Atlas

4 cases · 14 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Condition: Fabrication Defect Capture method: Scanning Electron Microscope Detail focus: Sampling and Analysis clear all

Results

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Quenched and tempered heat affected zone of the forging.
75
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 SEMDf - Heat Affected Zone
Fractography of the roller bearing, close to the external surface. In this position the fracture of the cylindrical roller bearing shows micromechanisms of decohesion at large carbides (cracked) and quasecleavage, typical of overloading this high strength tool steel (martensitic with carbides at 64 HRc).
75
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Fractography by SEMDf - Close to the External Surface
Fractographic detail of the longitudinal Charpy V testpiece, broken at -46°C and presenting energy of 64J (the average energy of three tespieces was 70J). The Charpy V testpiece was removed from the center of the bar. The micromechanism is quasicleavage and the test in this direction presented energy values superior than the minimum requirement of 45J.
944
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - Fractography by SEMDf - Broken Testpiece
Micrographic detail of the bainitic structure at the HAZ of the carbon steel plate, by scanning electron microscopy.
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 SEMDf - Heat Affected Zone

More from these cases

ML00131 — Brittle Failure of a Soft Roller BearingM - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Aspect of the roller bearing fracture surface, by scanning electron microscopy, close to the internal surface. In this position the fracture shows ductile micromechanisms (dimples) as well as decohesion of large carbides and (brittle) cleavage facets, typical of overloading this low strenght, and low toughness, ferritic structure (21 HRc). The structure in this region, ferritic with large broken carbides and small rounded carbides, is of a low toughness, as indicated by the fracture.
54
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Fractography by SEMDf - Close to the Internal Surface
Fracture micromechanism at a region close to the internal surface. In this position the fracture shows ductile micromechanisms (dimples) as well as decohesion of large carbides and (brittle) cleavage facets, typical of overloading this low strenght ferritic structure (21 HRc). The structure in this region, ferritic with large broken carbides and small rounded carbides, is of a low toughness, as indicated by the fracture.
44
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Fractography by SEMDf - Close to the Internal Surface
Fracture micromechanism at a region close to the external surface. In this position the fracture shows quasecleavage, as well as decohesion of large carbides. typical of overloading this high strenght martensitic structure (64 HRc).
44
VIEW
ML00131 / Apr.2018
Brittle Failure of a Soft Roller Bearing
M - Wear Resistant SteelP - Roller BearingAp - Mechanical IndustryCd - Heat Treatment Defect
Cm - Fractography by SEMDf - Close to the External Surface
ML00123 — Non Qualified Superduplex for SubseaM - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Fractography of the broken Charpy V testpiece, longitudinal, broken at -46°C and presenting energy of 64J (the average of three values was 70J). In this direction the material presented an energy value higher than the minimum requirement of 45J.
109
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - Fractography by SEMDf - Broken Testpiece
Fractography of the Charpy V testpiece, transverse section, broken at -46°C and presenting energy of 20J (the average of three results was 33J). The coarse structure and the alignement created a condition for low energy results in this specific direction, and the material did not present the minimum requirement of 45J.
103
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - Fractography by SEMDf - Broken Testpiece
ML00052 — Cold Cracks in API 5CT L80 Tube Welded to a Structural PartM - Low Alloy SteelP - Seamless tubeAp - OffshoreCd - Welding Defect
Micrographic detail of the ferritic structure in the weld metal close to the low alloy steel tube, by scanning electron microscopy. The weld metal presents a typical aspect for high strenght weld metal (100% acicular ferrite).
32
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 - Weld Metal
Micrographic detail of the ferritic structure in the weld metal close to the carbon steel plate, by scanning electron microscopy. The weld metal presents a typical aspect for low strenght weld metal (grain boundary and primary ferrite, plus acicular ferrite).
30
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 - Weld Metal
Micrographic detail of the martensitic structure at the HAZ of the low alloy steel tube, by scanning electron microscopy.
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 - Surface Aspect by SEMDf - Heat Affected Zone
Micrographic detail of the weld metal presenting 100% of acicular ferrite. Although the adopted filler metal was of a low strenght type, the dilution of the tube chemistry in the weld created a typically high strenght weld metal.
26
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 - Weld Metal
Micrographic detail in higher magnification of the weld metal presenting 100% of acicular ferrite. It is interesting to observe that the previous austenite grain boundary can be seen but there is no primary ferrite in the grain boundary.
36
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 - Weld Metal