Heat Treat Question

Jellis11

Well-Known Member
Hey guys, I have a new question...I am using a two-brick propane forge for heat treating and Canola oil for my quench. I would prefer to be a bit more "high speed" but this is what I have to work with at the present time. So, my first few knives were successfully heat treated with this method, but my finished product has black baked in scale all over it. I essentially heat treat (01 tool steel) to just past non-magnetic, then immediately dunk it in the canola oil and hold it there until the smoke clears....then temper at 400 deg for two hours...is this process right? Should I be cleaning the blade after heat treat and before tempering? Would an anti-scale compound work in my setup? I can and have been sanding the mess off, but would love to hear of a different way. By the way, I am just a few days away from having my new (old) Wilkin Square wheel up and running. Keep in mind, I am extremely new to this hobby and still getting my feet wet.

Thanks for any help you can offer!
 
If that's the method you have to work with, I'd ditch the O1 steel and use 1080/1084 instead. It's much more suited to your heat treating methods than O1 is. O1 really needs a good soak at a controlled temperature to make the most out of it. I'm guessing you're leaving an awful lot of performance still on the table.

You can try anti scale but with simpler steels and minimal soak, it's not a big deal to grind through the scale down to clean steel anyway. You should be leaving your edges a little on the thick side anyway, anticipating having to do some clean up/finish grinding post heat treat.

I wouldn't be too concerned with cleaning the blade off between tempers. I'd also do at least two tempers at two hours each, personally.
 
I've personally never worked with 01, but from reading, and Kevin's site (best around) 01 should be soaked for 10 to 30 minutes to get best results; http://cashenblades.com/steel/o1.html

Not to hi-jack thread, but this is in line: when using a simple forge as mentioned above, while 01 will give a somewhat decent blade HT'd in simple forge, would a 1080/84 blade that's HT'd in this simple forge tend to be a better blade due to the ease of HT'ing 1080/84 steel?

edit: John, we must have been typing at same time, with your post, my post isn't needed, seems you covered everything I said and then some.

Ken H>
 
Last edited:
J. I'd ditch the O1 steel and use 1080/1084 instead. How about 1095? You should be leaving your edges a little on the thick side anyway said:
Any separation or cool down between the two cycles? Are you saying that I should clean the blade between the two tempers? Grind clean?
 
Last edited:
I cant really get a good soak with my two-brick forge....not that I know how anyway....its either hot or hotter.
 
I cant really get a good soak with my two-brick forge....not that I know how anyway....its either hot or hotter.

That's why John suggested ditching the 01 in favor of 1080/1084 because of the problem with soaking.
Between the two temper sessions allow to cool to room temp, dunk in water to speed cooling if desired. No need to clean between tempers, should not be any scale from tempering, just from heating in forge. If you use anti-scale (boax, roach powder, or a real anti-scale) you won't get much scale even in forge as long as you're not soaking.

Ken H>
 
"O1 is one of the most commonly available tool steels and has been an industry standard for many decades. It possesses a high dimensional stability during heat treatment and is not particularly vulnerable to decarburization. O1 is a fairly deep hardening steel when quenched in oil and it is for this reason that it has too often been incorrectly recommended as a good beginner steel for knifemakers. While it will harden very easily, it is a richer alloy that requires more involved heating and soak times to unlock its full potential in the hardening operation. O1 can cost as much as three times the price as a simple high carbon blade steel which can easily reach their full potential in heat treatment with the simpler equipment most bladesmiths possess, thus making it the less economically prudent choice for many bladesmiths. If you have only a forge to heat treat with why pay extra for a steel that you may not get 100% out of? If however you have the equipment to soak at precise temperature for extended periods, O1 will most likely outperform any of the simpler steels in cutting applications. "
Kevin Cashen
-----------------------------------------------------------------------------------------------------------------------------------------------
I made my first knife(s) 15 yrs ago out of O1...I could not control quality and got discouraged and gave up.for about 13 yrs. I now have a paragon furnace and am having good results with O1. I wish back then I has someone to steer me away from O1 till I had a furnace.
 
Last edited:
Thanks, so the 1080/1084 doesn't get the scale like the 01? Difference in heat requirements? "Heat to just past non-magnetic, then quench"?

Would 1095 work? I actually have a bar of that arriving today.
 
1095 might be a tad better than 01, but it's still a bit more tricky to HT than a simple alloy (1080/84).

Yes, 1080/84 will get scale build up, but since it's heated for only a couple of minutes at temp, it gets MUCH less scale than it would if held at temp for 10 to 20 minutes as required by 01. The use of an anti-scale coating really helps prevent scale build up. There are some nice anti-scale you can purchase ATP from Brownells (https://goo.gl/6sUODk) for instance. I've never used it, just always use borax (roach powder) that works very good. Just sprinkle powder on blade as you heat it some to allow white powder to melt and form a glass like coating over blade. Cheap and works good - ATP might work better, never used it.

Ken H>
 
All the steel is going to get scale to some extent. Make sure to scrub the oil off your blade with hot soapy water to make sure that your not baking on an oil residue along with the scale and then you can remove most of the scale by soaking it in white vinegar overnight and then scrubbing with a brush or steel wool.

Doug
 
1095 may not need as long of a soak as O1 but it requires REALLY good heat control and temperature monitoring or you're going to have other issues with putting excess carbon in solution.

I'd stick with something with around .8% carbon or less for your setup. That's why I recommended 1080/1084. It doesn't need too much in the way of soaking and you can't put too much carbon into solution. It's less finicky on temperatures too and with a little practice can be heat treated quite well with judging colors by eye and/or a magnet.

I agree with Ken about the tempering. I wouldn't clean the blade up between tempers, cooling with cold water in between. And for simpler carbon steels with short soaks, I personally wouldn't mess around with anti scale either as you're going to grind it thinner post heat treat anyway and that will easily remove all the scale.
 
and then you can remove most of the scale by soaking it in white vinegar overnight and then scrubbing with a brush or steel wool.

Doug

So, Is this before or after the tempering cycles? Would it work on a scaled up blade that has already been tempered?
 
So, Is this before or after the tempering cycles? Would it work on a scaled up blade that has already been tempered?

If if don't try to do a long soak time when heat treating you can skip this step. It is after tempering. You are going to get decarb and scale with carbon steels. Once you are comfortable with your grinder it only takes a minute or two to clean it up.
 
Jantz doesn't​ carry 1084. Try USA knife maker or Aldo. If you can't find 1084 try 1080, 1075, or 80crv2. I will admit that I have not tried the last listed steel but have heard good things. 1075 can be a little bit more labor intensive to heat treat out of the forge but with some practice it is a good steel. 1095 is a waste of time heat treating with forge in my opinion. I wasted a whole stick to find out that the hard way. Test, test, test.
 
Thanks Ty, yeah USA Knifemaker is out of stock on 1084 and 1080. Its cool though....I'll put myself on the waiting list......I have a half dozen blades cut out of 01 already to keep me busy for a little while. Too bad, I just got a stick of 1095 in the mail today to try. Why did you think the 1095 was a waste of time?
 
1084, and 1075 out preformed it with less work. I never could get the 1095 to harden and hold an edge without chipping.
 
Okay, good info. I guess I can use the stick of 1095 I got today to practice my grinding. (Just picked up an old Wilton Square Wheel, but working on modifying the platen before I break it in)
 
You could use to practice your heat treating. Make a test knife and beat the day lights out of it. It is a lot of fun. I do more testing then knife making. I hope that someday​ it will pay off with a quality knife that people will want.
 
Back
Top