Eagles method is how I would do it. You can also anneal saw blades or files in a fire. Place it in a fire and leave it to cool in the ashes overnight. Some do the fire outside and when the steel reaches cherry red, bury the fire with earth. When cool it will be workable with hand tools. The important thing here is to cool the blade slowly. Or just buy a $10 Ulu, probably made in China but the one I have as a kitchen knife is made from 440c and holds an edge very well.