Para,
My understanding of the CPM process pretty much follows along the lines of what you've described. The steel begins the process in a molten state very similar to that which is seen in conventional steel making, except that the CPM steel contains higher levels of carbide forming elements than can be supported using conventional methods.
The molten steel is then sent through a nozzle and essentially atomized such that a flash hardened powder of 'micro ingots' result. Because of the small size of these individual powder particles, and the speed in which these particles freeze, the alloying elements don't have time to segregate and clump together as would happen if the steel was poured and allowed to cool in larger ingots. Not only are the carbide grains more evenly distributed throughout the steel, but they are also smaller in size.
These individual powder particles are then recombined using the hot isostatic pressing (HIP) process, a high pressure treatment which, interestingly enough, subjects the steel to temperatures very close to those which are encountered in forging. According the folks at Crucible, the fine grain structure and even distribution of the carbides within the steel are preserved through this process. It may well be the case then, that this fine grained, homogenous steel is able to survive similar treatment at the knifemaker's forge.
As to the question of the quenching process, Crucible recommends the following for 420V:
"Salt quench, interrupted oil quench, positive pressure gas quench or air cool at a minimum cooling rate of 150F/min to below 1000F followed by still air or moderately forced air cooling to below 125F".
I doubt this answers all the questions, but it's a little more data for the discussion.
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Semper Fi
-Bill