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13 cases · 120 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Product: Welded Joint Capture method: Optical Microscope clear all

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Microstructural analysis of the valve body structure, close to the position where the cracking has occurred. The structure is ferritic austenitic, with a large amount of detrimental phases associated to the ferritic structure, probably sigma phase.
106
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 - Sigma
The micrographic aspect of the cracks in a section transverse to the weld (the removed sample), shows that there are cracks with different sizes, the larger are filled with products that indicate they were opened for longer times.
67
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Intergranular Cracking
Micrography of the base metal presenting a banded microstructure in the longitudinal section of the pipe.
51
VIEW
ML00066 / May.2017
GMAW Welded Joint in 9%Ni Alloy Steel
M - Nickel Alloy SteelP - Welded Testpiece for QualificationAp - PipelineCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Through wall cracking in the longitudinal seam weld of the fitting. Several cracks, longitudinal to the weld, were created by the connection of voids in the weld metal, associated to a strong microstructural evolution.
191
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - Cracks
Micrography of a longitudinal section of the pipe showing that the carbon steel pipe is slightly banded and there is a decarburized layer at the solid solution welded interface. The stainless steel structure (in the right side of the figure) is not revealed using the Nital etch.
125
VIEW
ML00056 / May.2018
Seamless Tube Externally Cladded with SS
M - Carbon Steel / Stainless SteelP - CladdingAp - Pulp and PaperCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Original casting base metal presenting a coarse martensitic structure with a small amount of delta ferrite.
50
VIEW
ML00055 / Apr.2017
CA6NM Blade Remanufactured by Welding
M - Martensitic Stainless SteelP - Remanufacture by WeldingAp - EnergyCd - Removed From Service
Cm - Kalling Etched Micrography by OMDf - Base Metal Left Side
Base metal micrographic detail presenting a tempered martensitic microstructure.
27
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Kalling Etched Micrography by OMDf - Base Metal
Micrographic detail of the fatigue cracking at the margin of the flange to shell fillet weld.
484
VIEW
ML00050 / Nov.2017
Fatigue Failure of a 316SS Pressure Stabilizer
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
Cm - Micrography by OM using A262 Method ADf - Fatigue Crack

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 valve body structure, close to the position where the cracking has occurred. The structure is ferritic austenitic, with a large amount of detrimental phases associated to the ferritic structure, probably sigma phase.
102
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 - Sigma
Metallographic detail of the large amount of sigma phase, associated to the ferritic structure.
105
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 - Sigma
Microstructural analysis of the valve body structure, far from the position where the cracking has occurred, in the bottom of the body. The structure is ferritic austenitic, with some sigma phase, not in a large amount, indicating the valve structure was not uniform.
67
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 - Ferrite and Austenite
Micrographic detail of the valve body structure, far from the position where the cracking has occurred, in the bottom of the body. The structure is ferritic austenitic, with some sigma phase, not in a large amount, indicating the valve structure was not uniform.
63
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 - Ferrite and Austenite
Micrographic detail of the valve body structure, far from the position where the cracking has occurred, in the bottom of the body. The structure is ferritic austenitic, with some sigma phase, not in a large amount, indicating the valve structure was not uniform.
61
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 - Ferrite and Austenite

