Bainite heat treatments of 52100, O1, and 1095

Larrin

Larrin

Joined
Jan 17, 2004
Messages
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New article summarizing some experiments I did on “austempering” for bainite of 52100, O1, and 1095. There were some interesting results about how bainite gest improved toughness of typical tempered martensite. I also compared between the high carbon steel heat treated for bainite vs high toughness medium carbon steels. And offered some opinions about getting setup for austempering vs sticking with a typical quench and temper. https://knifesteelnerds.com/2021/06...ents-of-52100-o1-and-1095-how-much-toughness/
 
Another great article. Glad to see you actively pursuing insight. Your interpretations seem reasonable.
 
Another article that really caught my attention. I'd been reading about this "Magical" method of HT'ing and wanting to try it myself, but as you said it does take a bit of equip expense. You've answered my questions nicely - THANK YOU
 
My early bainite experiments with 1095 did not get results that showed an improvement over Q&T. 52100 was what got me interested again. MY preliminary testing and theoretical projections seemed to be in line with what you found. 52100 gains a lot of toughness while retaining most of its hardness. I also found a mixed structure of martensite and bainite beneficial. I plan to continue these when the new shop is fully powered and I can run both salt pots. Those things draw 7200 watts each. If I have the temper oven also running I am pulling over 17,000 watts, or around 70 amps. Run those for as many as 4 hours straight and it will spin the meter as well as heat up the shop wiring.
Back to bainite.
I found a 30-50% mix of martensite/bainite in the 52100 seemed to gain hardness with very little drop in toughness over 100% bainite.

Interesting trivia - Bainite was originally used for high toughness shafts and other parts in Rolls-Royce cars and in the frames of railroad cars to reduce stress cracking due to the flex of the frames as the cars go down the rails.
 
Super interesting article. You keep poking holes in all of our mysteries. Next you are going to tell use that edge packing and quenching towards magnet north don't make any difference. You forgot one if the biggest advantages to bainite though. It just sounds cooler and it's not like you can just go get a bainite knife. Super cool research though. It sounds like it would be really interesting to mess around with some if the mixed structures for some long chopping blades. Heck even if they are only just as good they are still special and sometimes that's important.
 
That was a great article.
 
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