At the Surface

31 cases · 77 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

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Micrography of the tooth gear, in a transverse section, close to surface. The material presents light ghost marks that reveal chemical segregations.
80
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Nital Etched Micrography by OMDf - At the Surface
Aspect by SEM of the secondary crack at the blade surface.
18
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Surface Aspect by SEMDf - At the Surface
Metallographic aspect of the wire surface in one strand external wire, showing the presence of oxides.
41
VIEW
ML00175 / Aug.2021
Localized External Wear of a Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Cm - Nital Etched Micrography by OMDf - At the Surface
Aspect of one region where the cracks appeared, after grinding and polishing. Several branched cracks located in welded regions. It is the region where the sample was taken.
36
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Aspect Before AnalysisDf - At the Surface
Micrography of a longitudinal section of the tubing where the fracture occurred. the left side is the outer diameter and the right side is the inner diameter.
37
VIEW
ML00167 / Aug.2020
Fatigue of a Flared Tubing Connection
M - Austenitic Stainless SteelP - TubingAp - EngineCd - Mechanical Fatigue
Cm - Oxalic Acid Electrolytic EtchDf - At the Surface
SAMPLE 3, CLOSE TO THE SURFACE OF SIDE A - Micrography, as polished, of the oxides at the process side. In this region there is an oxide layer, not continuous but with no localized penetrations.
43
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - As polished micrographyDf - At the Surface
Micrography of the wheel at the surface that was quenched and tempered. The material presents a tempered martensitic structure, with hardness that varied from 327HB to 363HB.
55
VIEW
ML00158 / Feb.2020
Surface Hardened Carbon Steel Wheel
M - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - At the Surface
Aspect of the back of the coaster after grinding. The coating was partially removed. The chemical analysis was conducted in the ground part to obtain the composition of the substrate, that showed to be a yellow brass alloy. It is interesting to note that the alloy presented 2.3% lead.
63
VIEW
ML00156 / Jan.2020
Antique Silver Plated Decorative Piece
M - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Cm - Preparation TechniqueDf - At the Surface

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.
51
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
ML00175 — Localized External Wear of a Wire RopeM - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Metallographic aspect of the wire surface in the core wire of the IWRC, presenting the galvanized layer.
35
VIEW
ML00175 / Aug.2021
Localized External Wear of a Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Cm - Nital Etched Micrography by OMDf - At the Surface
ML00160 — High Temperature Degradation of 310SSM - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
SAMPLE 3, CLOSE TO THE SURFACE OF SIDE B - Micrography, as polished, of the oxides at the electric furnace environment side. In this region the oxide layer is thinner than in the process side.
46
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - As polished micrographyDf - At the Surface
SAMPLE 1, CLOSE TO THE SURFACE OF SIDE A - Micrography, as polished, of the oxides at the process side. In this region the oxide layer is penetrating into the austenitic grain boundaries, creating a crack like effect.
56
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - As polished micrographyDf - At the Surface
SAMPLE 1 AT 1 mm THICKNESS, SIDE B - Micrographic detail of the austenite with secondary precipitation, close to the surface exposed to the furnace environment. This NaOH electrolytic etch is adopted to colour sigma phase and at this position there are no special formation of sigma in the grain boundaries and there are no oxide penetrations, confirming that the environment is important to create the damage and the internal side of the tube is responsible for the quick degradation in high temperature.
25
VIEW
ML00160 / Apr.2020
High Temperature Degradation of 310SS
M - Austenitic Stainless SteelP - Rectangular TubeAp - Chemical IndustryCd - Scaling
Cm - NaOH Electrolytic Etched MicroDf - At the Surface
ML00158 — Surface Hardened Carbon Steel WheelM - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Micrography of the wheel at the hardened surface, presenting a refined martensitic structure, tempered for average hardness of 346 HB.
50
VIEW
ML00158 / Feb.2020
Surface Hardened Carbon Steel Wheel
M - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - At the Surface
ML00156 — Antique Silver Plated Decorative PieceM - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Aspect of the coaster surface grooves, by scanning electron microscopy in a low magnification, showing in the right side the flat region that serves as a support; and in the left side the decorative grooves. The smooth surface in the groove suggests that the coasters were manufactured by casting.
66
VIEW
ML00156 / Jan.2020
Antique Silver Plated Decorative Piece
M - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Cm - Surface Aspect by SEMDf - At the Surface
Detail of the previous photo showing the flat surface in the right side and the grooves in the left side. The flat side is scratched and the grooves presented a smooth finishing (with dendritic morphology).
57
VIEW
ML00156 / Jan.2020
Antique Silver Plated Decorative Piece
M - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Cm - Surface Aspect by SEMDf - At the Surface
Detail of the flat scratched region of the coaster surface. The dark grey "nodules" are lead (Pb) base inclusions.
50
VIEW
ML00156 / Jan.2020
Antique Silver Plated Decorative Piece
M - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Cm - Surface Aspect by SEMDf - At the Surface
Detail of the groove region, showing a typical casting morphology at the surface: smooth and presenting a dendritic aspect with interdendritic shrinkage. Some dark grey "nodules" with Pb inclusions are also observed.
51
VIEW
ML00156 / Jan.2020
Antique Silver Plated Decorative Piece
M - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Cm - Surface Aspect by SEMDf - At the Surface