Good question. I would think that if it did, it would only be a concern with steels of the 10XX types that require a very fast cooling quench. There is little need to use it on those as most leave them a bit over sized anyway to prevent cracking, and they will need more grinding after the temper. 10XX steels do not require any lengthy soaking at high heat so decarb is not a great concern either. I use ATP on a regular basis for 01, and it has no effect on it. When it comes out of the oil it is shiny smooth and there is no decarb. The ATP allows me to take my 01 blades to finished dimensions, and only requires a simple clean up to get them ready for the grip.