O1 vs 80CrV2

This is a great article as always. I may chine in a littlebit since I have some experiment on 52100 using low temp molten salt equipment.

The steel being use is bohler R100 shich pretty much identical to 52100.

All pieces has been thermal cycle normalizing and hardening by austenitizing at 1525F and soaked for 15 min.

The first coupon ate quenching from austenitizing to lower bainite range (425f) and hold it for 3 hours.

Another one are quenched to below martensite start point (385F) and holdit for 2 min and later forced air cool and then tempered at 415f. Both are test at around 61HRC

For some reason the edge holding of the bainite piece are significantly lower than the later piece ... even at the same HRC and similar hardness. Just my observation tho.
 
shqxk said:
This is a great article as always. I may chine in a littlebit since I have some experiment on 52100 using low temp molten salt equipment.

The steel being use is bohler R100 shich pretty much identical to 52100.

All pieces has been thermal cycle normalizing and hardening by austenitizing at 1525F and soaked for 15 min.

The first coupon ate quenching from austenitizing to lower bainite range (425f) and hold it for 3 hours.

Another one are quenched to below martensite start point (385F) and holdit for 2 min and later forced air cool and then tempered at 415f. Both are test at around 61HRC

For some reason the edge holding of the bainite piece are significantly lower than the later piece ... even at the same HRC and similar hardness. Just my observation tho.
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That's somewhat unusual. How was edge holding measured?
 
There’s a lot of mysticism regarding bainite. This might be a good article topic to clear up fact from fiction. I’ve thought about bainite, but never attempted to make a blade that way.
 
Willie71 said:
There’s a lot of mysticism regarding bainite. This might be a good article topic to clear up fact from fiction. I’ve thought about bainite, but never attempted to make a blade that way.
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An article on bainite is definitely on the list. I've gathered quite a few journal articles for it. But as I said in this most recent post it's somewhat disappointing what is available. It would be nice to do a toughness study with someone who has salt pots.
 
Larrin said:
An article on bainite is definitely on the list. I've gathered quite a few journal articles for it. But as I said in this most recent post it's somewhat disappointing what is available. It would be nice to do a toughness study with someone who has salt pots.
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I’m not set up for salt pots yet. I’ve got three other projects for equipment to get to first.
 
I know most people are concerned about fixed blades, but what about slip joint springs? Or other parts made to bend? Would an austempered O1 spring be "better" than a traditional quench and temper (at 675 degrees)? I am not really sure what i mean by better. Suppose a traditional tempered spring and an austempered spring have the same hardness (i am not sure if this is reasonable), would the austempered spring experience less wear against the blade tang and have a higher young's modulous?

Also, for spring parts there are significant variances in the dimensions from one end of the spring to the other, unlike most blades. The pin holes in springs can be the weak point of a spring, and blades usually dont have holes in them. So the austempering, and the reduced stress, also seems to be an advantage for springs. What are your thoughts on this?
 
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I use the coupons to cut some 2x4 and cardboard. The bainite piece has rather low edge holding.

In contrary the marquenching piece has much noticeably better edge holding than conventional queching.

Digital control low temp salt pot is very popular equopment among knifemakers here. There is a tool maker who make and sold them for $700. There are over 20 of it has been sold. Every makers who use salt pot reported to have the same experience on the improvement in performance. We use it for tempering too.

Actually the 52100 with conventional quenching and 415f tempered are HRC test at 59-59.5 HRC. The marquenching piece with same tempering are tested at 61HRC.
 
The winner of Knife or Death last night on History had a sword, the first that did not bend nor suffer major edge degredation.
He was asked about his heat treat method; austenize in a salt pot and then quenched in a salt pot at 400 degrees for an hour.
If I understood your article correctly, this was a Bainite sword?
Please correct me if I'm wrong.

My next question for Larrin is,
Is the Bainite method only good for low alloy oil hardening carbon steels or can the method be used on higher alloy air hardening steels.

Bainite choppers and swords are something that has interested me for a few years, but is something I have never had the opportunity to play with.

Thanks
 
Big Chris said:
The winner of Knife or Death last night on History had a sword, the first that did not bend nor suffer major edge degredation.
He was asked about his heat treat method; austenize in a salt pot and then quenched in a salt pot at 400 degrees for an hour.
If I understood your article correctly, this was a Bainite sword?
Please correct me if I'm wrong.
Click to expand...
That heat treatment would very likely result in a primarily bainitic microstructure.
My next question for Larrin is,
Is the Bainite method only good for low alloy oil hardening carbon steels or can the method be used on higher alloy air hardening steels.

Bainite choppers and swords are something that has interested me for a few years, but is something I have never had the opportunity to play with.

Thanks
Click to expand...
Bainite transformation is slow or non-existent with air hardening steels so they are not ideal for bainite.
 
Big Chris said:
The winner of Knife or Death last night on History had a sword, the first that did not bend nor suffer major edge degredation.
He was asked about his heat treat method; austenize in a salt pot and then quenched in a salt pot at 400 degrees for an hour.
If I understood your article correctly, this was a Bainite sword?
Please correct me if I'm wrong.

My next question for Larrin is,
Is the Bainite method only good for low alloy oil hardening carbon steels or can the method be used on higher alloy air hardening steels.

Bainite choppers and swords are something that has interested me for a few years, but is something I have never had the opportunity to play with.

Thanks
Click to expand...

Do you remember the contestant name? He made the sword? That show hasn’t arrived to History channel Portugal yet. I believe you’re right and it is bainite.
 
IIRC, Verhoeven talked briefly about quenching to get like a 10% bainite/90% martensite structure. I am not sure if that brings any advantages. I also recall Howard Clark saying that he was not going to give away his method for getting a bainite body and martensite edge with L6, but "the information you need is out there." Of course, this is coming from a mad scientist who does nominally insane things like austenize clay coated blades in high temp salt, so your mileage may vary. :eek::D
 
hugofeynman said:
Do you remember the contestant name? He made the sword? That show hasn’t arrived to History channel Portugal yet. I believe you’re right and it is bainite.
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Michael Allenson I do believe was his name, and yes he made it himself.
 
jdm61 said:
IIRC, Verhoeven talked briefly about quenching to get like a 10% bainite/90% martensite structure. I am not sure if that brings any advantages. I also recall Howard Clark saying that he was not going to give away his method for getting a bainite body and martensite edge with L6, but "the information you need is out there." Of course, this is coming from a mad scientist who does nominally insane things like austenize clay coated blades in high temp salt, so your mileage may vary. :eek::D
Click to expand...

He marquenching the whole piece in salt pot and soak to get the bainite structure first and then do a different hardening by acetylene torch and quench into low temp salt again with set up equipment but this time just a minute soak and then air cool.

Good thing is when we start austenitizing and quench from bainite strucuture the martensite we got seems to be finer and tougher.
 
Interesting. I think that I may have discussed this with Hoss and/or Larrin on here before, but I was worried a tiny bit about what the "transitional" area of the blade might look like when you use a differential HT method like that. I was wondering about it in the context of making a bainite tactical tomahawk out of L6 and then going back and "requenching" the edge of the bit and the tip of the spike to get martensite.
shqxk said:
He marquenching the whole piece in salt pot and soak to get the bainite structure first and then do a different hardening by acetylene torch and quench into low temp salt again with set up equipment but this time just a minute soak and then air cool.

Good thing is when we start austenitizing and quench from bainite strucuture the martensite we got seems to be finer and tougher.
Click to expand...
 
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