Ferrous Alloys

9 cases · 44 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Application: Ship Capture method: Scanning Electron Microscope clear all

Ferrous Alloys — sub-branches

Carbon Steel 6Cast Iron 2High Alloy Steel 2Low Alloy Steel 3

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Even in a sound tooth there are regions of pitting, and foreign incrustation, probably caused by metal removal and high contact spots.
53
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Surface Aspect by SEMDf - Pitting
Aspect of the spring surface, with a layer of corroded products, and pits.
36
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - Surface Aspect by SEMDf - Corrosion
Fracture surface aspect at the scanning electron microscopy (SEM) of the clamp OD, showing different planes of propagation of the fracture.
42
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Fractography by SEMDf - Fracture
Micrographic detail by scanning electron microscopy of the interface between the two thermal spray layers, the first one in stainless steel (bottom of the figure) and the second one, at the surface,in tungsten carbide (top of the figure). The composition of the first layer is similar to the base metal (lean duplex) and the composition of the second layer is WC in a Co matrix.
16
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - Electrolytic Etch Micrography by SEMDf - Thermal Spray Layer
The fracture surface of the casting cylinder presented, at the internal surface, interconnected graphite flakes and a corroded matrix.
73
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Fractography by SEMDf - Close to the Internal Surface
Micrography of the seam welded joint, autogenous. The localized dissolution occurrs exactly at the weld metal that presents a bainitic structure and Vickers (100g) microhardness values about 230HV, compared to the heat affected zone presenting average of 202 HV and the base metal presenting average of 180HV.
59
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 SEMDf - Welded Joint
Corroded spots (shallow pits full of products) at the spring surface.
80
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Corrosion
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

ML00181 — Wear of a Carburized Hypoid GearM - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Aspect of the fractured tooth in a region presenting pitting, opening voids, and cracks.
52
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Surface Aspect by SEMDf - At the Surface
Aspect of the fractured tooth surface in a region presenting pitting, spalling and cracks.
42
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Surface Aspect by SEMDf - Spalling
Microscopic aspect of the cracks at the tooth surface. The cracks are flat and propagating longitudinally to the tooth (and secondary short transverse).
45
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Surface Aspect by SEMDf - Cracks
Microscopic aspect of the fracture, propagating by contact fatigue.
43
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Fractography by SEMDf - Fatigue Fracture
ML00172 — Brittle Fracture of a LAS Valve SpringM - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Micrographic detail of the martensitic structure, clearly obtained from a refined previous austenitic structure .
19
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - Nital Etched Micrography by SEMDf - Martensite
Micrographic detail of the martensitic structure.
19
VIEW
ML00172 / Mar.2021
Brittle Fracture of a LAS Valve Spring
M - Low Alloy Medium Carbon QTP - SpringAp - Oil and GasCd - Brittle Fracture
Cm - Nital Etched Micrography by SEMDf - Martensite
ML00171 — Corrosion Fatigue of U Bolt Pipe ClampM - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Detail by scanning electron microscop of the clamp surface showing several cracks, parallel. In this image the cracks appear horizontal, but the photo was taken with the axis of the clamp in the vertical direction which means that the cracks are transverse to the axis.
41
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Surface Aspect by SEMDf - Multiple cracks
Detailed aspect of the previous figure showing the parallel cracks, transverse to the axis.
37
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Surface Aspect by SEMDf - Multiple cracks
Detail by scanning electron microscopy of the pits in the metallographic longitudinal section of the clamp, at the surface (left side of the image). There are cracks emanating from the pits.
27
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Nital Etched Micrography by SEMDf - Crack
Detail by scanning electron microscopy of the cracks emanating from the pits in the metallographic longitudinal section of the clamp, at the surface (left side of the image).
25
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Micrography by SEMDf - Crack
Metallographic aspect by scanning electron microscopy of one secondary cracking, paralell to the fracture surface, growthing with an irregular path and transgranular morphologyy.
28
VIEW
ML00171 / Feb.2021
Corrosion Fatigue of U Bolt Pipe Clamp
M - Low Carbon SteelP - BoltAp - ShipCd - Corrosion Fatigue
Cm - Micrography by SEMDf - Corrosion Cracking

