I have a box of 15n20 that I got from JD. I think I might do a run of knives with it. I have had great success with it just using my atlas forge. Now that I have a oven I want to up my heat treatment quality. I don't have parks 50 and so I will use the old canola oil. This got me to thinking, if you have a simple carbon steel and are not giving it a fast enough quench, will cryo possibly help complete the conversion process?