High Temperature Shaft Material

[Tablet]

Does anyone have experience with shafts at High Temperatures
I am rotating a shaft at 4500 RPM inside a 1200F environment. Current shaft is A2 steel, 1.5" Diameter with a light cantilevered load.
Shafts are bending enough to create balance issues with some corrosion. I was considering switching to a 310 SS and using current design (short term solution) and maybe redesigning , increasing diameter or redesigning using hollow shafting.

Tablet

 

[TVP]

As you have discovered, A2 is not appropriate for such high temperature use. Type 310 or 347 SS is a more suitable option.

 

[arunmrao]

Agree with TVP 310 is a good material and lasts long. One example that comes to my mind is the fan used in seal quench furnaces. The fan is 330 and shaft is made of 310 grade stainless steel. Hope it helps.

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

 

[EdStainless]

Unless you can live with 20ksi yield strength at 1200F in 310 you need a better option.
My guess is that this is no stronger than what you have now.
If you get a cold finished shaft for higher strength you will stress relive it in service.

There are a number of Ni alloys that will offer high strength at 1200F.
625 will still have over 50ski yield at that temp.
If you want more try 718 age hardened, you will be 150ksi.
But they will be stupid expensive.

More practical would be a hot-work tool steel, like H-13.
Have it tempered at 1250 or 1300 and just move on.

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Plymouth Tube

 

[metengr]

First, there is not enough information to select a material or even guess with what you provided. What are the design loads? You need to first determine the following - starting torque, from there determine bending stress and torsional stress at service temperature. Once this is completed, you can review material options based on needed strength level and creep, and then decide on a suitable material with adequate design margin.

 

[Screwman1]

With the H-13 material be careful to watch out for notch sensitivity and stress corrosion cracking.

 

[EdStainless]

At this tempering temp the hardness of H-13 will be RC 30-35.
I would not worry about lack of ductility at this condition.

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Plymouth Tube

 

[Screwman1]

Duhh! Forgot the tempering effect! Need more coffee.

 

[Tablet]

Thanks for your Help, I have to get unit back in service for the short term while dissecting the design as suggested and redesigning wit proper MOC's