+3 more from this case →

ML00147 — WC Layer Detached from a Cast Lean DuplexM - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Micrographic detail of the first thermal spray layer, in stainless steel with the same composition of the base metal (lean duplex).
16
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - Electrolytic Etch Micrography by SEMDf - Thermal Spray Layer
Micrographic detail, by scanning electron microscopy, of the duplex, austenitic and ferritic, structure with sigma phase.
16
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - Electrolytic Etch Micrography by SEMDf - Sigma
ML00141 — Brittle Fracture of a Corroded Gray Cast IronM - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
The fracture surface of the casting cylinder presented, in the center of the thickness, cleavage facets and graphite decohesion that corresponds to a brittle fracture of the material.
61
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Fractography by SEMDf - In the Center of the Thickness
The fracture surface of the casting cylinder presented, close to the external surface, a more ductile aspect of the fracture.
58
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Fractography by SEMDf - Close to the External Surface
Fractographic detail of the interconnected graphite flakes and corroded matrix.
50
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Fractography by SEMDf - Corrosion
Fractographic detail of the graphite decohesion and cleavage facets in the center of the cast cylinder thickness.
47
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Fractography by SEMDf - Brittle Fracture
Micrography of the longitudinal section of the cylinder, at the external diameter (right side of the figure), presenting smaller interdendritic graphite flakes in a ferritic-perlitic matrix. This surface is painted.
32
VIEW
ML00141 / Jul.2018
Brittle Fracture of a Corroded Gray Cast Iron
M - Gray Cast ironP - CastingAp - EngineCd - Brittle Fracture
Cm - Nital Etched Micrography by SEMDf - Graphite in Flakes
ML00140 — Preferential Corrosion of Pipe Seam WeldM - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Micrography at the scanning electron microscopy showing the deposits inside the crevice. The microanalysis by EDS revealed the presence of Fe, O, as well as Cl and S.
35
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Micrography by SEMDf - Corrosion
ML00137 — Brittle Fracture of a 15-5 PH Valve SpringM - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Corroded spots (shallow pits full of products) at the spring surface.
75
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Surface Aspect by SEMDf - Corrosion
The scanning electron microscopy image presents the surface of the spring (top of the figure) where it was broken (the fracture is in the bottom of the figure). It is possible to see that there is a product at the surface and the material presents intergranular fracture, suggesting there was a hydrogen embrittlement effect. Important to observe that the material does not present pits.
58
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - At the Surface
The scanning electron microscopy image presents the fracture surface at the fracture initiation point. The fracture is intergranular.
54
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture
Image detail presenting the intergranular fracture surface at the fracture initiation point.
46
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - Intergranular Fracture
Fracture micromechanism changing from intergranular to transgranular, as the fracture is propagating.
45
VIEW
ML00137 / Mar.2021
Brittle Fracture of a 15-5 PH Valve Spring
M - Precipitation Hardened Stainless SteelP - SpringAp - Oil and GasCd - Brittle Behavior
Cm - Fractography by SEMDf - Fracture

+4 more from this case →

ML00103 — Brittle Fracture of a Free-Cutting ConnectorM - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Details of the inclusion decohesion and cleavage.
89
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Fractography by SEMDf - Cleavage Facets
Details of the cleavage fracture in the ferritic structure.
86
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
Details of the intergranular fracture, probably associated to cementite at grain boundaries.
68
VIEW
ML00103 / Nov.2017
Brittle Fracture of a Free-Cutting Connector
M - Low Carbon SteelP - Machined PartAp - ShipCd - Brittle Fracture
Cm - Fractography by SEMDf - Intergranular Fracture