"try"? If it's harder than your skin it means it did, not tried.
It may have gotten a nibble but empirically I still have a finger :)
A steel door is certainly harder than my skin and also certainly can't be used to "bite" me or puncture my skin (save for crushing it given enough force)
Just because it's harder doesn't mean it necessarily has the strength to tear off skin.
Just because you succeeded doesn't mean you didn't try.