Sorry! I suffer from acronym syndrome sometimes.
CPM is the trademark of Crucible Particle Metallurgy, who makes the CPM440V steels used in Spyderco's Chinook and Military for example, and also makes the new S30V super steel.
There are limits to what amounts of alloying agents will stay in solution in a molten steel formula. High alloys tend to segregate during the ingot cooling process. Crucible developed a proprietary process to make alloys that were not subject to the limitations of normal molten phase steel.
They do this spraying molten steel through a small nozzle and gas atomizing it to produce a rapidly solidified fine powder. The powder is screened and filled into steel containers which are evacuated and sealed. The filled containers are then hot-isostatically-pressed (HIP) to achieve 100% density at approximate forging temperatures. This allows them to produce new high alloy grades only available via the CPM Process, and make steels with better wear resistance without sacrificing toughness.
" name="Crubible">Here's a link to Crucible's S30V data sheet</a>
In that link, you will see comparisons to 154CM - that is almost identical to ATS-34. The main difference is that 154CM was an early Crucible product, and ATS-34 is made by Hitachi Steel. For comparison purposes, you can use the 154CM data.
I got these lines in my face from trying to straighten out the wrinkles in my life