Machined Part

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Crevice Corrosion in a Subsea System — Aspect Before Analysis

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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
Micrographic detail of the through wall cracking, slightly branched and thin.
656
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Cracking
Detail of the pin fracture surface, presenting both a flat aspect and a rough aspect in a shearing section of 2.5 mm width.
726
VIEW
ML00046 / Jan.2018
Brittle Fracture of SS Shear Pin
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Intergranular Cracking
Cm - Fractography by SEMDf - Fracture
Micrographic detail of the austenitic structure at the surface, where the grain size of the material increased. By optical microscopy the intragranular precipitation due to solution annealing and aging is not revealed.
794
VIEW
ML00089 / Sep.2017
Inconel 718 Allen Bolt for Subsea Application
M - NiCrFe AlloyP - Machined PartAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Austenite
Macrography of the welded joint upper part. Transverse section showing the different zones studied in this ML. See the schematic drawing in the next image.
454
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Kalling Etched MacroDf - Welded Joint
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
Regions of the pin thread presenting pitting corrosion.
635
VIEW
ML00016 / Apr.2017
SCC in Free Cutting 303SS
M - Austenitic Stainless SteelP - Machined PartAp - OffshoreCd - Stress Corrosion
Cm - Surface Aspect by SEMDf - Localized Corrosion
Longitudinal section of the fitting in the center of the thickness (2"). Refined ferritic structure.
370
VIEW
ML00030 / Jan.2017
Forging for High Pressure Application
M - Microalloyed SteelP - Machined PartAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Bainitic Ferrite

More from these cases

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 →

ML00093 — MIC of a Drilling ToolM - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
The tool housing ID 1 1/2" presented a longitudinal through wall cracking, in two positions at 180°. The internal side of the housing presented several pits.
66
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Through Wall Cracking
Micrography of a longitudinal section of the housing presenting a uniform tempered martensitic structure. The material presented a thickness about 2.5 mm in the region where the cracking started.
52
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Uniform Structure
Micrography of a longitudinal section of the housing presenting a uniform tempered martensitic structure.
51
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Aspect of the internal side of the housing presenting multiple cracks in longitudinal direction.
49
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Aspect Before AnalysisDf - Cracking
The microscopic aspect of the internal side of the housing evidences the characteristics of the multiple cracks, not directly related to pitting corrosion.
41
VIEW
ML00093 / Sep.2017
MIC of a Drilling Tool
M - Low Alloy Medium Carbon QTP - Heat Treated PartAp - O&G Well DrillingCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Cracks

+10 more from this case →

ML00046 — Brittle Fracture of SS Shear PinM - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Intergranular Cracking
Fracture appearance in a sheared region, presenting a ductile morphology for the fracture micromechanism.
109
VIEW
ML00046 / Jan.2018
Brittle Fracture of SS Shear Pin
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Intergranular Cracking
Cm - Fractography by SEMDf - Ductile Fracture
Fracture appearance in a brittle region, presenting an intergranular morphology.
93
VIEW
ML00046 / Jan.2018
Brittle Fracture of SS Shear Pin
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Intergranular Cracking
Cm - Fractography by SEMDf - Intergranular Cracking
Micrography of a longitudinal section of the pin, presenting a tempered martensitic structure with aligned delta ferrite and carbide phases.
80
VIEW
ML00046 / Jan.2018
Brittle Fracture of SS Shear Pin
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Intergranular Cracking
Cm - Kalling Etched Micrography by OMDf - Martensite, delta ferrite & carbides
Micrographic detail of the pin structure, in the longitudinal section, at the segregated band with aligned inclusions and phases, delta ferrite and carbides.
70
VIEW
ML00046 / Jan.2018
Brittle Fracture of SS Shear Pin
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Intergranular Cracking
Cm - Kalling Etched Micrography by OMDf - Martensite, delta ferrite & carbides
Micrographic detail of the pin structure, in the longitudinal section, presenting a martensitic matriz, aligned inclusions (grey, delta ferrite islands (poligonal white phases) and carbides (also white phases) surrounding the delta ferrite.
64
VIEW
ML00046 / Jan.2018
Brittle Fracture of SS Shear Pin
M - Martensitic Stainless SteelP - Machined PartAp - EnergyCd - Intergranular Cracking
Cm - Kalling Etched Micrography by OMDf - Martensite, delta ferrite & carbides

