S32760

2 cases · 40 images

Crevice Corrosion in a Subsea System — Aspect Before Analysis

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Aspect of the cracked valve body, after disassembling and removing the internal parts. The valve is part of a lot that was manufactured by forging a cubic 170mm from a forged bar in SDSS UNS S32760, and heat treated (solution annealed) by the forging company. The fabrication using these bodies included the machining, fillet weld two inserts in Alloy 625, machining again, assembling the internals, and pressure test at 15,000 psi. The cracking occurred during test, only for this valve body.
676
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Cracking
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.
945
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

More from these cases

ML00134 — Brittle Fracture of a Superduplex Valve BodyM - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Detailed aspect of the cracking, straight and presenting a brittle aspect.
122
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Cracking
Detail of the internal bore, showing a brittle crack through the wall.
106
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - Cracking
Aspect of a section cut transverse to the center of the body. The crack is brittle, trough wall, and was arrested in the region where the valve body was welded to the insert.
105
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - Transverse Section AspectDf - Cracking
Microstructural analysis of the valve body structure, close to the position where the cracking has occurred. The structure is ferritic austenitic, with a large amount of detrimental phases associated to the ferritic structure, probably sigma phase.
106
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Sigma
Micrographic detail of the valve body structure, close to the position where the cracking has occurred. The structure is ferritic austenitic, with a large amount of detrimental phases associated to the ferritic structure, probably sigma phase.
102
VIEW
ML00134 / Aug.2020
Brittle Fracture of a Superduplex Valve Body
M - Super Duplex Stainless SteelP - Fabrication WeldAp - SubseaCd - Brittle Fracture
Cm - NaOH Electrolytic Etched MicroDf - Sigma

+25 more from this case →

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
Micrography of a transverse section of the forged bar in the center of the thickness. Ferrite and austenite. Coarse structure.
74
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - NaOH Electrolytic Etched MicroDf - Transverse Section
Micrography of a longitudinal section of the forged bar in the center of the thickness. Ferrite and austenite. Coarse structure.
61
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - NaOH Electrolytic Etched MicroDf - Longitudinal Section
Micrography of a transverse section of the forged bar in the center of the thickness. Ferrite and austenite. The ferrite amount, measured by metallographic method, manual counting, is 59%.
53
VIEW
ML00123 / Feb.2018
Non Qualified Superduplex for Subsea
M - Super Duplex Stainless SteelP - BarAp - Oil and GasCd - Not according to spec
Cm - NaOH Electrolytic Etched MicroDf - Transverse Section

+3 more from this case →