Relationship between metal fatigue and stress hardening

[Mark Reich]

With a metal that can be work hardened, is it possible to have metal fatigue/failure without hardening happening?  Is one always indicative of the other?

Is this a sensible question?

There aren't any nonsensical questions on this site! 

However, I may not always understand the question.

I understand wood scrapers plenty well, but I've never had any issues with them. I probably burnish the hook half a dozen times or more before truing the edges, and I've never seen a chip.

It's pretty rare to hear about work hardened knife steel too, and I can't say I've witnessed it. What type of application are you wondering about? Are you wondering about a specific steel or instance?

Jan, Welcome to the forum, it's great to see you jump in with your knowledge here! I've never heard of a Deborah number. From a brief search I could see that knowledge might be beyond my pay grade.

Great thread guys!