+1 more from this case →

ML00089 — Inconel 718 Allen Bolt for Subsea ApplicationM - NiCrFe AlloyP - Machined PartAp - SubseaCd - Typical manufacturing
The macrography shows the longitudinal section of the allen bolt, 1/2" nominal diameter, that was machined from a heat treated bar (solution annealed and aged). The granular structure presents differences in the grain sizes. At the bolt head (external surface of the original bar) the austenitic grain size is larger than in the center of the bar where the particles in segregated bands "arrested" the grains during hot forming and solution annealing.
58
VIEW
ML00089 / Sep.2017
Inconel 718 Allen Bolt for Subsea Application
M - NiCrFe AlloyP - Machined PartAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched MacroDf - Machined Thread
The micrography of a longitudinal section of the bolt close to the surface, at the thread, shows that it was machined from a bar, not rolled.
37
VIEW
ML00089 / Sep.2017
Inconel 718 Allen Bolt for Subsea Application
M - NiCrFe AlloyP - Machined PartAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Machined Thread
The micrography of a longitudinal section of the bolt, in the center of the thickness (ND 1/2"), shows an equiaxial granular structure. Although the material was hardened by heat treatment (solution annealing and aging), the microstructure at this magnification does not reveal the intragranular precipitation.
34
VIEW
ML00089 / Sep.2017
Inconel 718 Allen Bolt for Subsea Application
M - NiCrFe AlloyP - Machined PartAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched Micrography by OMDf - Equiaxial Grains
Micrographic detail of a longitudinal section of the bolt, in the center of the thickness (ND 1/2"). Although the material was hardened by heat treatment (solution annealing and aging), the microstructure observed by optical microscopy does not reveal the intragranular precipitation.
33
VIEW
ML00089 / Sep.2017
Inconel 718 Allen Bolt for Subsea Application
M - NiCrFe AlloyP - Machined PartAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched MacroDf - Austenite
The micrography of a longitudinal section, at the bolt head close to the surface of the original bar. In this region the material increased the grain size due to the lack of particles (inclusions), to "arrest" the grain boundaries (during hot forming and solution annealing). The smaller grain size is located in the center of the bar, that concentrated the inclusions.
30
VIEW
ML00089 / Sep.2017
Inconel 718 Allen Bolt for Subsea Application
M - NiCrFe AlloyP - Machined PartAp - SubseaCd - Typical manufacturing
Cm - Kalling Etched MacroDf - Dual grain sizes

+1 more from this case →

ML00045 — Subsea Tubular F6NM Martensitic SSM - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Schematic drawing presenting the different zones of the welded joint at the upper part.
49
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Identification drawingDf - Welded Joint
Macrography of the welded joint, at the root position, presenting the different zones studied in this ML. Transverse section. See the schematic drawing in the next image.
47
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Kalling Etched MacroDf - Welded Joint
Schematic drawing presenting the different zones of the welded joint
35
VIEW
ML00045 / Aug.2017
Subsea Tubular F6NM Martensitic SS
M - Martensitic Stainless SteelP - Fabrication WeldAp - OffshoreCd - Welding
Cm - Identification drawingDf - Welded Joint
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
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

+15 more from this case →

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
ML00016 — SCC in Free Cutting 303SSM - Austenitic Stainless SteelP - Machined PartAp - OffshoreCd - Stress Corrosion
Regions of the localized corrosion spots associated to non metallic inclusions.
123
VIEW
ML00016 / Apr.2017
SCC in Free Cutting 303SS
M - Austenitic Stainless SteelP - Machined PartAp - OffshoreCd - Stress Corrosion
Cm - Surface Aspect by SEMDf - Non Metallic Inclusions
The macrography of the longitudinal section of the pin (9.5 mm nominal diameter) shows the localized corrosion associated to the non metallic inclusions.
107
VIEW
ML00016 / Apr.2017
SCC in Free Cutting 303SS
M - Austenitic Stainless SteelP - Machined PartAp - OffshoreCd - Stress Corrosion
Cm - Macro Oxalic Acid Electrolytic EtchedDf - Localized Corrosion
The low magnification micrography of the longitudinal section of the pin shows the localized corrosion associated to the non metallic inclusions.
89
VIEW
ML00016 / Apr.2017
SCC in Free Cutting 303SS
M - Austenitic Stainless SteelP - Machined PartAp - OffshoreCd - Stress Corrosion
Cm - Micrography by OM using A262 Method ADf - Localized Corrosion
The pin microstructure in the longitudinal section shows austenitic structure, free from carbides, and sulfide inclusions that characterize the free cutting condition of this stainless steel.
77
VIEW
ML00016 / Apr.2017
SCC in Free Cutting 303SS
M - Austenitic Stainless SteelP - Machined PartAp - OffshoreCd - Stress Corrosion
Cm - Micrography by OM using A262 Method ADf - Non Metallic Inclusions
The micrographic detail of the longitudinal section of the pin shows the localized corrosion associated to the non metallic inclusions.
67
VIEW
ML00016 / Apr.2017
SCC in Free Cutting 303SS
M - Austenitic Stainless SteelP - Machined PartAp - OffshoreCd - Stress Corrosion
Cm - Micrography by OM using A262 Method ADf - Localized Corrosion

+3 more from this case →

ML00030 — Forging for High Pressure ApplicationM - Microalloyed SteelP - Machined PartAp - Oil and GasCd - Typical manufacturing
Longitudinal section of the fitting in the center of the thickness (2"). Refined ferritic structure.
66
VIEW
ML00030 / Jan.2017
Forging for High Pressure Application
M - Microalloyed SteelP - Machined PartAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Grain refined structure
Longitudinal section of the fitting in the center of the thickness (2"). Refined ferritic structure.
63
VIEW
ML00030 / Jan.2017
Forging for High Pressure Application
M - Microalloyed SteelP - Machined PartAp - Oil and GasCd - Typical manufacturing
Cm - Nital Etched Micrography by OMDf - Grain refined structure