Heat treating O1 Steel and grain growth

I get asked quite often about heat treating O1 tool steel. While it is relatively simple in annealed flat section forging brings with it some challenges.
If stock removing from flat bar (or round bar if you hate yourself) heat the O1 after machining to 815 Degrees Celsius and hold for around 10 minutes. Quench into medium speed oil and then consult a tempering diagram.
If forging try to keep the steel between 1065 and 845 Celsius. To correct grain growth I try to follow this schedule:
Heat to 900 and then cool to black heat
Heat to 830 and cool to black heat
Heat to 700 and cool to black heat
To harden soak steel at 815 degrees for 10-30 minutes and quench into medium speed oil.
In the video I show what happens in 2 forged sample pieces. One is quenched too hot with no grain refinement or normalizing. The other follows the formula described above as best I could manage with the camera work. The difference is pretty stark. For a more in depth explanation of the forces at work while forging / heat treating this steel check out these pages www.iforgeiron.com/topic/3875...
www.cashenblades.com/steel/o1....
To source O1 steel in Australia see this link:
www.artisansupplies.com.au/pr...

[@Jeffrose_]

Great video. I plan on using 01 steel for all of my knives. I think thats how i found your video. Very helpful for me thank you

[@64t120r]

Good video. I appreciate you showing the difference visually.

[@batcountryforge5945]

64t120r Thanks! Always good to give it a go yourself too. Reinforces the learning.

[@Turin-Fett]

Good stuff. I tried making a pipefitter's wedge out of some mystery rail car spring a while back. Forged it out, went straight to quenching it in water without any normalization, and it "spider web" cracked all across my piece. I chucked it up in the vice and gave it a whack with the hammer, breaking it in half. The grains looked very large, exactly like your piece there. I shortly found out afterwards that not all steels like a water quench and there are many more factors involved in heat treatment. Very interesting to learn how great of a difference it makes to treat your steel properly. Thanks for taking the time to demonstrate this.

[@batcountryforge5945]

The best way to learn is exactly as you did, Give it a go and test your results ;)

[@philyorkknives6651]

Great video. Keep them coming.

[@shayanthis]

A really informative video. I'm getting my workshop ready to start blacksmithing again and I was actually looking at O1 stock from Gameco last night. I'll give it a miss for now, based on this. Thanks for showing that the cycling can be done in the gas forge though.

[@londiniumarmoury7037]

Nice video, I just started working with 01 this year, I got some practice in soaking for around 8+ mins using 1095, but I have to do it by hand and eye control, as my forge isn't temp controlled, that's the tricky part, soaking by eye took me about 2 years to get down without over heating it. I had to make a very specific open back forge, which lets a lot of the heat out, so it doesn't get too hot in there.

[@shepardsforgeh2031]

Bout to make some drifts punches and chisles from o1 so thank you for this vid!!

[@itypeaname6835]

Really interesting, thank you. Subscribed. Good to hear a blacksmithing video with the right accent, too! Your voice is quite hard to hear in some parts of the video though, especially at the beginning, but the hammer strikes when you were forging were quite loud. Maybe you could (heh) normalise the volume a bit? Oh man, how did I wind up making heat treatment puns...

[@batcountryforge5945]

IType AName haha pun gold! Yeah the shotgun mic cant handle the hammer and anvil. Thanks mate!

[@MountainFisher]

