Low Carbon Steel

6 cases · 100 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

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Aspect before cleaning of the heavy U bolt pipe clamp, 38 mm diameter wire, at the fractured position. It is possible to see that it broke in a region where the clamp was no longer coated and there is no insert in the groove (at the internal clamp diameter). The fracture is transverse to the clamp axis.
522
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Aspect Before AnalysisDf - General View
Aspect of a transverse section of the 4" pipe showing the barnacles adhered to the internal pipe surface, and the leakage position (in the top of the figure). It is possible to see that the deposits are attached all throught the internal pipe perimeter but the damage is localized. The damage morphology suggests it is a crack, or a welding defect, but the microstructural analysis indicated that the damage is a galvanic effect at the autogenous seam weld.
1135
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Longitudinal Section AspectDf - Localized Corrosion
Multiple thermal fatigue cracks at the welded joint between the smoke tube (vertical, internal diameter 248mm) and the tubesheet (horizontal, plate of 22 mm thickness). This is a view from the combustion chamber. The dye check tests revealed several parallel cracks.
1249
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - Aspect by NDTDf - Thermal Fatigue Cracks
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
Bimetallic engine bearing, removed from service at the end of its life.
356
VIEW
ML00083 / Oct.2017
Steel Back of a Bimetallic Engine Bearing
M - Low Carbon SteelP - Cold FormedAp - ShipCd - Removed From Service
Cm - Aspect Before AnalysisDf - General View
Ferritic-perlitic microstructure of a longitudinal section of the plate that was qualified to be adopted in a tubesheet boiler. Hot formed plate presenting perlite banding.
659
VIEW
ML00031 / Jan.2017
Carbon Steel Tubesheet for Boiler
M - Low Carbon SteelP - Rolled PlateAp - ShipCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite

More from these cases

ML00171 — Corrosion Fatigue of U Bolt Pipe ClampM - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Aspect of the U bolt clamp with partial detachment of the coating (white brown) in a region where the polimeric insert (dirty white) is still in the wire groove at the internal clamp diameter (ID).
91
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Aspect Before AnalysisDf - General View
Detailed aspect of the fractured position, in a region where the clamp was no longer coated and there is no insert in the groove (at the internal clamp diameter). The fracture is transverse to the clamp axis.
86
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Aspect Before AnalysisDf - Fracture
Same aspect of the previous image after cleaning, showing a subcritical propagation aspect (fatigue), starting at the groove (ID) and also at the clamp surface in the OD.
75
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Aspect Before AnalysisDf - Fracture
In the region where the polimeric insert was loose, the protective coating of the clamp has suffered detachment.
69
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Aspect Before AnalysisDf - Layer Detachment
Close to the ID of the clamp, at the groove position, there are cracks in the coating (white brown) and also at the substrate.
63
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Aspect Before AnalysisDf - Cracks

+22 more from this case →

ML00140 — Preferential Corrosion of Pipe Seam WeldM - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Micrography of the pipe transverse section presenting a granular microstructure.
147
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Transverse Section
Micrography of the pipe transverse section presenting a predominatly ferritic-perlitic microstructure.
132
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the predominatly ferritic-perlitic microstructure. Pipe transverse section.
95
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Aspect of the 4" pipe that was in seawater service for 8 years and leaked in a longitudinal line that corresponds to the seam weld. The internal surface presented thick deposits. Although the pipe was cut with a thermal process, the analysis was conducted after mechanical cutting.
100
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Aspect Before AnalysisDf - General View
Detail of the transverse section of the 4" pipe at the longitudinal seam weld evidencing the leakage position. The damage appears as a through wall opening. The pipe thickness is 8 mm and there are no evidences of general corrosion (the SCH 80 corresponds to 8.6 mm) or pitting at the internal surface.
100
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Transverse Section AspectDf - Leakage

+19 more from this case →

ML00119 — Thermal Fatigue of a Marine BoilerM - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Macrography of the plate (thickness 22mm, in horizontal position) to tube (thickness 12.5 mm, in vertical position) welded joint. The half V groove was welded from the top (position inside the combustion chamber) in five weld beads, and with a small fillet welded from the water side (ouside of the tube). Average hardness of the plate is 180HV1 (1kg), of the tube is 150HV1 and of the weld is 190HV1. Maximum hardness of the tube HAZ is 165HV1 and plate HAZ is 195HV1.
219
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - NItal Etched MacroDf - Welded Joint
Micrography of the plate in a longitudinal section, presenting a typical ferritic pearlitic structure, banded. The plate is 22 mm thick.
182
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Banded Structure
Micrography of the plate in a longitudinal section, presenting a typical ferritic pearlitic structure, banded.
165
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrographic detail of the ferritic pearlitic structure of the plate in the longitudinal section.
147
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Micrography of the weld metal in the center os the weld. Columnar grains (of the previous austenite) with primary ferrite in the grain boundaries; ferrite with aligned second phases and acicular ferrite, intragranular.
137
VIEW
ML00119 / Feb.2018
Thermal Fatigue of a Marine Boiler
M - Low Carbon SteelP - Fabrication WeldAp - ShipCd - Thermal Fatigue
Cm - Nital Etched Micrography by OMDf - Weld Metal

+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).
134
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.
98
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.
107
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 →

ML00083 — Steel Back of a Bimetallic Engine BearingM - Low Carbon SteelP - Cold FormedAp - ShipCd - Removed From Service
Micrography of a transverse section of the engine bearing, close to the internal surface, showing two layers of bearing alloys that presents a total thickness of 600 microns.
29
VIEW
ML00083 / Oct.2017
Steel Back of a Bimetallic Engine Bearing
M - Low Carbon SteelP - Cold FormedAp - ShipCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Surface Layer
Micrographic detail of a transverse section of the back steel of an engine bearing, presenting a predominantly ferritic structure, strain hardened.
26
VIEW
ML00083 / Oct.2017
Steel Back of a Bimetallic Engine Bearing
M - Low Carbon SteelP - Cold FormedAp - ShipCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Predominantly Ferritic
Micrography of a transverse section of the back steel of an engine bearing, presenting a predominantly ferritic structure, strain hardened.
24
VIEW
ML00083 / Oct.2017
Steel Back of a Bimetallic Engine Bearing
M - Low Carbon SteelP - Cold FormedAp - ShipCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Strain Hardened
Micrography of a transverse section of the back steel of an engine bearing, presenting a predominantly ferritic structure, strain hardened.
24
VIEW
ML00083 / Oct.2017
Steel Back of a Bimetallic Engine Bearing
M - Low Carbon SteelP - Cold FormedAp - ShipCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Strain Hardened
ML00031 — Carbon Steel Tubesheet for BoilerM - Low Carbon SteelP - Rolled PlateAp - ShipCd - Typical manufacturing
Ferritic-perlitic microstructure of a longitudinal section of the plate that was qualified to be adopted in a tubesheet boiler. Hot formed plate presenting perlite banding.
213
VIEW
ML00031 / Jan.2017
Carbon Steel Tubesheet for Boiler
M - Low Carbon SteelP - Rolled PlateAp - ShipCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Ferritic-perlitic microstructure of a longitudinal section of the plate that was qualified to be adopted in a tubesheet boiler. Hot formed plate presenting perlite banding.
173
VIEW
ML00031 / Jan.2017
Carbon Steel Tubesheet for Boiler
M - Low Carbon SteelP - Rolled PlateAp - ShipCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Banded Pearlite