Oxalic Acid Electrolytic Etch

9 cases · 68 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Microstructure: Austenite clear all

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Sample surface. Microstructure of the plate base metal, exposed to high temperature exhausting gases. Refined austenite and some cracks.
24
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Oxalic Acid Electrolytic EtchDf - Base Metal
The stub end was manufactured from a plate and the microstructure in a longitudial section shows a refined granular austenitic structure.
62
VIEW
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Longitudinal Section
Micrography of a longitudinal section of the tubing showing a granular structure, austenitic.
52
VIEW
ML00167 / Aug.2020
Fatigue of a Flared Tubing Connection
M - Austenitic Stainless SteelP - TubingAp - EngineCd - Mechanical Fatigue
Cm - Oxalic Acid Electrolytic EtchDf - Longitudinal Section
Micrography of a longitudinal section, in the center of the valve body, solid 3" thickness. The structure is austenitic with delta ferrite in interdendritic spaces.
67
VIEW
ML00164 / Jun.2020
Austenitic SS Casting for Valve Body
M - Austenitic Stainless SteelP - CastingAp - ValveCd - Typical manufacturing
Cm - Oxalic Acid Electrolytic EtchDf - Austenite
SAMPLE 1 AT THE FRACTURE - Micrography in low magnification where the thickness is reduced to zero (fracture). Side A (process side) to the bottom and side B (furnace environment side) to the top.
85
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - Oxalic Acid Electrolytic EtchDf - Low Mag
Optical micrography of a longitudinal section of the fractured bolt, at the thread. The material is austenitic, free from carbides, and the threads were almost removed by the stress corrosion cracks.
756
VIEW
ML00157 / Feb.2020
Bolts Under Chloride SCC Conditions
M - Austenitic Stainless SteelP - BoltAp - Oil and GasCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Stress Corrosion Cracks
Optical micrography of the transverse section of the drill collar, in the center of the thickness, presenting an uniform, granular, fully austenitic microstructure.
76
VIEW
ML00135 / May.2018
MIC of a Non Magnetic Drilling Tool
M - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Transverse Section
Image by scanning electron microscopy of the metallurgically bonded interface of the internally cladded pipe. It is a longitudinal seam welded pipe, with substrate in low alloy steel X65 and clad plate in Alloy 625 (welded by a solid state process). The region is a detail in the side of the Ni alloy clad plate where a grain refinement has occurred probably due to recrystallization of a strain hardened region during later heat treatment. The microhardness of this region is a lot higher than the value obtained out of this region, in the clad plate.
904
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Oxalic Acid Electrolytic EtchDf - Clad Interface

More from these cases

ML00174 — Carburization of a 347 SS Welded JointM - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Detailed microstructure of the plate base metal, exposed to high temperature exhausting gases. Refined austenite, precipitation of carbides in the grain boumdaries and some cracks.
23
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Oxalic Acid Electrolytic EtchDf - Austenite
Detailed microstructure of the plate base metal, exposed to high temperature exhausting gases. Refined austenite, precipitation of carbides in the grain boumdaries and some cracks.
24
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Oxalic Acid Electrolytic EtchDf - Crack
Sample surface. Microstructure of the weld metal, exposed to high temperature exhausting gases. Austeno-ferritic structure and some cracks.
20
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Oxalic Acid Electrolytic EtchDf - Weld Metal
Detailed microstructure of the weld metal, exposed to high temperature exhausting gases. Austeno-ferritic structure and some cracks.
21
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Oxalic Acid Electrolytic EtchDf - Ferrite and Austenite
Detailed microstructure of the weld metal, exposed to high temperature exhausting gases. Austeno-ferritic structure, strong carbide precipitation integranular and transgranular, and some cracks.
23
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Oxalic Acid Electrolytic EtchDf - Cracks

