Need some clarity on heat treating Bohler D2 (k110)

seelow123

seelow123

Joined
Oct 4, 2008
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Good evening everyone. I tried to get this info through the stickies but couldn't find anything that pertained to this particular type of steel.

I have a Medium/small fixed blade I made out of .098 thick Bohler D2 which I understand is actually called k110? I really need some step by step info on how to heat treat this blade. I have looked and a bunch of different sites but the info is always a bit different so I though I'd ask here.

I use an Evenheat KH 418 to heat treat. I only have some vegetable/canola oil to use as quenchant. I would really like some step by step instructions on how to properly heat treat this steel. Temperatures, soak times, tempering cycles/times/temps etc.

I really appreciate any info you guy can give me.
 
Alpha Knife Supply has detailed HT info on their web site.

Also, Bohler has detailed info on their site

You'll need some stainless foil wrap...USA Knifemakers supply has it....use the high
temp version.

D2 is an air hardening grade tool steel.
 
I used K110 D2. Here is my HT. Wrapped in Stainless foil. Ramp it up to 1500 and hold for 20 min to stabilize oven heat and preheat the steel. Then I go to 1800 and hold for 10 to even out the oven and then go the 1850 and hold for 35 min. Then I plate quench between large aluminum plates, steel will work, as would copper or brass. Wearing heavy gloves, I cut foil packet with heavy sissors and slide blade out around 600 and check for straight and tweak if nessecary. Then water cool and into a bucket of dry ice/ethenol (or kerosene or acetone) for 1/2 hour, then into oven at 425 for 2 hrs, then back into dry ice slurry for 1/2hr then back into oven for another 2 hr 425 temper. Should be between 60-61RC

Get the blade very close to where you want your finish, grinding is tuff and sanding is really tuff after it is hard. Jim
 
I just heat treated some D2 and I have the same oven as you. Wrap using high temp foil wrap with double seams with a small piece of paper inside. Get you some 1" thick aluminum plates for your quench. I turn my oven on and set it to full ramp to 1850. I put my blades in at about 1500. Let them soak at full temp about 15 minutes and then quench between your aluminum plates while you stand on them. Do not worry about taking the knife out of the foil to quench. I tempered in my home oven at 400 twice and got a 60 Rc on all 8 blades I did.

Good luck.
 
Russ Andrews said:
Alpha Knife Supply has detailed HT info on their web site.

Also, Bohler has detailed info on their site

You'll need some stainless foil wrap...USA Knifemakers supply has it....use the high
temp version.

D2 is an air hardening grade tool steel.
Click to expand...

Thank you Russ. I'm still a bit confused. Since it's an air hardening steel do I just take it out of the oven and let the air do it's thing? The info I got from Bohlers site says to bring the oven to about 1870 degrees and leave it in for 15 to 30 minutes. I would like the blade to be about 60-61 hrc so I'm thinking I should leave it in for about 23-25 minutes? then temper twice at 392 degrees?

I know there's a lot of questions there but this is my first time working with something other than 01 or 52100 so it's new to me.

Thanks again.
 
Thanks gents! That's a ton of good info there. Is the purpose of the foil just to prevent decarb? Do I have to use aluminum plates? I plan on getting some plates here soon but not right now. I would like to get this blade done this week but if I really needs the plates to create a good working blade I can wait till I get some. Could I just let it cool in the air after I take it out of the oven or quench it in oil? Again, I really appreciate all the info you guys have given me so far.
 
If you have anything that is thicker and stiffer than the steel you are heat treating will be a bonus. You could just let it air cool, but by using the plates you get a straightening effect and the faster cooling ensures the blade gets harder.
 
Big Chris said:
If you have anything that is thicker and stiffer than the steel you are heat treating will be a bonus. You could just let it air cool, but by using the plates you get a straightening effect and the faster cooling ensures the blade gets harder.
Click to expand...

