4340 vs 8620

[Little Mouse]

4340 steel looks like it would be better for making a camshaft out of then 8620. Is this correct, do they make 4340 steel camshafts ? If not why ?

[digger]

8620 is cheaper and normally case hardened is good enough

[Rick!]

My best recollection is that 8620 has better machinability after heat treatments, potentially better yield strength, and a bit better elongation. I used it for power transmission shafts on gas powered toys. The next level of heat treatment (Q&T) gives even better strength but will cost a bit more in machining tooling (bits, etc).