+3 more from this case →

ML00168 — SCC of Austenitic SS Flange Stub EndM - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Micrography of a longitudinal section of the stub end showing a refined austenitic structure.
57
VIEW
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Austenite
Micrographic detail of the austenitic structure. Free from grain boundaries carbide precipitation.
53
VIEW
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Austenite
Micrography of the stub end close to the external surface, outer diameter in the top of the image, presenting multiple cracks starting fro the surface and propagating into the thickness, through wall.
32
VIEW
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Close to the External Surface
Micrography of the stub end in the middle of the thickness, outer diameter to the top of the image, presenting multiple branched cracks.
26
VIEW
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - In the Center of the Thickness
Micrography of the stub end longitudinal section, showing multiple branched transgranular cracks.
25
VIEW
ML00168 / Aug.2020
SCC of Austenitic SS Flange Stub End
M - Austenitic Stainless SteelP - Stub EndAp - Chemical IndustryCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Transgranular Cracking

+2 more from this case →

ML00167 — Fatigue of a Flared Tubing ConnectionM - Austenitic Stainless SteelP - TubingAp - EngineCd - Mechanical Fatigue
Micrography of a longitudinal section of the tubing, showing the austenitic structure free from strain hardening and free from grain boundary carbides.
51
VIEW
ML00167 / Aug.2020
Fatigue of a Flared Tubing Connection
M - Austenitic Stainless SteelP - TubingAp - EngineCd - Mechanical Fatigue
Cm - Oxalic Acid Electrolytic EtchDf - Austenite
Micrographic detail of the austenitic structure, free from strain hardening and free from grain boundary carbides.
54
VIEW
ML00167 / Aug.2020
Fatigue of a Flared Tubing Connection
M - Austenitic Stainless SteelP - TubingAp - EngineCd - Mechanical Fatigue
Cm - Oxalic Acid Electrolytic EtchDf - Austenite
Micrography of a longitudinal section of the tubing where the fracture occurred. the left side is the outer diameter and the right side is the inner diameter.
37
VIEW
ML00167 / Aug.2020
Fatigue of a Flared Tubing Connection
M - Austenitic Stainless SteelP - TubingAp - EngineCd - Mechanical Fatigue
Cm - Oxalic Acid Electrolytic EtchDf - At the Surface
Micrography of a longitudinal section of the flared tubing where the fracture occurred. The starting point of the fracture is associated to the external side of the tubing, where it was connected by a nut and there was a localized plastic deformation due to the fitting assembly.
33
VIEW
ML00167 / Aug.2020
Fatigue of a Flared Tubing Connection
M - Austenitic Stainless SteelP - TubingAp - EngineCd - Mechanical Fatigue
Cm - Oxalic Acid Electrolytic EtchDf - Transgranular Fracture
Micrographic detail of the localized plastic deformation due to the fitting assembly, in the region where the fatigue has started.
30
VIEW
ML00167 / Aug.2020
Fatigue of a Flared Tubing Connection
M - Austenitic Stainless SteelP - TubingAp - EngineCd - Mechanical Fatigue
Cm - Oxalic Acid Electrolytic EtchDf - Plastic Deformation
ML00164 — Austenitic SS Casting for Valve BodyM - Austenitic Stainless SteelP - CastingAp - ValveCd - Typical manufacturing
Micrography of a longitudinal section, in the center of the valve body. The structure is austenitic with delta ferrite in interdendritic spaces. The austenite presents a cored matrix in the dendrites, indicating the chemical composition was not homogeneized during the heat treatment.
60
VIEW
ML00164 / Jun.2020
Austenitic SS Casting for Valve Body
M - Austenitic Stainless SteelP - CastingAp - ValveCd - Typical manufacturing
Cm - Oxalic Acid Electrolytic EtchDf - Delta ferrite
Micrographic detail of the cored austenitic structure with delta ferrite in interdendritic spaces. The chemical composition was not homogeneized during the heat treatment.
55
VIEW
ML00164 / Jun.2020
Austenitic SS Casting for Valve Body
M - Austenitic Stainless SteelP - CastingAp - ValveCd - Typical manufacturing
Cm - Oxalic Acid Electrolytic EtchDf - Delta ferrite
Micrography of a longitudinal section, in the 1" thickness valve wall. The structure is austenitic with delta ferrite in interdendritic spaces.
48
VIEW
ML00164 / Jun.2020
Austenitic SS Casting for Valve Body
M - Austenitic Stainless SteelP - CastingAp - ValveCd - Typical manufacturing
Cm - Oxalic Acid Electrolytic EtchDf - Austenite
Micrography of a longitudinal section, in the valve wall 1" thick. The structure is austenitic with delta ferrite in interdendritic spaces. The austenite is clean indicating that the homogeneization of a smaller thickness in the heat treatment is considered effective.
40
VIEW
ML00164 / Jun.2020
Austenitic SS Casting for Valve Body
M - Austenitic Stainless SteelP - CastingAp - ValveCd - Typical manufacturing
Cm - Oxalic Acid Electrolytic EtchDf - Delta ferrite
Micrographic detail of the clean austenitic matrix, with delta ferrite in interdendritic spaces.
35
VIEW
ML00164 / Jun.2020
Austenitic SS Casting for Valve Body
M - Austenitic Stainless SteelP - CastingAp - ValveCd - Typical manufacturing
Cm - Oxalic Acid Electrolytic EtchDf - Delta ferrite
ML00160 — High Temperature Degradation of 310SSM - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
SAMPLE 1 AT THE FRACTURE - Micrography at the position where the thickness is reduced to zero. Side A to the bottom. The microstructure is austenite with intergranular and transgranular precipitation. The position of the zero thickness presents aspect of an intergranular fracture, and in side A there are several intergranular cracks from the surface.
83
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - Oxalic Acid Electrolytic EtchDf - Austenitic with Secondary Precipitation
SAMPLE 1 AT THE FRACTURE - Micrographic detail of the intergranular fracture. The austenitic grains of the material are loosing.
80
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - Oxalic Acid Electrolytic EtchDf - Intergranular Fracture
SAMPLE 1 AT 1 mm THICKNESS - Micrography in low magnification in the center of the thickness. The microstructure is austenitic with secondary intergranular and intragranular precipitation.
76
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - Oxalic Acid Electrolytic EtchDf - Low Mag
SAMPLE 1 AT 1 mm THICKNESS - Micrography in the center of the thickness. The microstructure is austenitic with secondary precipitation, intergranular and intragranular.
76
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - Oxalic Acid Electrolytic EtchDf - Austenitic with Secondary Precipitation
SAMPLE 1 AT 1 mm THICKNESS - Micrographic detail of the austenite with secondary precipitation. This oxalic acid electrolytic etch is revealing the integranular and transgranular (or intragranular) precipitation. In the grain boundaries it is possible to see: 1) a continuous network of carbide precipitation and 2) isolated islands of sigma phase. In the middle of the grains there are rounded and neddles like carbides.
72
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - Oxalic Acid Electrolytic EtchDf - Austenitic with Secondary Precipitation

