It's hard to tell exactly which type of steel you have. I have no problems working with unknown steel, but you have to experiment a little, first.
Take some smaller pieces and try the heat treat and temper and see what they do. do you get good flex? is it soft enough without being too soft? - Come back for suggestions on adjustments if you need to.

- make a couple 6-8 inch minimachetes
For the blade
You won't get a full proper textbook anneal, but if you try using the heat/vermiculite or heat/wood ash methods, you should get it soft enough to work well.
Noting that I'm NOT a mastersmith, what I'd do is this:
heat to a little above critical (aim for non magenetic) and hold it in the tongs until it's black, then heat again, a bit more, and try and get it as straight as possible with the hammer. Then heat to just above critical and put it in a bucket/barrel (I use a metal trashcan) full of vermiculite. Let it cool for about 8-12 hours or however long it takes to reach ambient.
Then you are good to grind.
***note that this isn't a specific annealing process for a given known type of steel, but should get you something you can work with with just about any steel I can imagine being used for leaf springs.
Grind away, then for heat treating you'll have the straightest results if you follow a normalizing procedure 3 times, then run your quench and tempering cycles. For machetes I've mostly stuck to 1080/1084 steels with an interrupted quench to make sure I get things straight. The normalizing is really, really critical on these types of blades.