Fabrication Defect

5 cases · 15 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

Capture method: Fractography by SEM clear all

Fabrication Defect — sub-branches

Casting Defect 1Coating Defect 1Heat Treatment Defect 4Not according to spec 4Welding Defect 9

Results

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Aspect by scanning electron microscopy of the brittle fracture surface. in a low magnification view. The fracture presents smashed regions (conditions imposed after the fracture was opened) in the region where the chevron marks indicate it is the failure starting point.
26
VIEW
ML00148 / Sep.2018
Brittle Fracture of a 420 SS Barrel Nut
M - Martensitic Stainless SteelP - Barrel NutAp - LiftingCd - Heat Treatment Defect
Cm - Fractography by SEMDf - Brittle Fracture
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
After opening a crack it was possible to see the fracture appearance.
70
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Fractography by SEMDf - Fracture
The fracture presents an intergranular aspect, and evidences of incipient melting, indicating a liquation cracking has occurred at the plate coarse grain heat affected zone/fusion line.
57
VIEW
ML00069 / May.2017
Liquation Cracks in SAW of Low Carbon Steel
M - Low Carbon SteelP - Fabrication WeldAp - AutomotiveCd - Welding Defect
Cm - Fractography by SEMDf - Intergranular Cracking

More from these cases

ML00148 — Brittle Fracture of a 420 SS Barrel NutM - Martensitic Stainless SteelP - Barrel NutAp - LiftingCd - Heat Treatment Defect
Observing in higher magnification it is possible to see that the fracture presents a mixture of ductile and brittle micromechanisms. The intergranular mechanism indicates that the material is embrittled and the dimples indicate localized overloading conditions.
32
VIEW
ML00148 / Sep.2018
Brittle Fracture of a 420 SS Barrel Nut
M - Martensitic Stainless SteelP - Barrel NutAp - LiftingCd - Heat Treatment Defect
Cm - Fractography by SEMDf - Fracture
Detail of the ductile dimples and the brittle intergranular micromechanisms. This evidence (a mixture of mechanisms) suggests that the embrittlement is localized in some regions of the material.
34
VIEW
ML00148 / Sep.2018
Brittle Fracture of a 420 SS Barrel Nut
M - Martensitic Stainless SteelP - Barrel NutAp - LiftingCd - Heat Treatment Defect
Cm - Fractography by SEMDf - Fracture
Scanning electron microscope fractographic detail of the brittle intergranular micromechanism.
40
VIEW
ML00148 / Sep.2018
Brittle Fracture of a 420 SS Barrel Nut
M - Martensitic Stainless SteelP - Barrel NutAp - LiftingCd - Heat Treatment Defect
Cm - Fractography by SEMDf - Intergranular Fracture
Scanning electron microscope fractographic detail of the ductile dimples.
26
VIEW
ML00148 / Sep.2018
Brittle Fracture of a 420 SS Barrel Nut
M - Martensitic Stainless SteelP - Barrel NutAp - LiftingCd - Heat Treatment Defect
Cm - Fractography by SEMDf - Dimples
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
ML00071 — Reheating Cracking of a CrMo Vessel WeldM - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Intergranular morphology of the fracture in a scanning electron microscopy image.
65
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Fractography by SEMDf - Intergranular Cracking