Okay, that makes sense. So they don't have to be aluminum but the aluminum helps cool the steel faster. any two pieces of flat metal that are thicker than the blade will work? How much softer do you think the blade will be if I don't use the aluminum? Could I compensate by tempering for a shorter period of time?
 
Steel companies used to recommend quenching D2 in still air....it does work.
Using forced air would be a bit better, and plate guenching would be better still.

Plates should be the same size and type of material. to pull heat evenly form
both sides of the blade.

Freeze treating is a definite asset, but D2 can make a very fieldworthy blade
even without it.
 
I may be wrong but one thing I think you are missing is how times and temps. work. The soak time at the hardening temp. shouldn't be shortened to reduce the hardness. The soak time is to allow all the elements to go into sloution and shortening the time will effect the quality of your heat treat. Your tempering times should also be the same no matter the temperature. Tempering temperature is what determines hardness not the amount of time at that temperature. One thing to remember when working with any new steel is to temper on the low side and raise the temp. as necessary to get to the proper hardness. You can always raise the temp. and re-temper to reduce the hardness but in order to raise the hardness you have to re-harden and start the process all over. I hope this makes sense.
 
Russ Andrews said:
Steel companies used to recommend quenching D2 in still air....it does work.
Using forced air would be a bit better, and plate guenching would be better still.

Plates should be the same size and type of material. to pull heat evenly form
both sides of the blade.

Freeze treating is a definite asset, but D2 can make a very fieldworthy blade
even without it.
Click to expand...

It's all starting to make sense now. I'm much more confident in my abilities now that you guys have helped me out. Thanks again everyone!

darrin sanders said:
I may be wrong but one thing I think you are missing is how times and temps. work. The soak time at the hardening temp. shouldn't be shortened to reduce the hardness. The soak time is to allow all the elements to go into sloution and shortening the time will effect the quality of your heat treat. Your tempering times should also be the same no matter the temperature. Tempering temperature is what determines hardness not the amount of time at that temperature. One thing to remember when working with any new steel is to temper on the low side and raise the temp. as necessary to get to the proper hardness. You can always raise the temp. and re-temper to reduce the hardness but in order to raise the hardness you have to re-harden and start the process all over. I hope this makes sense.
Click to expand...

That does make sense Darrin, thank you for clarifying that for me:thumbup:
 
Here's what I'm thinking about doing with the Heat treat. Just throwing this out there so you gents can warn me if I'm doing something wrong.

1. heat the oven to 1850 degrees. place the blade in the oven at 1500.

2. soak the blade at 1850 degrees for about 15 minutes.

3. take blade out of the oven and place between to thick metal plates that are even in size and stand on them. Should I have a fan going on full blast pointing at the plates while doing this just because?

4. temper the blade at 400 twice. Should I have them in there for two hours each time?

I think that's all the questions I have for now haha. Thank you all very much for your information.
 
That looks good. No fan is needed but wont hurt anything. Both tempers should be 2 hours. If at all possible, test the blade after tempering and if it chips out at the edge, raise the temp. to 425 and temper again to reduce the chipping.
 
darrin sanders said:
That looks good. No fan is needed but wont hurt anything. Both tempers should be 2 hours. If at all possible, test the blade after tempering and if it chips out at the edge, raise the temp. to 425 and temper again to reduce the chipping.
Click to expand...

Perfect. I will do the HT tomorrow. Thank you sir
 
Hallo, i have some question. How about hot oil quenching for k110? Is it work or not? Or its could make the k110 easy to break?
 
kswarchery said:
Hallo, i have some question. How about hot oil quenching for k110? Is it work or not? Or its could make the k110 easy to break?
Click to expand...
Hardening K110 in oil will make it too hard and brittle, I did it on test blades. You need harden it on air. I used forced air (I used bathroom ventilator) in steel "chimney" and I got good result.
 
Jesenius said:
Hardening K110 in oil will make it too hard and brittle, I did it on test blades. You need harden it on air. I used forced air (I used bathroom ventilator) in steel "chimney" and I got good result.
Click to expand...
Ok... thanks alot... i'll try it...
 
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