Leaf Spring into Machete

I have an old leaf spring that I would like to make into a machete.I know I will have to heat and straighten it,that is no problem,,I have the equipment,the problem is the proper heat treating and welding/brazing after straightening.I presume the spring steel is high carbon steel, so welding would be unreliable,so I will drill and rivet the handle hardware.

Can someone give me the proper heat treating procedure to give a hard but tough blade that will hold a good edge?

Thanks.