............would it need to go through a heat treat process?
It would not be considered mandatory, but, back when we used O.E.M. cranks in performance applications we would get them nitrited; this after turning, a ruff polish, heat treated, then straightened, and this would sometimes be concerning as to the sum of re-alignment required, then finish polished.
The heat treatment facility (Sun Coast) was just down the road less than a mile from our shop which was convenient, but every once in while our stuff would come back bright marbled purple in color, I always assumed do to some contamination of the atmosphere in treatment, or it's what happens when late in the day the employee wanting to go home swings the containment door open to soon instead of waiting for the adequate cool down period. We never experienced any issues with this, even though one was still left with the concern for inconsistency in appearance and therefor execution; but with the advent of the 4.6 Modular steel cranks, they most often appear with the same purple coloration, so what the heck!
Scott.