Brass

3 cases · 41 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Results

SortNewestOldestTitle A-ZTitle Z-A
The coasters present a handmake look. The grooves are of different sizes and the octogonal shape is irregular. The pieces presented a weight that suggested that the bright finish is a metallic coating, later identified by EDS analysis as silver coating, typical of a decorative plating.
452
VIEW
ML00156 / Jan.2020
Antique Silver Plated Decorative Piece
M - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Cm - Aspect Before AnalysisDf - General View
Aspect of the CuZn platesheet where it is corroded (cooling medium side). The (hot) air cooler uses treated seawater as the cooling medium and the corroded regions are associated to the regions in the heat exchanger of higher temperatures, and the leakage occurred in regions of contact of the platesheet to cooper alloy tubes.
1167
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Aspect Before AnalysisDf - Corrosion
The fracture micromechanism is ductile for the pin that has been sheared in a condition of controlling the load carrying. Elongated Dimples.
453
VIEW
ML00007 / Dec.2020
Free Machining Brass in Shear Pin
M - BrassP - Machined PartAp - LiftingCd - Shear
Cm - Fractography by SEMDf - Elongated Dimples

More from these cases

ML00156 — Antique Silver Plated Decorative PieceM - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Piece that was analysed by non destructive tests. Octogonal shape. Two irregular grooves. The coaster was manufactured in a cooper alloy substrate and a metallic coating. The analysis to reveal the substrate microstructure was conducted on the back of the part, in a non destructive preparation, that included light grinding, polishing and etching.
61
VIEW
ML00156 / Jan.2020
Antique Silver Plated Decorative Piece
M - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Cm - Aspect Before AnalysisDf - General View
Light grinding the back of the coaster. The surface was only partially ground, removing the metallic coating, and exposing the substrate, that appeared yellow indicating the manufacturing in a cooper alloy.
63
VIEW
ML00156 / Jan.2020
Antique Silver Plated Decorative Piece
M - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Cm - Preparation TechniqueDf - General View
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
Back of the coaster showing the region that was prepared for the non destructive analysis. It was ground and polished (the coating was removed), showing the yellow aspect of the substrate, in the left bottom part of the image.
64
VIEW
ML00156 / Jan.2020
Antique Silver Plated Decorative Piece
M - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Cm - As polishedDf - General View
Image presenting the back of the coaster where the microstructure of the substrate was identified. The composition of the brass (about 35% Zn) indicates that the expected structure is alpha plus beta. The front of the coaster presents two grooves which surface morphology was analyzed by scanning electron microscopy.
65
VIEW
ML00156 / Jan.2020
Antique Silver Plated Decorative Piece
M - BrassP - Decorative PieceAp - OrnamentalCd - Non Destructive Examination
Cm - Surface AspectDf - General View

+10 more from this case →

ML00125 — Dezincification of a Cooler TubesheetM - BrassP - PlateAp - ShipCd - Preferential Dissolution
Micrography of a transverse section of the platesheet presenting a duplex structure, alpha (light yellow) and beta (orange) phases.
214
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - FeCl3+HCl+Ethanol Etched MicroDf - Alpha and Beta
Aspect of the tubesheet after removal of the cooper alloy tubes and water cleaning. The corrosion is more intense in the regions of tube connection.
176
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Surface AspectDf - Corrosion
Transverse section of the tubesheet, after removal of the tubes. The seawater sie is to the top of the figure. It is possible to see regions of localized corrosion close to the tube position and a red layer all through the plate surface.
182
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Transverse Section AspectDf - Corrosion
Macrographic detail of the transverse section of the tubesheet at the cooper alloy tube position, after removal of the 5/8" tube. The red layer at the top of the plate (exposed to the cooling medium - treated seawater) is a region of selective corrosion, dezincification.
169
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Transverse Section AspectDf - Corrosion
Macrographic detail of the transverse section of the tubesheet at the cooper alloy tube position, after removal of the 5/8" tube. The "layer" at the top of the plate (exposed to the cooling medium - treated seawater) is a region of selective corrosion, dezincification. It is possible to see that in the right side of the figure, where the cooper tube was positioned, the corrosion damage is deeper.
153
VIEW
ML00125 / Mar.2018
Dezincification of a Cooler Tubesheet
M - BrassP - PlateAp - ShipCd - Preferential Dissolution
Cm - Transverse Section AspectDf - Dezincification

+13 more from this case →

ML00007 — Free Machining Brass in Shear PinM - BrassP - Machined PartAp - LiftingCd - Shear
Uniform structure of the 1" shear pin all through the section. The edge is the fracture surface.
108
VIEW
ML00007 / Dec.2020
Free Machining Brass in Shear Pin
M - BrassP - Machined PartAp - LiftingCd - Shear
Cm - FeCl3+HCl+H2O solution Etched MacroDf - Longitudinal Section
The fracture surface is flat and smashed due to the shearing action.
87
VIEW
ML00007 / Dec.2020
Free Machining Brass in Shear Pin
M - BrassP - Machined PartAp - LiftingCd - Shear
Cm - Aspect Before AnalysisDf - Fracture
The fracture surface is ductile and the micromechanism is dimples, elongated due to the shearing action.
83
VIEW
ML00007 / Dec.2020
Free Machining Brass in Shear Pin
M - BrassP - Machined PartAp - LiftingCd - Shear
Cm - Fractography by SEMDf - Ductile Fracture
The micrography of the pin far from the fracture surface shows a biphasic brass, and Pb inclusions that are intentional to give a free machining condition for the alloy.
76
VIEW
ML00007 / Dec.2020
Free Machining Brass in Shear Pin
M - BrassP - Machined PartAp - LiftingCd - Shear
Cm - FeCl3+HCl+H2O Etched MicroDf - Two phases
The micrography of the pin at the fracture surface shows a strong plastic deformation as expected during shearing.
69
VIEW
ML00007 / Dec.2020
Free Machining Brass in Shear Pin
M - BrassP - Machined PartAp - LiftingCd - Shear
Cm - FeCl3+HCl+H2O Etched MicroDf - Plastic Deformation