Surface layer of Thermal Spray

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Crevice Corrosion in a Subsea System — Aspect Before Analysis

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Macroscopic aspect of the outer diameter of the flanged sleeve presenting adhered products at the surface. The flanged sleeve was manufactured by centrifugal casting in a lean duplex stainless steel and it was externally coated by thermal spray (TS) in a position of sealing. After 5 years in service the system suffered leakage.
569
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - Aspect Before AnalysisDf - External Surface
Longitudinal cracks in the surface of the pin, detected by dye check, after high pressure hydrostatic test.
658
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - Aspect by NDTDf - General View
Micrography, as polished, of the transverse section of the forged pin with the layer applied by a (thermal) spray and fuse process. The structure of the layer that is 0.7 mm thick, presented entrapped pores and globular oxides. The layer was melted after application by thermal spray (in this case using a flame) and the pin was quenched and tempered after the full application and melting of the layer.
360
VIEW
ML00109 / Jan.2018
Thermal Spray and Fuse Layer in Forged Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Thermal spray
Cm - As polished micrographyDf - Transverse Section
Shaft pinion presenting the bearing surface, with machining markes, from where the thermal spray layer was detached. The diameter of the 880 mm long shaft in this region is about 75 mm.
426
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Aspect Before AnalysisDf - General View

More from these cases

ML00147 — WC Layer Detached from a Cast Lean DuplexM - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Detail of the external surface of the sleeve where the surface coating was detached, creating a lack of sealing condition.
67
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - Surface AspectDf - External Surface
General view of the 10" diameter flanged sleeve, 1/2" wall thickness, manufactured by centrifugal casting of lean duplex stainless steel (DSS), Alloy 2304 (without Mo), with an external coating applied by thermal spray (TS). The sleeve is assembled in a shaft. The internal environment is oil and a seal box is assembled in the external side that is wet with seawater.
56
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - Aspect Before AnalysisDf - General View
Longitudinal slice of the flanged sleeve, 180 mm long, in a macrography presenting the 1/2" tubular wall thickness where the sealing was applied. The external surface of the sleeve (seawater wet) is in the left side of the figure and the internal surface (oiled) is in the right side. The flange is to the top of the figure.
52
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - Longitudinal Section AspectDf - General View
Macrographic aspect of the sleeve longitudinal section where the coating was applied in the external side (top of the figure). It is possible to see that the sleeve was manufactured by centrifugal casting, with elongated grains from the external side, and equiaxial grains close to the internal side (bottom of the figure). There is a weaved interface between the sleeve and the first layer of thermal spray coating, 1 mm thick; and a second layer of thermal spray coating, 0.2mm thick (almost imperceptible at this low magnification).
49
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - NaOH Electrolytic Etched MacroDf - Coating Layer
Micrography of a longitudinal section of the sleeve, at the external surface where there are two layers of coating. The electrolytic etch evidenced the duplex stainless steel substrate (bottom of the figure) and the weave interface of the substrate and the first thermal spray layer, about 1 mm thick, in a stainless steel. The surface layer, of tugnsten carbide, about 0.2 mm thick, is black and not clearly visible in this figure.
50
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - NaOH Electrolytic Etched MicroDf - External Surface

+24 more from this case →

ML00110 — Non Conformance in Spray and Fuse PinM - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Micrography, as polished, of the transverse section of the forged pin with the layer applied by a (thermal) spray and fuse process. The layer presented entrapped pores and globular oxides. It was melted after application by thermal spray (in this case using a flame) but the pin was not heat treated after the full application and melting of the layer and the base metal is ferritc-pearlitic.
51
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - As polished micrographyDf - Transverse Section
Micrography, as polished, of the transverse section of the forged pin with the layer applied by a (thermal) spray and fuse process. The layer was melted after thermal spray application and the layer presents a continuous matrix, but there are globular oxides and pores entrapped.
36
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - As polished micrographyDf - Surface Layer
Micrographic detail, as polished, of the transverse section of the forged pin at the interface between the pin and the spray and fuse layer. The interface presents globular oxides and small pores, entrapped.
35
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - As polished micrographyDf - Surface Layer
Low magnification micrography of the interface between the pin and the spray and fuse layer. Close to the surface, under the layer, the pin presents a ferritic perlitic structure, non conform with the high strenght requirement. Transverse section.
37
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - As polished micrographyDf - Low Mag
Micrography of the pin close to the interface with the spray and fuse layer. Transverse section. The fuse was conducted in high temperature and the pin was cooled very slowly, forming a ferritic-perlitic structure even for this high hardenability base metal.
35
VIEW
ML00110 / Jan.2018
Non Conformance in Spray and Fuse Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Heat Treatment Defect
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite

