alloy steel X70 overlaid with Alloy 625 (by automatic GTAW process). The region is a detail in the side of the Ni alloy weld metal, presenting transgranular precipitation. The pipe was heat treated before bending (solution annelaing) and after bending (quenching and tempering to meet X70 grade). The microhardness of this region is higher than the value obtained out of this region, in the overlay.
42
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Electrolytic Etch Micrography by SEMDf - Clad Interface
Image by scanning electron microscopy of the interface of the internally cladded pipe, seamless low alloy steel X70 overlaid with Alloy 625 (by automatic GTAW process) and presenting maximum iron content of 5% at the thickness of 3 mm (the qualified thickness).
36
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Electrolytic Etch Micrography by SEMDf - Clad Interface
ML00056 — Seamless Tube Externally Cladded with SSM - Carbon Steel / Stainless SteelP - CladdingAp - Pulp and PaperCd - Removed From Service
The scanning electron microscopy image details the strain hardened layer with carbide precipitation at twins, in the stainless steel side very close to the interface.
80
VIEW
ML00056 / May.2018
Seamless Tube Externally Cladded with SS
M - Carbon Steel / Stainless SteelP - CladdingAp - Pulp and PaperCd - Removed From Service
Cm - Electrolytic Etch Micrography by SEMDf - Strain Hardened
ML00049 — Pipe to Flange Welded Joint in a 14" ND Superduplex SpoolM - Super Duplex Stainless SteelP - Piping spoolAp - Oil and GasCd - Removed From Service
Micrographic detail of the flange base metal presenting a coarse duplex ferritic austenitc structure and detrimental phases associated to the ferritic structure.
39
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 - Electrolytic Etch Micrography by SEMDf - Duplex structure
ML00002 — Preferential Dissolution and Cracks in SDSSM - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Micrographic detail of the ferrite network with evidences of precipitation/formation of detrimental phases. NaOH solution was adopted for the electrolytic etching.
86
VIEW
ML00002 / Jan.2018
Preferential Dissolution and Cracks in SDSS
M - Super Duplex Stainless SteelP - Fabrication WeldAp - PipingCd - Preferential Dissolution
Cm - Electrolytic Etch Micrography by SEMDf - Delta ferrite