Optical Microscope

5 cases · 28 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Damage Standard: API Detail focus: Sampling and Analysis clear all

Optical Microscope — sub-branches

As polished micrography 4Kalling Etched Micrography by OM 6Nital Etched Micrography by OM 18

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Micrography of a longitudinal section of the pipe, at the external pipe surface, where there is a corroded spot. The microstructure is tempered martensite and at the surface the pipe is slightly decarburized.
28
VIEW
ML00169 / Nov.2020
Drill Pipe Fracture in the Pipe Body
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - External Surface
Micrography of the pipe transverse section presenting a granular microstructure.
147
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Transverse Section
The liquation crack is a hot crack in the base metal (at the HAZ) that induces a solidification crack in the weld metal.
66
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 - Weld Metal
Low carbon plate base metal presenting the ferritic perlitic structure.
55
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 - Base Metal
13Cr SS longitudinal section micrography, at the collapsed region, showing a ferritic matrix structure (overtempered) with the previous austenite grain boundaries decorated by phases (carbides and probably martensite islands), indicating that the material was exposed to a high tempering temperature that created a partial austenitizing condition. It explains the material low toughness and lower strenght (than required).
437
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Longitudinal Section

More from these cases

ML00169 — Drill Pipe Fracture in the Pipe BodyM - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Micrography of a longitudinal section of the pipe, at the internal pipe surface, where the coating was detached. The strain hardening effect of the blasting is evident. The microstructure is tempered martensite and the surface is slightly decarburized.
28
VIEW
ML00169 / Nov.2020
Drill Pipe Fracture in the Pipe Body
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrography of a longitudinal section of the pipe, at the internal pipe surface, where the coating was detached. The strain hardening effect of the blasting is evident. The microstructure is tempered martensite and the surface is slightly decarburized.
26
VIEW
ML00169 / Nov.2020
Drill Pipe Fracture in the Pipe Body
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Close to the Internal Surface
Micrographic detail of the strain hardening effect, probably generated by blasting before applying the coating. The microstructure is tempered martensite and the surface it is slightly decarburized.
23
VIEW
ML00169 / Nov.2020
Drill Pipe Fracture in the Pipe Body
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - Nital Etched Micrography by OMDf - Internal Surface
Drill Pipe Fracture in the Pipe Body
2
VIEW
ML00169 / Nov.2020
Drill Pipe Fracture in the Pipe Body
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - As polished micrographyDf - External Surface
Drill Pipe Fracture in the Pipe Body
2
VIEW
ML00169 / Nov.2020
Drill Pipe Fracture in the Pipe Body
M - Low Alloy Medium Carbon QTP - Drill PipeAp - O&G Well DrillingCd - Corrosion Fatigue
Cm - As polished micrographyDf - External Surface

+2 more from this case →

ML00140 — Preferential Corrosion of Pipe Seam WeldM - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Micrographic detail of the microstructure close to the corroded area showing the heat affected zone of the autogenous weld, with a refined grain size. The hardness level here is 202HV average, compared to the base metal that is 180HV average.
37
VIEW
ML00140 / May.2019
Preferential Corrosion of Pipe Seam Weld
M - Low Carbon SteelP - Longitudinal Seam Welded PipeAp - ShipCd - Preferential Dissolution
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
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 cracks at the fusion line of the welded joint, at the connector side. The cracking presents morphology of melting regions of impurities at grain boundaries of the large grains of the heat affected zone (HAZ).
57
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 - Fusion Line
Micrography of the AISI 4130 forging, 5/8" thickness, close to the welded region, in the longitudinal section.
42
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 - Base Metal Left Side
Micrographic detail of the AISI 4130 forging, 5/8" thickness, close to the welded region, in the longitudinal section.
45
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 - Base Metal Left Side
Micrography of the X65 pipe, 5/8" thickness, in the longitudinal section.
45
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 - Base Metal Right Side
Micrographic detail of the X65 pipe, 5/8" thickness, in the longitudinal section.In the center of the pipe thickness there is a segregation band of bainitic structure. The cracking was not associated to the pipe but to the other side, the forged connector.
43
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 - Base Metal Right Side

+2 more from this case →

ML00052 — Cold Cracks in API 5CT L80 Tube Welded to a Structural PartM - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
High Strenght Low Alloy steel tube, base metal, presenting the bainitic structure.
54
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 - Base Metal
Micrography of the low carbon steel plate at the fusion line, presenting a bainitic structure at the HAZ and ferritic structure in the weld metal.
82
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
Micrography of the weld metal in the center of the fillet showing a 100% acicular ferrite that is a microestructure of a high strenght steel, evidenced the effect of the dilution of the tube chemistry in the weld metal.
40
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 - Weld Metal
ML00039 — Collapse in Tubular 13CrM - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
13Cr SS in the longitudinal section, at the collapsed region. Non uniform structure (ferritic matrix and decorated prior austenite grain boundaries) that evidences an usuitable heat treatment during fabrication, and explains the material low strenght.
54
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Longitudinal Section
13Cr SS in the transverse section, at the collapsed region, showing a non uniform structure that evidences an usuitable heat treatment during fabrication, and explains the material low strenght.
29
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Transverse Section
13Cr SS transverse section micrography, at the collapsed region, showing a ferritic matrix structure (overtempered) with the previous austenite grain boundaries decorated by phases (carbides and probably martensite islands), indicating that the material was exposed to a high tempering temperature that created a partial austenitizing condition. It explains the material low toughness and lower strenght (than required).
29
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Transverse Section
The micrography of the 13Cr SS in the transverse section, far from the collapsed region, shows a uniform tempered martensitic structure.
27
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Transverse Section
The micrography of the 13Cr SS in the transverse section, far from the collapsed region, shows a uniform tempered martensitic structure.
26
VIEW
ML00039 / Apr.2017
Collapse in Tubular 13Cr
M - Martensitic Stainless SteelP - Seamless PipeAp - Oil and GasCd - Heat Treatment Defect
Cm - Kalling Etched Micrography by OMDf - Transverse Section