Low Carbon Steel

13 cases · 177 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Standard: ASTM clear all

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The location of the threaded fitting started leaking after less than five years in service. Although the corrosion rate was not high, the localized material loss in the threaded surface of the carbon steel flange allowed the connection leakage.
769
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Aspect Before AnalysisDf - General View
Gas piping. Aspect of a branching line 2" ND, lateral to a horizontal main pipe ND 8", welded using a weldolet. The cracking started at the margin of the weld in the upper part of the pipe, where the weld crossed the longitudinal direction of the pipe, perpendicular to the branch.
932
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Aspect Before AnalysisDf - Cracking
Red painted device where the 50 mm x 50 mm carbon steel plate was positioned (in the circle). The image presents the target, positioned 100 meters far from the gun, after the shot and the projectile perforated the plate, as will be presented in the other figures.
602
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Aspect Before AnalysisDf - General View
Micrography of a transverse section of the pipe, external diameter 33.4 mm schedule XXS, in the center of the 9.1 mm thickness. The structure is predominantly ferritic. Small amount of pearlite.
553
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Predominantly Ferritic
Micrography of a transverse section of the pipe, external diameter 26.7 mm, in the center of the 7.85mm thickness. Refined structure but not uniform. Ferrite and pearlite.
512
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the ferritic-pearlitic structure of the angle L shape, equal legs, in the transverse section.
467
VIEW
ML00035 / Dec.2017
Carbon Steel L Shape
M - Low Carbon SteelP - Rolled ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
The micrography of the longitudinal section of the tube, close to OD, shows the paralel cracks, filled with oxides, perpendicular to the surface.
1441
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Close to the External Surface
The hose connector fracture surface presented different fracture micromechanisms associated to the microstructure: inclusion decohesion, small regions of intergranular fractures (probably due to cementite at grain boundaries), and cleavage of the ferritic structure. All these mechanisms are brittle.
560
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Fractography by SEMDf - Brittle Fracture

More from these cases

ML00184 — Dissimilar Steels in a Threaded ConnectionM - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
The painting of the valve body was detaching at the vent location where the fitting was installed, not fully tighted. Three threaded fillets were outside of the body.
190
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Aspect After CleaningDf - Painting Detachment
The austenitic stainless steel fitting was removed from the valve body and presented the sdhesion of oily deposits.
150
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Aspect Before AnalysisDf - Surface Deposits
The cleaned fitting is sound. No corrosion, only surface stains.
121
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Aspect After CleaningDf - General View
The threads of the carbon steel valve body is corroded. The offshore ambient is wet and chloride rich, creating an aggressive environment for the carbon steel threads.
99
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Surface AspectDf - Corrosion
Not only the threads were corroded but all regions under the painting that was detached from the surface.
86
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Surface AspectDf - Corrosion

+8 more from this case →

ML00149 — Vibration Induced Fatigue in a Gas PipingM - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Gas piping. Aspect of a branching line 2" ND with a flange, lateral to a main pipe ND 8", welded using a weldolet. The cracking is at the margin of the weld.
115
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Aspect Before AnalysisDf - General View
Micrography of a transverse section of the seamless pipe, presenting a ferritic-pearlitic structure.
84
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of a transverse section of the seamless pipe, presenting a ferritic-pearlitic structure.
70
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Gas piping. Aspect of a branching line 2" ND, lateral to a horizontal main pipe ND 8", welded using a weldolet. In the lower part of the branch there are no cracks.
61
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Aspect Before AnalysisDf - Welded Joint
Aspect of the brach line viewed from the internal side of the main pipe, after cuting. It is possible to see that the pipe was perforated by a thermal cutting (looking the finishing aspect of the edge of the hole). The weldolet was welded only from the external side of the pipe.
62
VIEW
ML00149 / Dec.2018
Vibration Induced Fatigue in a Gas Piping
M - Low Carbon SteelP - Piping spoolAp - FPSOCd - Vibration Induced Fatigue
Cm - Aspect Before AnalysisDf - Internal Surface

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ML00143 — Impact of a .308 Winchester on A36 PlateM - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Aspect of a typical .308 Winchester projectile, similar to the one adopted to shot the plate, cut in a longitudinal section. It is a Cu alloy case filled with Pb-Sb.
92
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Longitudinal Section AspectDf - Longitudinal Section
Aspect of the 3/8" thickness plate, 50 mm x 50 mm, of the low carbon steel steel, in the face of impact with the projectile. The plate was perforated by the bullet.
88
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Aspect Before AnalysisDf - General View
Micrography of the plate in a section, showing a ferritic-pearlitic microstructure in the middle of the thickness.
84
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of the plate in a section, showing a ferritic-pearlitic microstructure in the middle of the thickness, in a position where the plate was not affected by the shot.
65
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the plate in a section, showing a ferritic-pearlitic microstructure in the middle of the thickness.
66
VIEW
ML00143 / Aug.2018
Impact of a .308 Winchester on A36 Plate
M - Low Carbon SteelP - Rolled PlateAp - StructureCd - Pierced
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite

