Need UTS &Yield on 4150 Large dia bar

[sprintcar]

I'm trying to get specs on 16" diameter, 4150 steel, nonresulfurized. All the specs I can find end at 8" dia which shows about 115 ksi ultimate tensile, 85 ksi for 0.2% yield. Our vendor couldn't do any better.

Any easy way to estimate the change as bar size grows? It appears to lose about 5 ksi per 2" diameter increase, but I doubt this is linear.

HELP!

Keep the wheels on the ground
Bob

 

[emery]

Bob, Minimum expected longitudinal mechanical properies at mid-radius of the round bar or shaft for 4150, normalized and tempered to 220/260 BHN, for a steel forging of 8" to 24" dia. is 109,000 psi tensile and 74,000 psi yield,
elongation 19%, R.A. 42%.
What is the heat treatment on your piece?

 

[sprintcar]

Thanks Emery!
Not sure what the final heat will be - I think it was spec'd at about the hardness you referenced - this was info a customer requested to do more meaninless calculations on a preliminary design.
I have recommended that we look at using 4340 when the shaft gets above 8 > 10" range - a bit more $$ but less risk.
I asked our vendors and they couldn't come up with anything, so you are definitely the MAN today!
Thanks again Keep the wheels on the ground
Bob
showshine@aol.com