Optical Microscope

183 cases · 1637 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Optical Microscope — sub-branches

As polished micrography 128Chromic Acid Electrolytic Etched 7Eletrolytically Etched Micrography by OM 11FeCl3+HCl+Ethanol Etched Micro 15FeCl3+HCl+H2O Etched Micro 28Glyceregia Etched Micrography by OM 7H2SO4+HNO3+H3PO4 Etched Micro 4Kalling Etched Micrography by OM 202Keller Etched Micrography by OM 58Kroll Etched Micrography by OM 15Micro by OM, HCl + Ethanol + Picric Acid 12Micro by OM, picric acid+FeCl3+H2O etch 4Micrography by OM 73Micrography by OM using A262 Method A 80Micrography by OM, HF + HNO3 + H2O etch 8NH4OH+H2O+H2O2 Etched Micro 8NaOH Electrolytic Etched Micro 108Nital Etched Micrography by OM 801Oxalic Acid Electrolytic Etch 68

Results

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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
Close to the camshaft lobe surface, the chilled casting presents a white cast iron structure. Primary carbides and ledeburite with a hardness level about 50 HRc.
102
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Detail of the longitudinal section of the ring, showing a fully ferritic structure.
619
VIEW
ML00057 / Apr.2017
Low Carbon Steel of Segment Ring
M - Low Carbon SteelP - Machined PartAp - AutomotiveCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
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.
124
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
Micrography of the plate material presenting a granular austenitic structure, free from precipitation.
122
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Eletrolytically Etched Micrography by OMDf - Austenite
The micrography shows the region underbead, of the tube HAZ, responsible for the hydrogen cracking (fracture in the right side of the photo - black). The hardness of the HAZ is about 600 HV.
55
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracking

More from these cases

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

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ML00060 — Brittle Fracture of a Chilled Cast Iron CamshaftM - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Micrographic detail of the chilled structure. Primary carbides, ledeburite and perlite islands.
79
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
In the center of the shaft thickness the structure is perlitic with graphite in flakes, but there are also islands of ledeburite.
62
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrographic detail of the structure in the center of the shaft thickness. Perlitic matrix with graphite in flakes, and ledeburite islands.
53
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
In the intermediary position of the shaft thickness (T/4) the amount of perlite increases in the matrix and primary carbides decreases compared to the chilled surface.
54
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - T/4 of the external surface
Micrographic detail of the intermediary position of the shaft thickness (T/4). The amount of perlite increases in the matrix and primary carbides decreases compared with the chilled surface.
55
VIEW
ML00060 / Apr.2017
Brittle Fracture of a Chilled Cast Iron Camshaft
M - Chilled Cast IronP - ShaftAp - AutomotiveCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - T/4 of the external surface

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ML00057 — Low Carbon Steel of Segment RingM - Low Carbon SteelP - Machined PartAp - AutomotiveCd - Removed From Service
Longitudinal section of the ring, showing a fully ferritic structure.
128
VIEW
ML00057 / Apr.2017
Low Carbon Steel of Segment Ring
M - Low Carbon SteelP - Machined PartAp - AutomotiveCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
The longitudinal section of the ring reveals a very fine ferritic structure.
115
VIEW
ML00057 / Apr.2017
Low Carbon Steel of Segment Ring
M - Low Carbon SteelP - Machined PartAp - AutomotiveCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Transverse section of the ring presenting a fully ferritic structure, that presents a hardness level a little higher probably due to a cold forming effect.
93
VIEW
ML00057 / Apr.2017
Low Carbon Steel of Segment Ring
M - Low Carbon SteelP - Machined PartAp - AutomotiveCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Transverse Section
Transverse section of the ring presenting a fully ferritic structure, that presents a hardness level a little higher probably due to a cold forming effect.
54
VIEW
ML00057 / Apr.2017
Low Carbon Steel of Segment Ring
M - Low Carbon SteelP - Machined PartAp - AutomotiveCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Transverse Section
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 .
22
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.
29
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 →

ML00051 — Chloride SCC of 316 Heat Exchanger PlateM - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Micrographic detail of the austenitic microstructure of the heat exchanger plate, free from carbides that suggest the adoption of a material in a solution annealed condition, although the high hardness level indicates cold working.
109
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Eletrolytically Etched Micrography by OMDf - Austenite
Micrography presenting the transgranular morphology of the stress corrosion cracks of the austenitic plate. EDS analysis at the plate surface indicated high Cl peaks.
111
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Eletrolytically Etched Micrography by OMDf - Corrosion Cracking
Micrographic detail of a branch transgranular crack typical of CSCC. Moreover, there is no evidence of intergranular precipitation.
99
VIEW
ML00051 / Apr.2020
Chloride SCC of 316 Heat Exchanger Plate
M - Austenitic Stainless SteelP - Heat Exchanger PartAp - FPSOCd - Stress Corrosion
Cm - Micrography by OM using A262 Method ADf - Corrosion Cracking
ML00052 — Cold Cracks in API 5CT L80 Tube Welded to a Structural PartM - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Low carbon plate base metal presenting the ferritic perlitic structure.
55
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal
High Strenght Low Alloy steel tube, base metal, presenting the bainitic structure.
54
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of the low carbon steel plate at the fusion line, presenting a bainitic structure at the HAZ and ferritic structure in the weld metal.
82
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Fusion Line
The micrography shows the martensitic region of the tube HAZ responsible for the hydrogen cracking, presenting too high hardness level (600 HV). It is a fresh martensite since the joint was welded in one pass and there was no PWHT.
45
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography of the weld metal in the center of the fillet showing a 100% acicular ferrite that is a microestructure of a high strenght steel, evidenced the effect of the dilution of the tube chemistry in the weld metal.
40
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal

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