Crankshafts - Forged vs. Billet

[Pantaz]

I understand that forged crankshafts are generally accepted as "stronger" than billet (machined from solid) cranks. But, I am trying to compile more specific information.

Any information sources on comparative features, such as fatigue resistance, wear characteristics, etc.?

Thanks!

 

[swall]

I assume that you understand that the superior mechanical properties of forged cranks are due to the grain flow in a forging following the linear contour of the crank. Some of these other properties such as enhanced wear resistance can be achieved with both forged or billet cranks, since supplemental treatments, such as nitriding, can be applied to either. Ditto for fatigue, although with a forged crank you are starting out with an advantage. Supplemental treatments for fatigue enhancement, such as fillet rolling, induction hardening of the fillets, and shot peening can be applied to billet as well as forged cranks.

 

[jkm333]

Lets not forget that there are many variables besides crankshaft heat treating, journal chroming, shot peening, tuffriting, etc. to consider. For instance - material selection and twist or non-twist forgings are two big ones.

Josh