No heat treat at all, this was a simple, no frills bow.  I have thought about heat treating it, but would have to get a gun.  I am trying to keep my bow making simple for the time being.  I think the hinge is from early tillering, it isn't real clear when drawn, but is definitely there when unstrung.  I have another board of ash (the mate to this one), I am going to try a bit shorter, and wider.   This one is just over 1 1/2 inches at the handle, to about 12" from the nocks.
Kyle