As polished micrography

3 cases · 16 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Damage Microstructure: Surface layer of Thermal Spray clear all

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Micrography of a longitudinal section of the sleeve, in a region where the two layers applied by thermal spray are sound, not detached. The grey layer (200 micros) is the tugnsten carbide; and the white layer (1000 microns) is a stainless steel. The substrate is white in the bottom of the figure.
24
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - As polished micrographyDf - Thermal Spray Layer
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 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

More from these cases

ML00147 — WC Layer Detached from a Cast Lean DuplexM - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Micrography of a longitudinal section of the sleeve, in a region where the surface layer starts detachment. This grey layer is the tugnsten carbide; and the white layer (1000 microns) is a stainless steel. In this case the first TS layer is sound. The substrate is white in the bottom of the figure.
20
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - As polished micrographyDf - Layer Detachment
Micrography of a longitudinal section of the sleeve, in a region where the surface layer was completely removed. In this position only the stainless steel layer is at the surface. That is why the sealing condition was lost. The substrate is white in the bottom of the figure.
19
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - As polished micrographyDf - Layer Detachment
Micrographic detail of a longitudinal section of the sleeve, in a region where the WC (tungsten carbibe) surface layer was degradated and partially removed.
17
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - As polished micrographyDf - Layer Detachment
Micrographic detail of the WC (tungsten carbibe) surface layer, degradated and partially removed.
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 - As polished micrographyDf - Layer Detachment
Micrography of a longitudinal section of the sleeve, in a region where the surface layer was completely removed. In this position only the stainless steel layer, that is porous and full of oxides, is at the surface. That is why the sealing condition was lost.
17
VIEW
ML00147 / Aug.2018
WC Layer Detached from a Cast Lean Duplex
M - Lean Duplex Stainless SteelP - Centrifugal CastingAp - ShipCd - Lack of Sealing
Cm - As polished micrographyDf - Thermal Spray Layer

+1 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 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, as polished, of the transverse section of the forged pin, showing a crack in the thermal spray layer, thickness about 0.8mm. The spray and fuse process was conducted in a low alloy steel, type AISI 4130, but the quenching and tempering heat treatment was not applied later, and the pin body presented low strenght, evidencing plastic deformation after hydrostatic testing, that cause the layer cracking.
22
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 - Cracks Transverse to the Surface
Micrographic detail of the crack in the thermal spray layer. The spray and fuse layer presented a typically melted structure with entrapped pores and globular oxides.
29
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 - Crack

+1 more from this case →

ML00108 — Thermal Spray Layer in a Pinion ShaftM - High Strength Low AlloyP - ShaftAp - EngineCd - Coating Defect
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