Sampling and Analysis

17 cases · 114 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Microstructure: Tempered Martensite Capture method: Optical Microscope clear all

Sampling and Analysis — sub-branches

At the Surface 14Base Metal 16Close to the Internal Surface 2External Surface 3Fusion Line 7Heat Affected Zone 19In the Center of the Thickness 2Internal Surface 4Longitudinal Section 10Microhardness Indentations 1Transverse Section 6Weld Metal 27Weld Repair 3

Results

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Low magnification micrography presenting segregation bands in a martensitic structure. In the segregated regions the Nital etch effect is lower and the bands appear lighter. The black spots and lines are inclusions (some elongated) in the band.
91
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
Quenched and tempered structure of the F22 steel forging, presenting about 230HV10 average hardness.
133
VIEW
ML00178 / Jan.2022
Cold cracks in Cr-Mo Welded Forging
M - CrMo SteelP - ForgingAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Base Metal
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
Low magnification micrography at the weld repair close to the internal surface of the valve body, in a longitudinal section. Weld metal to the bottom and heat affected zone to the top.
42
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Weld Repair
Micrography of the wheel in the center of the thickness. The material presents a coarse structure.
88
VIEW
ML00158 / Feb.2020
Surface Hardened Carbon Steel Wheel
M - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrography of the plate section, as polished, close to the surface that suffered the impact. No evidences of damage.
26
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - As polished micrographyDf - At the Surface
Micrographic aspect of the rolled thread that was heat treated later. Longitudinal section.
134
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Nital Etched Micrography by OMDf - At the Surface
Micrography of the weld metal, at the face, presenting regions of large ferritic grains. The acicular ferrite structure in the columnar (previous austenitic) grains has suffered degradation due to the long heat treatment cycle (12 hours) in high temperature.
97
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Weld Metal

More from these cases

ML00182 — Brittle Fracture of a LAS Fixing RodM - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Low magnification micrography, revealing (in black) the impurities in the segregated bands.
63
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Micro by OM, picric acid+FeCl3+H2O etchDf - Longitudinal Section
ML00178 — Cold cracks in Cr-Mo Welded ForgingM - CrMo SteelP - ForgingAp - O&G Well DrillingCd - Welding Defect
Fusion line of the forging side, in the cap, showing the weld metal (to the top of the image) and the base metal (to the bottom of the image). The heat affected zone hardness is about 270HV10.
108
VIEW
ML00178 / Jan.2022
Cold cracks in Cr-Mo Welded Forging
M - CrMo SteelP - ForgingAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
The columnar grains of the weld metal in the cap presented a martensitic structure.
60
VIEW
ML00178 / Jan.2022
Cold cracks in Cr-Mo Welded Forging
M - CrMo SteelP - ForgingAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal
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 →