+6 more from this case →

ML00109 — Thermal Spray and Fuse Layer in Forged PinM - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Thermal spray
Micrography, as polished, of the transverse section of the forged pin with the layer applied by a (thermal) spray and fuse process. The layer was melted after thermal spray application and the layer presents a continuous matrix, but there are globular oxides and pores entrapped.
29
VIEW
ML00109 / Jan.2018
Thermal Spray and Fuse Layer in Forged Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Thermal spray
Cm - As polished micrographyDf - Surface Layer
Micrographic detail, as polished, of the transverse section of the forged pin at the interface between the pin and the spray and fuse layer. The pin was heat treated after the thermal spray, and fuse treatment. The interface presents a higher concentration of globular oxides and pores, entrapped.
23
VIEW
ML00109 / Jan.2018
Thermal Spray and Fuse Layer in Forged Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Thermal spray
Cm - As polished micrographyDf - Surface Layer
Low magnification micrography of the interface between the pin and the spray and fuse layer. Close to the surface, under the layer, the pin presents a quenched and tempered structure, compatible with a high strenght requirement. Transverse section.
20
VIEW
ML00109 / Jan.2018
Thermal Spray and Fuse Layer in Forged Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Thermal spray
Cm - Nital Etched Micrography by OMDf - Surface Layer
Micrography of the pin close to the interface with the spray and fuse layer. Transverse section. The fuse is conducted in high temperature and the pin was quenched and tempered after the thermal spray deposition and fuse by flame (in this case the melting of the applied layer was conducted by a oxifuel flame.
21
VIEW
ML00109 / Jan.2018
Thermal Spray and Fuse Layer in Forged Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Thermal spray
Cm - Nital Etched Micrography by OMDf - Martensite
Micrographic detail of the tempered martensite structure close to the interface with the spray and fuse layer. Transverse section. The fuse is conducted in high temperature and the pin was heat treated after the thermal spray deposition and fuse.
16
VIEW
ML00109 / Jan.2018
Thermal Spray and Fuse Layer in Forged Pin
M - Low Alloy Medium Carbon QTP - Tubular ForgingAp - O&G Well DrillingCd - Thermal spray
Cm - Nital Etched Micrography by OMDf - Martensite

+3 more from this case →

ML00108 — Thermal Spray Layer in a Pinion ShaftM - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Detail of the detached layer, about 1.5 mm thick.
48
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Aspect Before AnalysisDf - Layer Detachment
Macrographic detail of the thermal spray layer in a position of the shaft where it was not detached. Longitudinal section of the shaft. The waves are the machining marks created to anchor the thermal spray layer, that is about 1.5mm thick.
41
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - NItal Etched MacroDf - Longitudinal Section
Micrography of the thermal spray (TS) layer showing the different alloys, gray oxides and black voids. The Ni base TS alloy is of a yellow colour at the interface with the shaft substrate (in the left). The Cr base TS alloy appears white, similar to the shaft substrate. Longitudinal section of the shaft.
42
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - As polished micrographyDf - Coating Layer
Micrographic detail, as polished in a longitudinal section, of the interface between the shaft substrate and the thermal spray layer. In the left it is the shaft substrate also presenting parts of aligned inclusions (gray). In the center it is the Ni base TS alloy and in the right it is the Cr base TS alloy. There are also black voids and grey oxides.
33
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - As polished micrographyDf - Coating Layer
Micrography of the interface between the shaft surface and the thermal spray layer. The shaft steel presents a quenched and tempered structure. Longitudinal section.
32
VIEW
ML00108 / Dec.2017
Thermal Spray Layer in a Pinion Shaft
M - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
Cm - Nital Etched Micrography by OMDf - Coating Layer

+7 more from this case →