+5 more from this case →

ML00157 — Bolts Under Chloride SCC ConditionsM - Austenitic Stainless SteelP - BoltAp - Oil and GasCd - Stress Corrosion
Low magnification micrography, by optical microscope, of the longitudinal section of a damaged bolt, in the center of the thickness. The microstructure is austenitic, free from carbides.
100
VIEW
ML00157 / Feb.2020
Bolts Under Chloride SCC Conditions
M - Austenitic Stainless SteelP - BoltAp - Oil and GasCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Austenite
Detail of the strain hardened austenitic microstructure. Micrography by optical microscope, of the longitudinal section of a bolt, in the center of the thickness.
76
VIEW
ML00157 / Feb.2020
Bolts Under Chloride SCC Conditions
M - Austenitic Stainless SteelP - BoltAp - Oil and GasCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Strain Hardened
Optical micrography of a longitudinal section of the fractured bolt, at the thread. The material is austenitic, free from carbides, and the threads were fully cracked by the stress corrosion mechanism.
58
VIEW
ML00157 / Feb.2020
Bolts Under Chloride SCC Conditions
M - Austenitic Stainless SteelP - BoltAp - Oil and GasCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Stress Corrosion Cracks
Optical micrography of a longitudinal section of the fractured bolt, under the thread, showing stress corrosion cracks through the section.
46
VIEW
ML00157 / Feb.2020
Bolts Under Chloride SCC Conditions
M - Austenitic Stainless SteelP - BoltAp - Oil and GasCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Stress Corrosion Cracks
Detailed aspect of the stress corrosion cracks in a longitudinal section of the fractured bolt, under the thread. The microstructure is strain hardened austenite.
47
VIEW
ML00157 / Feb.2020
Bolts Under Chloride SCC Conditions
M - Austenitic Stainless SteelP - BoltAp - Oil and GasCd - Stress Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Stress Corrosion Cracks

