Commonly known as spring steel, 5160 has excellent shock absorbing properties making it resilient to shattering and extremely durable as a knife steel. We harden to 57-58 Rc to maximize its performance.
I carry the Buck folding saw in my mountain bike pack everywhere I go. I've probably removed 30+ downed trees from trails over the past 15 years with it. It's never been sharpened and still cuts like a hot knife through butter through any tree 6" or less in diameter. Folds up to protect itself and your pack when not in use. Light enough to live in my pack all year.