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ML00123 - Feb.2018

Non Qualified Superduplex for Subsea

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.

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Fractography of the V testpiece, , broken at -46°C and presenting energy of 20J (the average of three results was 33J). The 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.
M

Material

Super Duplex Stainless Steel
  • UNS S32760
  • ASTM A 182 grade F55
Ds

Description

The forged was acquired according to to manufacture for a system, but when the material was tested to meet subsea requirements, the average transverse impact energy at -46°C was lower than the minimum requirement (45J) as well as the average was larger than the maximum specified (30 microns). The V in longitudinal and transverse directions evidence the effect as well as the importance of a small austenite spacing.

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Chemistry (% in weight)

0.25%N2 / PREN 41

0.018C; 0.31Si; 0.67Mn; 0.020P; 0.001S; 25.6Cr; 7.25Ni; 3.46Mo; 0.60Cu; 0.60W.

Associated Images
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
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
Micrography of a longitudinal section of the forged bar in the center of the thickness. Ferrite and austenite. The average austenite spacing is 80 microns, a lot larger than the maximum allowed in the specification, of 30 microns. No detrimental phases were identified at the ferrite/austenite interfaces, but the ferrite phase presented a rough aspect. Higher magnification analysis would be required to identify precipitation.
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 - Longitudinal Section
Micrographic detail of the ferrite and austenite structure in the transverse section of the forged bar, in the center of the thickness.
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 - Ferrite and Austenite
Micrographic detail of the ferrite and austenite structure in the longitudinal section of the forged bar, in the center of the thickness.
55
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 - Ferrite and Austenite