Damage

8 cases · 83 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Microstructure: Bainite Capture method: Optical Microscope clear all

Damage — sub-branches

Corrosion 1Fabrication Defect 5High Temperature 1Hydrogen 1

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The tube microstructure is ferritic-pearlitic, typical of this kind of material. No evidences of microstrutural changes were detected (no overheating, no decarburization).
177
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of the thermal spray (TS) layer showing the different alloys, gray oxides and black voids. The Ni base TS alloy is of a yellow colour at the interface with the shaft substrate (in the left). The Cr base TS alloy appears white, similar to the shaft substrate. Longitudinal section of the shaft.
42
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - As polished micrographyDf - Coating Layer
Micrographic detail of the longitudinal section of the tube, close to the external surface. The carburizing layer consists of a bainitic structure, with intergranular and intragranular carbide precipitation.
1185
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - Nital Etched Micrography by OMDf - Carburized Layer
Micrography of a longitudinal section of the pin, in the center. The low carbon content of the steel in the center of the pin makes the structure bainitic even though it was quenched and tempered after carburizing.
80
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrography of the welded joint fusion line presenting the liquation cracking. The weld metal is in the right side (bottom) and the forged connector heat affected zone is in the left side (top).
83
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracking
Micrography of the ferritic low carbon steel plate (8 mm superior plate).
80
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal
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
Micrography of a longitudinal section of the mooring chain in the base metal. The low magnification reveals the banded structure of the rolled bar. The base metal microstructure is bainitic..
79
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Banded Structure

More from these cases

ML00163 — Corrosion Fatigue of a Boiler Waterwall TubeM - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
The internal side of the tube presented multiple cracks, filled with oxides, blunt-tipped, typical of a corrosion fatigue cracking mechanism.
160
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - As polished micrographyDf - Parallel cracks
Micrographic detail of the corrosion cracking from internal side of the tube, in several points at the tube surface.
156
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - As polished micrographyDf - Corrosion Cracking
Low magnification micrography of the multiple cracks, parallel, transgranular. No evidences of microstrutural changes (heat evolution or decarburization).
127
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Transgranular Cracking
Micrography presenting the internal tube surface with several parallel cracks, some still in the beginning (less than 0.1 mm deep).
115
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Parallel cracks
Micrography of the crack tip, initiated from the internal tube surface. The crack is transgranular, filled with oxides and blunt-tipped.
109
VIEW
ML00163 / Jun.2020
Corrosion Fatigue of a Boiler Waterwall Tube
M - Low Carbon SteelP - Seamless tubeAp - BoilerCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Transgranular Cracking

+9 more from this case →

ML00108 — Thermal Spray Layer in a Pinion ShaftM - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Micrographic detail, as polished in a longitudinal section, of the interface between the shaft substrate and the thermal spray layer. In the left it is the shaft substrate also presenting parts of aligned inclusions (gray). In the center it is the Ni base TS alloy and in the right it is the Cr base TS alloy. There are also black voids and grey oxides.
33
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - As polished micrographyDf - Coating Layer
Micrography of the interface between the shaft surface and the thermal spray layer. The shaft steel presents a quenched and tempered structure. Longitudinal section.
32
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Coating Layer
Micrographic detail of the interface between the shaft surface and the thermal spray layer. The shaft steel presents a quenched and tempered structure. Longitudinal section.
33
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Coating Layer
Micrographic detail of the interface between the shaft surface and the thermal spray layer. The shaft steel presents a quenched and (over) tempered structure. Longitudinal section.
35
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Coating Layer
Shaft microstructure in the longitudinal section, showing aligned segregations typical of the material forming.
31
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Longitudinal Section