+51 more from this case →

ML00112 — 1" XXS Pipe Not Qualified For Low TempM - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Micrography of a transverse section of the pipe, close to the external surface (OD). The pipe presented a predominatly ferritic structure.
43
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Micrography of a transverse section of the pipe, close to the external surface (OD). The pipe presented a 0.2 mm decarburized layer, fully ferritic.
35
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Micrography of a transverse section of the pipe, close to the external surface (OD). The pipe presented a predominatly ferritic structure.
31
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Predominantly Ferritic
Micrography of a transverse section of the pipe, close to the internal surface (ID). The pipe presented a predominatly ferritic structure.
29
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrography of a transverse section of the pipe, close to the internal surface (ID). The pipe presented a predominatly ferritic structure.
22
VIEW
ML00112 / Dec.2017
1" XXS Pipe Not Qualified For Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface

+2 more from this case →

ML00111 — 3/4" XXS Pipe Not Qualified for Low TempM - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Micrography of a transverse section of the pipe, close to the internal surface (ID). Refined structure. Ferrite and pearlite.
64
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrography of a transverse section of the pipe, close to the internal surface (ID). Refined structure, but not uniform. Ferrite and pearlite. The pearlite colonies appear in a network.
45
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrography of a transverse section of the pipe, close to the internal surface (ID). Refined structure. Ferrite and pearlite. The structure is not uniform. There is a large variation in the ferritic grain size and the pearlite colonies appear forming a network.
39
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of a transverse section of the pipe, close to the external surface (OD). Refined structure. Ferrite and pearlite.
33
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the External Surface
Micrography of a transverse section of the pipe, close to the external surface (OD). Refined structure. Ferrite and pearlite.
34
VIEW
ML00111 / Dec.2017
3/4" XXS Pipe Not Qualified for Low Temp
M - Low Carbon SteelP - Seamless PipeAp - RefineryCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Close to the External Surface

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ML00035 — Carbon Steel L ShapeM - Low Carbon SteelP - Rolled ShapeAp - StructureCd - Removed From Service
Micrography of the transverse section of the rolled shape presenting an aligned structure, ferritic-pearlitic. Transverse section.
97
VIEW
ML00035 / Dec.2017
Carbon Steel L Shape
M - Low Carbon SteelP - Rolled ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrography of the transverse section of the rolled shape presenting a ferritic-pearlitic microstructure. Transverse section, close to the surface.
80
VIEW
ML00035 / Dec.2017
Carbon Steel L Shape
M - Low Carbon SteelP - Rolled ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - At the Surface
Micrography of the transverse section of the rolled shape presenting an aligned structure, ferritic-pearlitic.
62
VIEW
ML00035 / Dec.2017
Carbon Steel L Shape
M - Low Carbon SteelP - Rolled ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Transverse Section
Micrography of the transverse section of the rolled shape presenting an aligned structure, ferritic-pearlitic, and long sulfide inclusions. Center of the leg of 12 mm thickness.
58
VIEW
ML00035 / Dec.2017
Carbon Steel L Shape
M - Low Carbon SteelP - Rolled ShapeAp - StructureCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Non Metallic Inclusions
ML00104 — Thermal Fatigue of a Boiler TubeM - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
The micrography of the longitudinal section of the tube, close to ID, shows the paralel cracks, filled with oxides, perpendicular to the surface.
229
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - As polished micrographyDf - Close to the Internal Surface
The water wall tube, external diameter 60.3mm and thickness 3.9 mm, shows circunferential cracks in the middle of the section. Several other tubes have failed after 10 years in service.
716
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Aspect Before AnalysisDf - General View
Aspect of the internal surface of the tube after longitudinal cut. This position is out of the damage area and only a small amount of deposits is evident.
216
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Surface AspectDf - Internal Surface
Aspect of the internal surface of the tube after longitudinal cut. This position is at the damage area where a thick deposit is evident.
186
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Surface AspectDf - Internal Surface
Aspect of the external surface of the tube, presenting a large circunferential crack.
171
VIEW
ML00104 / Dec.2017
Thermal Fatigue of a Boiler Tube
M - Low Carbon SteelP - Autogenously Welded TubeAp - BoilerCd - Thermal Fatigue
Cm - Surface AspectDf - External Surface

+16 more from this case →

ML00103 — Brittle Fracture of a Free-Cutting ConnectorM - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Aspect of the external side of the connector, with a longitudinally crack of a brittle aspect. It is a 5/8" connector (15.8 mm).
133
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - General View
Aspect of the internal side of the connector. The fracture, in the longitudinal direction, presents a brittle aspect. The thickness of the connector is about 2 mm.
126
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Brittle Fracture
Macroscopic detail of the brittle fracture, in the longitudinal direction.
105
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Brittle Fracture
Micrography of the longitudinal section of the fitiing, in a free-cutting steel. The microstructure is predominantly ferritic and there is a large amount of sulfide inclusions, aligned perpendicular to the forming direction.
97
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Micrographic detail of the longitudinal section of the fitiing, in a free-cutting steel. The microstructure is predominantly ferritic, with small perlitic areas and some free cementite at ferritic grain boundaries. There is a large amount of sulfide inclusions, aligned perpendicular to the forming direction.
106
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Non Metallic Inclusions

+11 more from this case →