+8 more from this case →

ML00071 — Reheating Cracking of a CrMo Vessel WeldM - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Micrographic aspect of opened cracks, filled with oxides.
63
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks
Micrographic details of opened cracks, filled with oxides.
56
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks
Micrographic aspect of thin cracks.
59
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks
Micrographic details of thin cracks.
63
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks
ML00066 — GMAW Welded Joint in 9%Ni Alloy SteelM - Nickel Alloy SteelP - Welded Testpiece for QualificationAp - PipelineCd - Welding
Micrographic detail of a longitudinal section of the base metal presenting a quenched and tempered microstructure.
49
VIEW
ML00066 / May.2017
GMAW Welded Joint in 9%Ni Alloy Steel
M - Nickel Alloy SteelP - Welded Testpiece for QualificationAp - PipelineCd - Welding
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrographic detail of the low temperature heat affected zone of the pipe. The intercritical temperature (IC) is evident in the decorated grain boundaries of the previous austenite.
42
VIEW
ML00066 / May.2017
GMAW Welded Joint in 9%Ni Alloy Steel
M - Nickel Alloy SteelP - Welded Testpiece for QualificationAp - PipelineCd - Welding
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Micrography of the fusion line close to the cap pass (CP). The weld metal (non etched) is in the left side.
43
VIEW
ML00066 / May.2017
GMAW Welded Joint in 9%Ni Alloy Steel
M - Nickel Alloy SteelP - Welded Testpiece for QualificationAp - PipelineCd - Welding
Cm - Nital Etched Micrography by OMDf - Fusion Line
Micrography of the heat affected zone, a little far from the fusion line, close to the base metal.
40
VIEW
ML00066 / May.2017
GMAW Welded Joint in 9%Ni Alloy Steel
M - Nickel Alloy SteelP - Welded Testpiece for QualificationAp - PipelineCd - Welding
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Micrographic detail of the fusion line in the center of the thickness, where the heat affected zone was reheated by the subsequent passes.
34
VIEW
ML00066 / May.2017
GMAW Welded Joint in 9%Ni Alloy Steel
M - Nickel Alloy SteelP - Welded Testpiece for QualificationAp - PipelineCd - Welding
Cm - Nital Etched Micrography by OMDf - Fusion Line

+8 more from this case →

ML00061 — Creep in a Seam Weld of a 304H SS FittingM - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Micrography of a longitudinal section of the fitting, at the base metal, presenting an austenitic structure with intergranular and transgranular precipitation as a result of microstructural evolution.
44
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - Base Metal
Micrographic detail of the fitting base metal, presenting an austenitic structure with intergranular and transgranular precipitation as a result of microstructural evolution.
40
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - Base Metal
Micrography of a transverse section of the seam weld, close to the internal surface, presenting several cracks perpendicular to the thickness.
37
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - Close to the Internal Surface
Micrographic detail of the seam weld close to the internal surface, presenting the needles that are the result of microsctructural evolution and cracks filled with oxides.
36
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - Close to the Internal Surface
Micrography of a transverse section of the seam weld, in the middle of the thickness, presenting several parallel cracks.
27
VIEW
ML00061 / Apr.2017
Creep in a Seam Weld of a 304H SS Fitting
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Creep
Cm - Micrography by OM using A262 Method ADf - In the Center of the Thickness

+7 more from this case →

ML00056 — Seamless Tube Externally Cladded with SSM - Carbon Steel / Stainless SteelP - CladdingAp - Pulp and PaperCd - Removed From Service
Micrography of a longitudinal section of the pipe showing the carbon steel pipe , internal.
122
VIEW
ML00056 / May.2018
Seamless Tube Externally Cladded with SS
M - Carbon Steel / Stainless SteelP - CladdingAp - Pulp and PaperCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of a longitudinal section of the pipe showing the stainless steel pipe , external.
99
VIEW
ML00056 / May.2018
Seamless Tube Externally Cladded with SS
M - Carbon Steel / Stainless SteelP - CladdingAp - Pulp and PaperCd - Removed From Service
Cm - Micrography by OM using A262 Method ADf - Austenite
Micrographic detail of the interface in the longitudinal section of the pipe showing the Vickers (300g) microhardness values, close to the interface in the carbon steel side and in the stainless steel side. Although the Nital etch does not allow to reveal the structure in the stainless steel side, the high hardness values show that the structure is different.
113
VIEW
ML00056 / May.2018
Seamless Tube Externally Cladded with SS
M - Carbon Steel / Stainless SteelP - CladdingAp - Pulp and PaperCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrographic detail of the interface in the longitudinal section of the pipe showing the decarburized layer at the solid solution welded interface. The stainless steel structure (in the right side of the figure) is not revealed using the Nital etch.
80
VIEW
ML00056 / May.2018
Seamless Tube Externally Cladded with SS
M - Carbon Steel / Stainless SteelP - CladdingAp - Pulp and PaperCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrography of the interface between the carbon steel that is strongly etched by the electrolytic oxalic acid (in the left side of the figure) and the stainless steel, in the longitudinal section of the pipe. There is a strain hardened layer very close to the interface, at the stainless steel side.
79
VIEW
ML00056 / May.2018
Seamless Tube Externally Cladded with SS
M - Carbon Steel / Stainless SteelP - CladdingAp - Pulp and PaperCd - Removed From Service
Cm - Micrography by OM using A262 Method ADf - Longitudinal Section

