Inconel 718 S-R Failure (Notched/Smooth Combo)
Inconel 718 S-R Failure (Notched/Smooth Combo)
(OP)
Good Morning All,
Kinda urgent issue. I had an N/S S-R test fail at 40+ hours in the notch for Inco 718 (AMS 5662/5663). Naturally we sent more material for the 3 redundant tests all of which broke in the notch in under 2 hours. I checked the solution H/T chart on our end and everything ran OK to the cycle and the lab was to perform the precipitation hardening then run the tests. On their end they say that the H/T ran smooth.
Kinda urgent issue. I had an N/S S-R test fail at 40+ hours in the notch for Inco 718 (AMS 5662/5663). Naturally we sent more material for the 3 redundant tests all of which broke in the notch in under 2 hours. I checked the solution H/T chart on our end and everything ran OK to the cycle and the lab was to perform the precipitation hardening then run the tests. On their end they say that the H/T ran smooth.
- The specimens were taken from a thin walled forging in the longitudinal direction(0.5",~12.7mm)
- I think that maybe the way specimen was machined in respect to the wall/surface defects may have been a factor.





RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
Also, you don't mention test temperature, stress and expected rupture life so I have no idea how your data compares with expected results.
RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
Did you run smooth S-R? What load were you using?
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Plymouth Tube
RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
What were the aged tensile properties?
I also suspect the notches based on personal pain.
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Plymouth Tube
RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
Yes, 2 hours really sounds fishy. Notch quality is one thing, but could they have gotten either the temp or stress wrong? 110ksi at 1300F sure gives a lot faster failures.
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Plymouth Tube
RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
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Plymouth Tube
RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
RE: Inconel 718 S-R Failure (Notched/Smooth Combo)
We have seen similar issues in the past.
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Plymouth Tube