Microstructure

4 cases · 31 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Microstructure: Bainite Standard: API clear all

Microstructure — sub-branches

Austenite 2Bainite 2Banded Structure 1Clad Interface 20Fusion Line 3Grain refined structure 1Martensite 2

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Image by scanning electron microscopy of the metallurgically bonded interface of the internally cladded pipe. It is a longitudinal seam welded pipe, with substrate in low alloy steel X65 and clad plate in Alloy 625 (welded by a solid state process). The region is a detail in the side of the Ni alloy clad plate where a grain refinement has occurred probably due to recrystallization of a strain hardened region during later heat treatment. The microhardness of this region is a lot higher than the value obtained out of this region, in the clad plate.
904
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Oxalic Acid Electrolytic EtchDf - Clad Interface
Image by scanning electron microscopy of the metallurgically bonded interface of the internally cladded pipe. It is a seamless pipe in a low alloy steel X70 cladded by welding overlay of Alloy 625 (by automatic GTAW process). The region is a detail of the interface inside the Ni alloy weld metal, presenting columnar grains and intragranular preciptation. The pipe was heat treated before bending (solution annealing) and after bending (quenching and tempering to meet X70 grade). The microhardness of this region is higher than the value obtained out of this region, in the overlay.
656
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Electrolytic Etch Micrography by SEMDf - Clad Interface
Micrographic detail of the AISI 4130 forging, 5/8" thickness, close to the welded region, in the longitudinal section. Bainitic and tempered martensitic structure.
47
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Martensite
The micrography shows the martensitic region of the tube HAZ responsible for the hydrogen cracking, presenting too high hardness level (600 HV). It is a fresh martensite since the joint was welded in one pass and there was no PWHT.
45
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Martensite

More from these cases

ML00133 — Seam Welded Pipe Cladded with Alloy 625M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Micrographic detail of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure,
50
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the pipe at the interface with the clad plate, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
55
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrography of a longitudinal section of the pipe at the interface with the clad plate, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
51
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrographic detail of a longitudinal section of the pipe at the interface with the clad plate, with Nital etch that reveals only the low alloy steel structure, to the left side of the image. The metallurgical bonding of the claded plate to the substrate is evident since there are no voids or defects.
47
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrography showing the positions of Vickers microhardness measurements in the longitudinal micrography, in the pipe steel substrate (dot 1 - 266 HV100g), very close to the interface inside the clad plate (dot 2 - 429 HV100g) and a little far from the interface inside the Ni clad plate (dot 3 - 358 HV100g).
50
VIEW
ML00133 / May.2018
Seam Welded Pipe Cladded with Alloy 625
M - LAS / Ni AlloyP - Longitudinal Seam Welded PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface

+8 more from this case →

ML00132 — Seamless Pipe Overlaid with Alloy 625M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Micrographic detail of a longitudinal section of the pipe substrate showing a uniform bainitic microstructure.
68
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the pipe at the overlay fusion line, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
67
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrography of a longitudinal section of the pipe at the overlay fusion line, with Nital etch that reveals only the low alloy steel structure, to the left side of the image. Some decarburization of the low alloy steel substrate is evident since the microstructure is slightly different a little far from the interface.
66
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrographic detail of a longitudinal section of the pipe at the interface with the clad plate, with Nital etch that reveals only the low alloy steel structure, to the left side of the image.
59
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface
Micrography showing the positions of Vickers microhardness measurements in the longitudinal micrography, in the pipe steel substrate (dot 1 - 217 HV100g), very close to the interface inside the overlay (dot 2 - 370 HV100g) and a little far from the interface inside the Ni clad plate (dot 3 - 229 HV100g).
56
VIEW
ML00132 / May.2018
Seamless Pipe Overlaid with Alloy 625
M - LAS / Ni AlloyP - Seamless PipeAp - Oil and GasCd - Welding
Cm - Nital Etched Micrography by OMDf - Clad Interface

+5 more from this case →

ML00072 — Liquation Cracks in a High Strength JointM - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Micrographic detail of the X65 pipe, 5/8" thickness, in the longitudinal section. The refined ferritic structure with bainitic bands is responsible for obtaining the 65 Ksi YS for a low carbon manganese ferritic structure.
48
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Banded Structure
ML00052 — Cold Cracks in API 5CT L80 Tube Welded to a Structural PartM - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Micrography of the low alloy steel tube at the fusion line, presenting a martensitic structure at the HAZ and acicular ferrite in the weld metal.
41
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Fusion Line
Micrographic detail of the fusion line of the carbon steel plate, by scanning electron microscopy, showing the bainitic structure at the HAZ and ferritic structure in the weld metal.
34
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Fusion Line
Micrographic detail of the fusion line of the low alloy steel tube, by scanning electron microscopy, showing the martensitic structure at the HAZ and acicular ferritic structure in the weld metal.
29
VIEW
ML00052 / Apr.2017
Cold Cracks in API 5CT L80 Tube Welded to a Structural Part
M - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by SEMDf - Fusion Line