80CrV2 and wood charcoal...what was I thinking?

S

soundmind

KNIFE MAKER
You all have been very gracious with me. I know I haven't gotten out a fully handmade blade yet. I've accepted opportunities to fix handles and things like that that have gotten in the way of what I really want to do. But I feel close - but just feel like I hit another wall. Maybe it's not as big a deal as I think. Anyway, I was wondering If I could bounce my thoughts off of you all?

First, I don't think wood charcoal gives even heat - even with air on it and firebrick insulating the top - but it looks very close, though.

But....Second, I think the coals touching the thermocouple are different than the temperature of the steel. I had a reading of 1475-85 but the steel still attracted a magnet.

Third, since I can't be for sure of the temperature, or consistently hold it, I can't reliably experiment with soaking this steel.

Fourth, I'm using a lot of wood and time to keep constant heat and trying to soak. I'd say two 1/2 day sessions with only six test strips and two blades hardened and snapped. So this way is definitely not efficient.

Not sure if very many people use or have used wood before (that may be an indication for me not to), but if someone has and can say it's worth figuring out, then I'll keep trying. I have good seasoned wood that's making nice charcoals and have some ideas from bladeforums for making a baffle for an even heat chamber.

But is this just an uphill battle I'm not going to win? I wonder what you all think if its better to cut my losses and either wait until I can get gas again, sending my 80CrV2 out for heat treat, and/or using a different steel if all I have is wood as a heat source. All of that is about a two week time frame and I can afford one of those options, not all three.

Anyways thanks all.
 
I have seen people hardin 1084 with a camp fire and a shop vac. It is not easy though. I have also seen people heat treat 1084 with a 1 brick forge and plumbers torch. I think 80crv2 is a little harder to heat treat with simple methods. To get the most out of 80crv2 you really want a temp and time controlled method to "Heat treat" it. I'd say send the 80crv2 out to heat treater and get some 1084 for the charcoal heat treating. This is just my opinion so take it with a grain of salt. There are plenty of people that will tell you that 80crv2 is so easy to hardin that they can hardin perfectly by just staring at it.
PS: that last part was a Joke
 
Yeah I was going to start using 80crv2 for all of my knives but because I use "backyard heat treating methods" I was advised by Storm crow to go with 5160 and triple normalize triple quench and triple temper and that's exactly what I did. It's alot more work but I like the results so far. I need to do some of my own testing
 
I think I mistook 80CrV2 for a simple steel b/c it was said to be similar to 5160. I was about to make an order for 5160 when I learned about this steel and thought I was getting a better deal for the same price, so to speak - a tougher steel but still easy to learn.
 
Like Kevin said use 1084 if you cannot get that then 1080, 1095 or 1075. Second to that I would suggest looking over your forge design. Maybe post some pictures of your forge especially your Tuyere area. I have forged with lump charcoal many times but have not used a thermocouple so I may not be able to help there. Also, do not be concerned about not producing a "fully hand made blade" its not a condition of membership here we want to help you succeed. We all started somewhere.
 
I've use charcoal and it is a pain in the back side at times. You can spend more time tending the fire than forging. As far as not being able to get enough heat from a charcoal forge, properly constructed and tended, a charcoal forge should be able to burn steel. You will need about six inches of fuel under the work, that was my main problem with some of my first forges, and about two inches of fuel over your work.

Second, don't go with a soak time at a given heat with any solid or gas fueled forge except for no more than a couple of minutes and even that can be tricky and can cause grain growth. A thermocouple with a pyrometer is of limited value in a solid or gas forge, in my opinion. It is much better to check on decalesence in a forge and save the thermocouple and pyrometer for a regulated oven.

I have not used 80CrV2 so I'm not going to expound on it's virtues or lack thereof. I will say taking look over the offering out there that most of the 1080 and 1084 aren't really 1080 or 1084. They both seem to have low levels of other alloying metals in them so you might order 1080 and find out what is shipped to you is pretty much 80CrV2.

Doug
 
I've been collecting info on 5160, 1084, 9260, and 1095 (but I don't see me holding 1095 at temp). I'll look up HT info for 1075 and 1080.

I was working in a 2/3 barrel woodstove (outside). The coals looked good and I wanted to control draft with the damper.

A proper coal forge isn't too far out of reach for me. But gas is also an option for me again. It's good to know it would be difficult to hold temperature with gas, too. (I kind of noticed that already, with the temp actually climbing when I turn down the gas.)

That's interesting about the similarty between the steels, Doug.
 
It matters though how deep your coals were and where you had your steel placed in that fire, bottom blast side blast etc. However I think if I were you I would get some 10-series and try a simple HT with proper temper cycles and I think you will be happy with your results. It really does not matter how you get a simple steel to non-magnetic as long as it gets there and is quenched properly it will harden. It may not harden all the way to "RC whatever" but it will harden to the point where you need to draw it back some. In either case I would change one variable at a time otherwise you will not know what has worked.
 
Sound Mind Kevin Cashen has a dvd for sale for heat treat 1080/1084. He explains how to do it in a simple forge and he also explains how to do it in a heat treat oven. I have it and it is worth every penny. I think you can get it from his website. Just google Kevin Cashen and you will find it
 
I think you're right Chris: heat is heat. I think that applies to what Kevin said that charcoal "done right" puts out "a very hot even flame that is clean". And I think that's why I wanted to give it a shot. My last two test strips I ignored the thermocouple and used a magnet without removing the steel, then let it climb a little higher and quenched. (This was with thermal cycles).

