Annealing 1080 twice, got a softer edge than expected

I tried annealing a batch of 1080 blades twice before hardening, figured double the soak would make them easier to grind. First one came out of the quench with an edge that dulled on a pine board in about ten cuts. Is there a reason double annealing would leave excess ferrite, or did I just mess up the soak times on my propane forge?

2 comments

2 Comments

kim.sandra25d ago

That "cooked the ferrite right out" bit caught my eye, because I've seen guys chase that same ghost. If you're running a forge without a digital readout, you're basically guessing at soak temp, and 1080's sweet spot is narrow. But here's the thing I gotta ask, when you did that double anneal, did you let it cool all the way down to room temp between cycles, or did you just drop it to black and reheat? Because if you went straight from the first anneal into the second without a full cool, you might've left some weird internal stress that showed up after quench. And what did your grain look like on the break test, fine like a nail file or kinda coarse and sparkly? That'll tell you way more than any hardness tester if you ask me.

stellafisher26d ago

That sucks, man. Pine is a brutal test too, it's got silica in it so it'll eat any edge without a super steep micro-bevel. I had a similar thing happen on some 1095 when I got impatient and cycled it too many times, ended up with a grain structure that just wouldn't hold up. Maybe check your soak temp with a thermocouple, those propane forges run hotter in the back than you think, and you might have cooked the ferrite right out but softened the matrix some other way.