+4 more from this case →

ML00107 — Carburized 9Cr1MoV Superheater TubeM - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Micrography of the longitudinal section of the tube, close to the internal surface. A thick scale is evident, but no microstructural changes compared to the center of the tube.
183
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the tube in the center of the thickness, showing a ferritic-bainitic structure of this CrMoV steel.
156
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the tube in the center of the thickness, showing a ferritic-bainitic structure of this CrMoV steel.
137
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the tube in the center of the thickness, showing a ferritic-bainitic structure of this CrMoV steel.
142
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of the longitudinal section of the tube, close to the external surface, presenting a thick deposit.
110
VIEW
ML00107 / Dec.2017
Carburized 9Cr1MoV Superheater Tube
M - Heat Resistant SteelP - Seamless tubeAp - BoilerCd - Carburization
Cm - As polished micrographyDf - Close to the External Surface

+7 more from this case →

ML00081 — Hydrogen Cracking of a Chromium Plated Carburized PinM - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Micrographic detail of the bainitic structure in the center of the pin, that was quenched and tempered after carburizing.
75
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the pin, at the surface. The pin was carburized, quenched and tempered (yellow diffuse layer at the surface, 0.5 mm of extension) and a white layer of hard chromium plating is evident.
108
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Carburized Layer
Micrographic detail a longitudinal section of the pin, at the surface, showing the case hardened. The pin carburized, quenched and tempered structure presents a gradient of carbon content and consequently a gradient of martensitic structure and hardness. Close to the surface the hardness level is 742 HV1 .
87
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - At the Surface
Micrographic detail of the high hardness martensitic structure at the surface of the pin, that was quenched and tempered after carburizing.
67
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Martensite
Micrography that presents a secondary cracking (adjacent to the broken surface) propagating 500 microns from the surface, where there is a white layer of hard chromium .
78
VIEW
ML00081 / Aug.2017
Hydrogen Cracking of a Chromium Plated Carburized Pin
M - Low Alloy for Thermochemical TreatmentP - Chromium PlatedAp - AutomotiveCd - Hydrogen Embrittlement
Cm - Nital Etched Micrography by OMDf - Carburized Layer

+3 more from this case →

ML00072 — Liquation Cracks in a High Strength JointM - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
The liquation crack is a hot crack in the base metal (at the HAZ) that induces a solidification crack in the weld metal.
66
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrographic detail of the cracks at the fusion line of the welded joint, at the connector side. The cracking presents morphology of melting regions of impurities at grain boundaries of the large grains of the heat affected zone (HAZ).
57
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Fusion Line
The HAZ presents microcracks at previous austenite grain boundaries. These regions melted during welding and generated cracks associated to low melting temperature phases.
48
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Microcracks
The HAZ presents microcracks at previous austenite grain boundaries. These regions melted during welding and generated cracks associated to low melting temperature phases.
43
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Microcracks
Micrography of the AISI 4130 forging, 5/8" thickness, close to the welded region, in the longitudinal section.
42
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal Left Side

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ML00069 — Liquation Cracks in SAW of Low Carbon SteelM - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Micrographic detail of the ferritic low carbon steel plate (8 mm superior plate).
80
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrographic detail of the weld metal presenting a typical low carbon steel structure (acicular ferrite and previous austenite grain boundary ferrite).
78
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrographic detail of the weld metal presenting a typical low carbon steel structure (acicular ferrite and previous austenite grain boundary ferrite).
72
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrography of the fracture at the superior plate (8 mm thickness). The fracture occurred in the coarse grain heat affected zone.
60
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Fracture
Micrography of the fracture at the fillet weld margin. The fracture occurred in the coarse grain heat affected zone of the superior plate (8 mm thickness).
54
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Fracture

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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

+1 more from this case →

ML00013 — Welding Cracks in Mooring ChainM - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Micrographic detail of the bainitic microstructure of the base metal in the longitudinal section.
72
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the mooring chain at the flash welded region. The banded structure is deformed by the upset, close to the weld metal that is ferritic-bainitic.
61
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Bainitic Ferrite
Micrographic detail of the ferritic-bainitic weld metal, autogenous flash butt weld.
56
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Bainitic Ferrite
Welded region etched to reveal impurities. The banded structure creates a continuous network parallel to the weld metal.
50
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Micro by OM, picric acid+FeCl3+H2O etchDf - Segregated Regions
Micrography of a longitudinal section of the mooring chain, at the main crack position. The crack follows a network of segregations.
48
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Segregated Regions

+1 more from this case →