+1 more from this case →

ML00135 — MIC of a Non Magnetic Drilling ToolM - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Optical micrography of the transverse section of the drill collar, in the center of the thickness, presenting an uniform, granular, fully austenitic microstructure.
64
VIEW
ML00135 / May.2018
MIC of a Non Magnetic Drilling Tool
M - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Transverse Section
Micrographic detail of the transverse section of the drill collar, in the center of the thickness, presenting an uniform, granular, fully austenitic microstructure.
61
VIEW
ML00135 / May.2018
MIC of a Non Magnetic Drilling Tool
M - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Austenite
Optical micrography of the longitudinal section of the drill collar, in the center of the thickness, presenting slightly elongated grains of fully austenitic microstructure, cold worked. The material presented 38HRc hardness.
57
VIEW
ML00135 / May.2018
MIC of a Non Magnetic Drilling Tool
M - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Longitudinal Section
Optical micrography of the longitudinal section of the drill collar, in the center of the thickness, presenting slightly elongated grains of fully austenitic microstructure, cold worked.
62
VIEW
ML00135 / May.2018
MIC of a Non Magnetic Drilling Tool
M - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Longitudinal Section
Micrographic detail of the longitudinal section of the drill collar, in the center of the thickness, presenting slightly elongated grains of fully austenitic microstructure, cold worked.
59
VIEW
ML00135 / May.2018
MIC of a Non Magnetic Drilling Tool
M - High Mn Austenitic SteelP - Tubular ForgingAp - O&G Well DrillingCd - Pitting Corrosion
Cm - Oxalic Acid Electrolytic EtchDf - Austenite

+6 more from this case →

ML00133 — Seam Welded Pipe Cladded with Alloy 625M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Micrography of a longitudinal section of the pipe at the interface,with oxalic acid electrolytic method that overetchs the low alloy steel structure (to the left side of the image), and reveals the structure of the clad plate interface, different at the position where it was metallurgically bonded to the the pipe (when it was still a low alloy plate - X65).
36
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Oxalic Acid Electrolytic EtchDf - Clad Interface
Micrography of the metallurgically bonded interface of the internally cladded pipe. The region is a detail in the side of the Ni alloy clad plate where a grain refinement has occurred probably due to recrystallization of a strain hardened region during later heat treatment.
35
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Oxalic Acid Electrolytic EtchDf - Clad Interface
Micrographic detail of the metallurgically bonded interface of the internally cladded pipe. The region is a detail in the side of the Ni alloy clad plate where a grain refinement has occurred probably due to recrystallization of a strain hardened region during later heat treatment. The microhardness very close to the interface (429 HV100g) is higher than the value of 358HV 100g ,obtained 0.2mm far from this region in the clad plate .
37
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Oxalic Acid Electrolytic EtchDf - Clad Interface
Image by scanning electron microscopy of the metallurgically bonded interface of the internally cladded pipe. It is a longitudinal seam welded pipe, with substrate in low alloy steel X65 and clad plate in Alloy 625 (welded by a solid state process). The region is a detail in the side of the Ni alloy clad plate where a grain refinement has occurred probably due to recrystallization of a strain hardened region during later heat treatment. The microhardness of this region is a lot higher than the value obtained out of this region, in the clad plate.
28
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Oxalic Acid Electrolytic EtchDf - Clad Interface
Image by scanning electron microscopy of the metallurgically bonded interface of the internally cladded pipe. It is a longitudinal seam welded pipe, with substrate in low alloy steel X65 and clad plate in Alloy 625 (welded by a solid state process). The region is a detail in the side of the Ni alloy clad plate where a grain refinement has occurred probably due to recrystallization of a strain hardened region during later heat treatment. The microhardness of this region is a lot higher than the value obtained out of this region, in the clad plate.
26
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Oxalic Acid Electrolytic EtchDf - Grain refined structure