SS 440C
SS 440C
(OP)
Does anyone have the shear yield strenght of stainless steel 440 C? If anyone does it would be very helpful.
Many thanks,
Tom
Many thanks,
Tom
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RE: SS 440C
I shear load is involved use AISI 420 at 44-50 RC. It still have enough toughness and wear resistance.
http://www.webspawner.com/users/israelkk/
RE: SS 440C
Tom
RE: SS 440C
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: SS 440C
RE: SS 440C
RE: SS 440C
(Torque)/(Second moment of area) = (Shear Stress)/(radius)
I am solving for my shear stress, and comparing it to the shear yield strength of SS 440C.
Any suggestions would be most welcome.
Thanks
Tom
RE: SS 440C
"The impact strength of 17-4PH, especially large size bar in the H900 and H925 conditions, may be very
low at subzero temperatures; consequently, the use of 17-4PH for critical applications at low temperatures
should be avoided."
NIL-HDBK-5 doesn't give any guarantied shear values for 17-4PH.
I think you should go with Custom 455 H1000.
Can you give more info on the environment.
Is it possible that the fracture is actually a fatigue (dynamic) fracture?
How many turns to fracture?
http://www.webspawner.com/users/israelkk/
RE: SS 440C
We had the shaft analyzed at a lab, and they said it was a ductile fracture due to overloading. My problem right now, it that our shaft is undergoing bending and twisting, and I am having a little trouble bring the two together to figure out to what torque I should limit this shaft to in operation.
Environment info:
between 5-10 degrees C
To make sure you are clear, the shaft we are using is made of 440C but we will be switching to 17-4 PH in the future...however I am hoping I can stop this from happening before the shafts get made...as I believe these shafts will not hold up...
Thanks,
Tom
RE: SS 440C
All the 17/4 we use is treated to at least to H1100 based on our original work coupled with ARMCO’s recommendations many years ago. Aside from the problems with 17/7 the only problems with 17/4 and 455 has been temper embrittlement after exposure to 600°F and occasional excursions to 900°F. This shouldn’t affect your application at your temperatures.
We actually used Aquamet 22 or Aquamet 17 for our RW pumps and CTW pumps in place of the original 416 SS with tremendous results. It comes TGP and straight in box ready to use.
We use a lot of 17/4 and 22/13/5 for boat shafting with not problems. I have a 3" x 11' Aquamet 17 (17/4 H1125) shaft on a boat that I have an interest in. Nearly all the local shipyards use Aquamet 17 on boats, even for Alaska. I seen some that had sheared in the coupling or prop but no brittle failures.
RE: SS 440C
If you are seeing any plastic deformation (and if your lab says they see ductile overstress failure mode), then you can use the von Mises yield criterion to analyze your shaft. Your equation is proper for this analysis.
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: SS 440C
nominal max torsion stress = (16/(pi*d^3))*(M^2+T^2)^0.5
d = shaft dia
M = bending moment
T = torsion load
On top of this you must consider:
Stress raisers such as shoulder fillets & keyways
Surface finish factors
Size factors
Temperature factors
Reliability factors
Overload factors
120 ksi is an extremely high shear stress level for dynamic loading, for any alloy, especially if you have not yet considered the above list of factors.
A thorough treatment of the subject can be found in Shigley & Mischke's Standard Handbook of Machine Design, MCgraw-Hill.
Phil Rockwell
pdr@baymachinedesign.com