In the past I made a bunch of knives out of old ford springs........worked just fine.
If you have a forge it's not hard to figure out a good heat treat procedure.
Make an educated guess as to proper HT procedure, try it, and then test cut with the blade. Use it hard and then break it to see what the grain looks like as well as how tough it is to break. Keep notes of all the heat treat steps you do so you can repeat it or tweak it until you are satisfied with the results.
Have fun.
Darcy