...So ideally, you are trying to get as much austenite as you can in the start of the quench, then turn as much of that as possible into martensite as you get past the nose, and then relax the martensite by letting the carbon move slightly in the tempering process?
And this slight carbon movement creates tiny, stable carbides in a tough matrix?
Sorry for the many questions, but I am thrilled to have the chance to learn some of this the right way.
Well generally- yes. however there is a reason I continually harp on the idea that none of this is all that simple and can ever be handled with one or two simple recipes.
What you are shooting for when austenitizing is to get from .60% to .80% carbon into solution so that you can get maximum martensite hardness while leaving the extra carbon tied up in very fine and evenly distributed carbides, for excellent wear resistance. Beyond this more dissolved carbon will result in heavy amounts of embrittling plate martensite (don't worry about it too much as it would require another thread unto itself) and encourage retained austenite.
This is the ideal, but what gets in the way is the initial carbon content and the ammount of alloying elements that will grab onto carbon and not let go and this is why each steel has its own austenitizing temperature and the time required for it to work. Simply using a nonmagnetic for everything will get you in the ball park but will never get you any home-runs.
1080 or 1084 is mostly just carbon to get into solution so heating it to nonmagnetic for even a short time will yield pretty good results, however simply add some chromium and remove around .2% carbon and now you will need to go all the way to 1525F and hold it for some time in order to break the bonds with the chromium and dissolve the extra ferrite in order to get things all in solution and evenly mixed for the quench. If you get the solution you are looking for, then quench it and lock it in! If it all goes right you will have a matrix of fully hard martensite with some acceptable ferrite that is evenly filled with very fine chromium carbides.
If done right this stuff will be brittle and you dont wnat to mess around too long with it in that state. Tempering it will take enough of that carbon back out of the supersaturated solution and toughen the matrix as well as allowing even more nice little abrasion resistant carbides to form.
It sounds like a lot and too much to handle, and it is if all you have is a magnet and a bucket of oil and your best guess, it probably is. But the folks who designed that steel already worked it all out for you and put it in print for anybody who wants to give it a try. Bladesmiths are really makig it hard on themselves by dismissing this information and insisting upon reinventing the wheel with really odd practices.
NEVER apologize for asking questions in these discussions, that is the only way all of us can really work through this and learn. This includes myself, I use these discussions to work things out clearer for me and if there were no questions to cause us to think my initial post wouldn't be of much worth. I owe you a thank you for keeping the conversation on a strong constructive path.