ML00162 — Valve Body Crack Growth from Weld DefectsM - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Low magnification micrography at the weld repair close to the internal surface of the valve body, in a longitudinal section. Weld metal to the right and heat affected zone to the left.
30
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Weld Repair
Micrography of the weld repair at the fusion line. At this magnification it is possible to identify several voids at interdendritic positions.
26
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Weld Repair
Micrographic detail of the weld metal presenting hot cracks, at interdendritic positions, interconected.
28
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal
Microstructure of the weld metal close to the fusion line, showing that the dilution effects created zones of higher carbon content, creating a martensitic plus retained austenite microstructure.
29
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrography in low magnification of the cracks in the repair weld metal, showing the dendritic aspect of the hot cracks, formed during welding due to the high content of impurities in a high strength weld metal.
26
VIEW
ML00162 / Apr.2020
Valve Body Crack Growth from Weld Defects
M - Low Alloy Medium Carbon QTP - Valve BodyAp - O&G Well DrillingCd - Fatigue Induced by a Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal
ML00158 — Surface Hardened Carbon Steel WheelM - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Micrography of the wheel at the surface that was quenched and tempered. The material presents a tempered martensitic structure, with hardness that varied from 327HB to 363HB.
55
VIEW
ML00158 / Feb.2020
Surface Hardened Carbon Steel Wheel
M - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - At the Surface
Micrography of the wheel at the hardened surface, presenting a refined martensitic structure, tempered for average hardness of 346 HB.
50
VIEW
ML00158 / Feb.2020
Surface Hardened Carbon Steel Wheel
M - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - At the Surface
Micrographic aspect of the rim microstructure at the surface (internal to the wheel), not the heat treated one. The pearlitic structure is not so coarse than in the center of the thickness.
38
VIEW
ML00158 / Feb.2020
Surface Hardened Carbon Steel Wheel
M - High Carbon SteelP - WheelAp - TransportationCd - Removed From Service
Cm - Nital Etched Micrography by OMDf - Internal Surface
ML00142 — Impact of a .308 Winchester on AR500 PlateM - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Micrography of the plate section, as polished, close to the surface that suffered the impact. At this magnification it is possible to see a deposit over the plate surface, but no evidences of damage in the plate.
25
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - As polished micrographyDf - At the Surface
Micrographic detail of the plate section, as polished, close to the surface that suffered the impact. The deposits at the surface are the melted bullet films.
23
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - As polished micrographyDf - At the Surface
Micrographic detail of the plate section, as polished, close to the surface that suffered the impact. The orange is the copper alloy melted film.
21
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - As polished micrographyDf - At the Surface
Micrographic detail of the plate section, as polished, close to the surface that suffered the impact. The lead alloy melted and formed this gray deposit.
20
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - As polished micrographyDf - At the Surface
Micrography of the plate section, close to the surface that suffered the impact. Smooth waves but no evidences of damage.
15
VIEW
ML00142 / Aug.2018
Impact of a .308 Winchester on AR500 Plate
M - Low Alloy Wear ResistantP - Rolled PlateAp - StructureCd - Non-Pierced
Cm - Nital Etched Micrography by OMDf - At the Surface

+3 more from this case →

ML00130 — Fatigue Fracture of Overloaded BoltsM - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Micrographic aspect of the rolled thread that was heat treated later. Longitudinal section. The bolt was quenched and tempered to 30HRc and presented a martensitic structure.
124
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Nital Etched Micrography by OMDf - At the Surface
The microstructure of the bolt is martensitic in the center of the thickness. Longitudinal section.
110
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Nital Etched Micrography by OMDf - In the Center of the Thickness
Micrographic aspect of the rolled thread that was heat treated later. Longitudinal section.
115
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Nital Etched Micrography by OMDf - At the Surface
The fracture of the bolt occurred associated to the bottom of the thread. Compare this photo with the previous one to understand where the fracture started.
115
VIEW
ML00130 / Jun.2018
Fatigue Fracture of Overloaded Bolts
M - Low Alloy Medium Carbon QTP - FastenerAp - O&G Well DrillingCd - Mechanical Fatigue
Cm - Nital Etched Micrography by OMDf - Longitudinal Section
ML00129 — Non qualified WPS for High Strength SteelM - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Micrography of the weld metal, at the face, presenting regions of large ferritic grains. The acicular ferrite has suffered degradation due to the long heat treatment cycle (12 hours) in a temperature of 640°C, that is higher than the recommended for the D2 filler metal.
78
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Weld Metal
Micrography of the base metal, in low magnification, showing regions of segregations in a quenched and tempered martensitic structure.
52
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of the base metal showing a quenched and tempered martensitic structure. The base metal adopted in the test coupon presented a hardness level of 217HB (Brinell hardness of the certificate) and after the PWHT cycle the measured base metal hardness is 224 HV10.
59
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Base Metal
Micrography of the heat affected zone at the face of the joint. It is possible to see that even close to the fusion line the material was reheated in high temperature, suggesting that the temper bead was effective.
53
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone
Micrography of the heat affected zone at the face of the joint, close to the fusion line. The hardness level at the HAZ was 248 HV10.
58
VIEW
ML00129 / Apr.2018
Non qualified WPS for High Strength Steel
M - Low Alloy Medium Carbon QTP - Welded Testpiece for QualificationAp - Oil and GasCd - Non qualified
Cm - Nital Etched Micrography by OMDf - Heat Affected Zone

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