Oh my goodness! I'm an engineer and heat treater. I make knives too. As far as O1 heat treat is concerned you do not hold it at hardening temp for 30 minutes nor 5 minutes. If you buy spheroid O1 with 0.10 to 0.20% vanadium like I do there is no need for for grain refinement with this steel, it is not 1080. I started heat treating O1 in a charcoal forge in 1992 and then I bought a nice Paragon oven and made perfectly heat treated knives thanks to Kevin Cashen. Firstly O1 doesn't decarburize nearly as much as 1080-75 or L6 or simple alloys. If you're going to forge it that's a different story. But it isn't necessary to do three cycles if you just buy the O1 with Vanadium and stay away from Latrobe's formulation. Some folks are under the impression that that small amount of vanadium would make vanadium carbides. Not at all, it restricts grain growth quite a bit. It is why I'd buy 80CrV2 instead of plain 1080. If you want the edge holding of a high vanadium steel and only have a forge there is a steel for you called CruForgeV that is essentially 80CrV2, but with 0.75% vanadium. Oh and FYI, vanadium carbides are harder than tungsten carbides. Alpha Knife Supply sells it in .250 thick flat bar. Do not forge below 980c to 1065c and normalize at 870 C and slow cool to room temp. To anneal heat to 760 C and slow cool at no more than 22c per hour until after it drops below 640c then it isn't as critical on the temp drop, but nothing quick, just a slow air cool after it hits 1000 F. This is Bohler's formulation. Latrobe doesn't have the vanadium. O1's analysis. Carbon, 0.95 Chromium, 0.55% Manganese, 1.10% this is very, very high for a knife steel, but has its uses. Silicon, 0.30% Tungsten, 0.55% Vanadium, 0.20% To austenitize with an oven, heat to 1200 (650c) and equalize then ramp up to O1's sweet spot at 1475 (801c) for 15-25 minutes (according to thickness) then quench in 120 to 130F oil, Canola oil or peanut oil both work, but they break down after a while. Within two to three minutes after quench if there is any warp have a vise and heavy pliers handy to straighten, but after four minutes it loses its flexibility and you must straighten during temper. This is that high manganese content, O1 is the only steel I know that will do this. Note the 15+ minute time is for O1 with vanadium only, otherwise only hold 7-15 minutes depending on thickness. The 15 minute time will put the chrome and tungsten into solution and you will get chromium and tungsten carbides. If HT in a forge for 5 min you will get mostly ferrite or iron carbides. If Liquid Nitrogen is available then use it as it will work on O1 and improve the toughness, although it isn't worth paying for the improvement you'll get. If HT in an oven for max hardness then the As Quenched hardness will be HRC 64-65. Temper at HRC 400f/204c for 2 hrs. 2x for 63-62 450f/232c for 2 hrs. 2x for 61/60. 500f/260c for 2 hrs. 2x for 59/60.

[@batcountryforge5945]

Cheers man good info!

[@lindboknifeandtool]

Would I be able to forge a piece of CPM 10v without messing anything up? I faintly remember the forging window being 1700f - 2000f. Could this be done safely without a temp controlled oven? What should I look out for? 17%~ carbide will be hard to move, so I may eventually try forging other lower carbide tool steel. Also, are high speed steels unable to be forged, or are they just harder? Thanks.

[@MountainFisher]

@@lindboknifeandtool I would stick to 52100 and not try to forge high alloy steels. I know an experienced forger and he tried forging D2 with all its Chromium and 1.5% carbon and he said it was a disaster. He made some knives, but threw them away when one just popped off the table all cracked.

[@saschaoswald480]

Wow, some amazing info right here. Sounds like Mountain Fisher knows his/her stuff. Been struggling all week with heat treating several hundred small, quarter sized parts made from O1 and arrived at similar conclusions....

[@timjackson5555]

I just cracked a 12 1/2" or 31.75 cm blade, saw it after got blade about 90 profile ground. Full integral handle think it might have happened in attempting to straighten the spine. oh well, 6 hrs on the power hammer & about 10 with the hand hammer. Just started with this stuff. was a 1" inch bar. did two blades both were roughly 16 1/2" long & 3 1/2 inched wide or 41.91 cm x 8.89 cm

[@batcountryforge5945]

tim jackson thats unfortunate Tim, what sort of power hammer was it?

[@timjackson5555]

?? not certain really. do not see a name on it. get to use my mentors every week, so not certain of the make. believe it is just shy of 100 lb ram though

[@StackhouseKnives]

Great video very informative, I wanna do a vid like this, 01 is such an overlooked steel, you can get amazing results from it :)