shaft material choice: stainless 1

[abeschneider]

I need to specify a shaft material for the following application:
* submerged in freshwater
* Max torque 320 N-m(~3000 in-lbf)
* Continuous duty
* Will have plain bearings mounted on it (probably the bearings will actually reference against special shaft sleeves, not on the shaft itself)
* Will have roller-chain sprockets with keys mounted on it

I'm thinking a 416 Stainless Steel, Condition T (ASTM A582), hardened to ~30 Rockwell C; Tensile Strength: 758 MPa; Yield Strength 586 MPa. Material data can be found here:

http://www.azom.com/details.asp?ArticleID=971

Is there a better choice, that would supply similar properties at a better price, and be easy to machine?

Thanks...

 

[mm87vt]

No need for any high end corrosion resistant alloys. The Aqualoy 17 material (17-4PH H1150) will do very well in freshwater, and, it is far superior to 316 stainless or any 300 series stainlesses in terms of strength. It has approximately 3 times the torsional strength of type 316. Good luck.

 

[Artisi]

Have a look at 2Rk65 from Sandvik

 

[Cheddarcaveman]

Good old 4140! Used it just about everywhere and as long as it spends its time submerged it won't rust. A lot of boat prop shafts are from this. It's easy to machine, won't gall, will take loads of torque and is probably a lot cheaper than all those exotic stainless shafts.