The strongest fixed I own hands down has to be my Medford .30 thick fixed blade it is in CPM 3v, I have never had an s7 blade, I am assuming most s7 blades with good heat treat would be all you need. Not to be annoying, but I don't think folding knives are "strong" in general, it is good for what it is designed for but I am appalled some people buy "strong" folding knives to cut cardboard and call it "hard use" come one now.