+2 more from this case →

ML00055 — CA6NM Blade Remanufactured by WeldingM - Martensitic Stainless SteelP - Remanufacture by WeldingAp - EnergyCd - Removed From Service
Inserted casting base metal presenting a coarse martensitic structure with a small amount of delta ferrite.
24
VIEW
ML00055 / Apr.2017
CA6NM Blade Remanufactured by Welding
M - Martensitic Stainless SteelP - Remanufacture by WeldingAp - EnergyCd - Removed From Service
Cm - Kalling Etched Micrography by OMDf - Base Metal Right Side
Micrography of the original casting blade at the fusion line of the welding with the insert casting. There is a refinement effect on the coarse base metal structure.
24
VIEW
ML00055 / Apr.2017
CA6NM Blade Remanufactured by Welding
M - Martensitic Stainless SteelP - Remanufacture by WeldingAp - EnergyCd - Removed From Service
Cm - Kalling Etched Micrography by OMDf - HAZ Left Side
Micrographic detail of the fusion line of the original casting blade welded to the insert casting. There is a refinement effect on the coarse base metal structure.
21
VIEW
ML00055 / Apr.2017
CA6NM Blade Remanufactured by Welding
M - Martensitic Stainless SteelP - Remanufacture by WeldingAp - EnergyCd - Removed From Service
Cm - Kalling Etched Micrography by OMDf - HAZ Left Side
Micrography of the inserted casting at the heat affected zone of the welding with the original casting. There is a refinement effect on the coarse base metal structure.
20
VIEW
ML00055 / Apr.2017
CA6NM Blade Remanufactured by Welding
M - Martensitic Stainless SteelP - Remanufacture by WeldingAp - EnergyCd - Removed From Service
Cm - Kalling Etched Micrography by OMDf - HAZ Right Side
Micrographic detail of the fusion line of the inserted casting welded to the original casting. There is a refinement effect on the coarse base metal structure.
15
VIEW
ML00055 / Apr.2017
CA6NM Blade Remanufactured by Welding
M - Martensitic Stainless SteelP - Remanufacture by WeldingAp - EnergyCd - Removed From Service
Cm - Kalling Etched Micrography by OMDf - HAZ Right Side

+2 more from this case →

ML00045 — Subsea Tubular F6NM Martensitic SSM - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Micrographic detail of the heat-affected zone close to the base metal.
29
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Kalling Etched Micrography by OMDf - Heat Affected Zone
Micrographic detail of the heat-affected zone close to the fusion line.
31
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Kalling Etched Micrography by OMDf - Heat Affected Zone
Micrographic detail of the tempered martesite weld metal close to the fusion line. The columnar grains can be observed .
23
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Kalling Etched Micrography by OMDf - Weld Metal
Micrography of the base metal showing a tempered martensitic microstructure.
30
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Kalling Etched Micrography by OMDf - Base Metal
Micrography of the heat-affected zone. The fusion line is in the right and the coarse structure of the base metal is refined at the heat affected zone.
28
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Kalling Etched Micrography by OMDf - Heat Affected Zone

+8 more from this case →

ML00050 — Fatigue Failure of a 316SS Pressure StabilizerM - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
The shell plate micrography showed an austenitic structure.
101
VIEW
ML00050 / Nov.2017
Fatigue Failure of a 316SS Pressure Stabilizer
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
Cm - Micrography by OM using A262 Method ADf - Austenite
The micrography of the welded joint between the flange and the shell, in a region that was through wall cracked, the fracture propagating in the shell plate base metal.
74
VIEW
ML00050 / Nov.2017
Fatigue Failure of a 316SS Pressure Stabilizer
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
Cm - Micrography by OM using A262 Method ADf - Welded Joint
The micrography of the welded joint between the flange and the shell, in a region that was not yet macroscopically cracked, presented a fatigue crack from the margin of the fillet weld.
71
VIEW
ML00050 / Nov.2017
Fatigue Failure of a 316SS Pressure Stabilizer
M - Austenitic Stainless SteelP - Fabrication WeldAp - Chemical IndustryCd - Mechanical Fatigue
Cm - Micrography by OM using A262 Method ADf - Welded Joint