I found online ways to baffle the heat. And with more fiddling around I might get ballpark, especially with what I know now from you and Doug that you need a good base of coals. My base was about 3-4 inches. But I think I would still be left with a questionable HT without a lot of personal experience to interpret what I was doing.

Yeah Jason, I do want to get Kevin's videos sometime.
 
I wouldn't necessarily say you can't get a good heat treatment out of 80CrV2 with an eyeball heat treatment, but it is going to be harder to be consistent, and you won't be getting the most out of the steel without being able to soak at a set temperature. I eyeball heat treated for years, mostly with 5160 and 1084, and had quite happy customers. If you are going to be heat treating the way you describe, I would swap alloys to either of those. If the only steel available to me to make knives from for the rest of my life was 5160, I would be quite happy.

For a charcoal forge, coal forge, or gas forge, I find that a "muffle furnace" makes heat treatment much easier. Essentially, you heat a piece of UNGALVANIZED steel pipe so that it is evenly hot inside, then heat the blade inside the pipe while the pipe is still in the forge. If you cap one end of the pipe and put some charcoal, twigs, wood shavings, or other carbon-bearing material inside, it will burn and create a low-oxygen atmosphere inside, reducing the amount of scaling. The muffle furnace prevents over-heating, and allows for more even heating of the blade. This is a trick I learned years ago from Tai Goo.

I would suit the alloy to the task at hand and the heat treatment methods available. You can cover a large portion of cutlery needs with 5160 and 1084. There are plenty of knifemakers who farm out the heat treatment to professionals, but you have to keep an eye on the results from them, too, as mistakes are made sometimes. A heat treatment furnace is a decent chunk of change, but it certainly makes life easier, and if you are selling knives will pay for itself quickly.

Kevin Cashen is a tremendous resource. Make use of his website and video.
 
Justin W. said:
Yeah I was going to start using 80crv2 for all of my knives but because I use "backyard heat treating methods" I was advised by Storm crow to go with 5160 and triple normalize triple quench and triple temper and that's exactly what I did. It's alot more work but I like the results so far. I need to do some of my own testing
Click to expand...

With the addition of a digital furnace some years ago, I have swapped to a single quench and have had good results. Being able to set a specific temperature makes life easier. Three normalization cycles and three 1 hour or two 2 hour temper cycles are not going away, though. :)
 
Stormcrow said:
I wouldn't necessarily say you can't get a good heat treatment out of 80CrV2 with an eyeball heat treatment, but it is going to be harder to be consistent, and you won't be getting the most out of the steel without being able to soak at a set temperature. I eyeball heat treated for years, mostly with 5160 and 1084, and had quite happy customers. If you are going to be heat treating the way you describe, I would swap alloys to either of those. If the only steel available to me to make knives from for the rest of my life was 5160, I would be quite happy.
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That sounds really good. Especially the last line about 5160 being good if that was all that was available.

I also noticed once the thermocouple wasn't giving me the right temp, I did have to default to eyeball. And if that's the case I can't even guarantee my thermal cycles.

Maybe a few knives of 5160 done correctly will get me a digital furnace. I do want to use 80CrV2. It seems like I'd get a knife that can be ground thin, hold a good edge, and its okay if you use it wrong sometimes.:)
 
Stormcrow said:
With the addition of a digital furnace some years ago, I have swapped to a single quench and have had good results. Being able to set a specific temperature makes life easier. Three normalization cycles and three 1 hour or two 2 hour temper cycles are not going away, though. :)
Click to expand...

Hey thanks for explaining that so much better so I didn't have to lol. I did that whole process and have been carrying around the knife and using the crap out of it. It preformed great and I can't wait to make more
 
I've worked with 5160 and 9260 and they're great alloys, especially for larger blades that need extra toughness. The one problem with 9260 is trying to find it. Admiral Steel used to sell it but stopped a few years ago. The good thing about them is that you can heat them enough to put 100% of the carbon into solution and you won't have to worry about retained austenite because the carbon will be well short of the saturation level. Steels like 1095 can be supersaturated and cause problems with retained austenite which you have to deal with later. Some say that the cut offs of steel from suspension shops is 9260 but don't count on it unless they say that it is and there's a good chance that they won't know.

I would also recommend that you don't go by heating to non-magnetic. That happens at a slightly lower temperature than phase change which is needed to harden a blade. I strongly recommend that you learn to go by decalesence until such time as you can afford a regulated heat treating oven (there's never such a thing as too much temperature control). Decalesence shows that the iron crystals in the steel are actually changing phases. Down side is that you might end up having to do your heat treating in the dark of night to see it more easily. You should be able to find videos of decalesence on YouTube.

I would not do triple quenching, even on the lower carbon steels. Yes, there is the theory that the repeated quenches will help refine the grain but in practice the subsequent austenizing will undue the effects of the previous quench.

Doug

P. S. If you do find a commercial outlet for 9260 please let us know.
 
Thanks everyone. I'll rethink my steel choice.

I've got some other questions about grainsize that I should let simmer a little longer. But generally, is coarse or questionable grain due to improper soaking at thermal cycle and austenitizing temps?
 
Too much heat for too long grows grain size. There may be more factors I don't know about, but if you are properly thermal cycling, you are essentially rebooting the steel to a good starting point for hardening. So thermal cycling should not be growing your grain.
 
To heat cycle bring the blade up to where the shadow from decalesence passes and get just a bit hotter and allow to cool. Second cycle bring the blade up until the shadow from decalesence passes and immediately cool in air. Third cycle bring the blade up to red but don't allow the shadow to form on the steel and then air cool. That's about as good as you can do for heat cycling without a regulated oven.

Doug
 
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