easiest way to tell if a piece is worth trying to make a knife out of is the hardening test. take a small piece of it & heat it until a magnet wont stick to it and get it just a little bit hotter, then quench it quickly in the largest vat of oil you got on hand (one of those disposable alum. turkey roasting pans with a few inches of canola, used motor oil, tranny fluid, etc.) once completely cooled. then don all yer safety gear (eye protection-full face sheild, heavy gloves, etc.) clamp the end of it in vise and whack the other end with a hammer.
if it snaps cleanly or shatters, it hardened well and is worth trying. if it simply bends over, then you gotta try another heat and using a faster quench like water (but only after doing the oil test first....some oil quenching steels will rip themselves apart violently if quenched in water)...still not hard?...then make something else outta it