anealing wrong?

[junker]

im trying to aneal some 01 for a knife (already forged to shape just need to grind). but no matter haw long i make it take to cool it just keeps skating my files, i even had it cool with other hot pieces in the bucket of sand and even then it just skates. this last time when i tried when i pulled it out of the bucket it had curved considerably. im trying to finish this knife for a friend of mine who will be shipping to afgahnastan soon so please help!

[Jeff Seelye]

im trying to aneal some 01 for a knife (already forged to shape just need to grind). but no matter haw long i make it take to cool it just keeps skating my files, i even had it cool with other hot pieces in the bucket of sand and even then it just skates. this last time when i tried when i pulled it out of the bucket it had curved considerably. im trying to finish this knife for a friend of mine who will be shipping to afgahnastan soon so please help!

Sounds like you didn't get it hot enough to be able to anneal it. O1 must get above 1400 degrees F to anneal. Try to stay below 1500 degrees F. Try vermiculite, the slower the better. If you have a furnace that you can control drop the temp about 50 degrees F per hour till you are below 1000 degrees F then do the hot sand thing.
Hardening is a trick to. Slowly ramp it up to 1200 deg. F then go to 1450 to 1500 for a half hour. Oil quench. 500 Deg F for 1 hour will give you a temper of about 56 R/C

[forgemaster]

We had a job to anneal some drill rod ends for a mining supply company some years ago, I figured "right take it to 850/820 deg C and let it slow cool in the furnace". Nearly sent me mad trying to get it to the correct softness, the stuff just would not anneal. Eventually the customer said "oh yeah we have a spec sheet on this material" after reading the sheet I found that this steel needed to have pretty precise heating and cooling to anneal properly, ie heat to 690 to 710 deg and allow to slow(furnace) cool. Success every time then. The lesson I learned here was where possible check the spec's beforehand.

Phil

[junker]

isn't vermiculite styrephome? wouldn't it just melt?

[bigfootnampa]

isn't vermiculite styrephome? wouldn't it just melt?

NO! Vermiculite is volcanic in origin... sort of mica popcorn. It is commonly used to anneal metals. Put it in a metal bucket. preferably one with a cover. You can get it at the garden departments of Lowe's or Home Depot and most other garden suppliers. Wood ash works pretty good too... sand not so well.

[pkrankow]

I like fluffy wood ash, I keep it in a 5 gallon lidded ash can and can anneal about 12 inches. maybe a little more. You need about 2 inches on the ends to have enough insulation.

My wood ash is free, just have to clean out the fireplace.

Phil

Oh, I looked it up.
http://en.wikipedia.org/wiki/Vermiculite

[MattBower]

O1 is a hypereutectoid steel with ~1% C, and it contains some strong carbide formers. The traditional anneal -- heat above critical and slow cool in vermiculite, etc. -- will only cause it to form big, nasty carbides. Those carbides are extremely wear resistant and will make it a ***** to machine. Many a bladesmith has learned this when trying to drill slow-annealed 1095 (another hypereutectoid steel, but without the extra alloying elements). By repeatedly slow cooling it, you've made the problem that much worse. More info here: http://www.bladeforums.com/forums/showthread.php?t=615086

So now ya gotta fix it.

What kind of heat treating equipment do you have?

[pkrankow]

Thanks Matt, that is a lot of info in that link...I'll have to reread the first page a few times to absorb most of it.

Phil

[MattBower]

Thanks Matt, that is a lot of info in that link...I'll have to reread the first page a few times to absorb most of it.

Phil

I know how you feel, Phil. The fix for this is going to be a bit of a head-spinner, too, especially if junker has nothing but a forge to work with. This is why I try to keep to simple, roughly eutectoid steels -- 1075 to 1085.

[Jeff Seelye]

Matt, that is incredible information! I spent several years working in heat treat shop with High tech equipment with all vaccuum furnaces. (I guess you could call it a furnace programing job)I never had that problem but the program must have done it. Thanks again for the great link! My old heat treat manual was where I got the temps from and It never said anything or explained it like that. My info was basically just like Stewartthesmiths. I just added 4 pages of new info to my old manual.

[junker]

wow my head is spinning from that. and all i have are basic tools (forge, hammer, files, etc) i've never really wanted to get more complicated than that. always thought making knives old school meant going REALLY old school lols.

[ThomasPowers]

Of course "old school" is not using modern alloys!

[MattBower]

after reading the sheet I found that this steel needed to have pretty precise heating and cooling to anneal properly, ie heat to 690 to 710 deg and allow to slow(furnace) cool.

That's a spheroidizing treatment, which is exactly the thing for something like O1. (Of course that's why the spec sheet recommended it!) Notice how it's all sub-critical? (710 C is about 1300 F. At that temp you don't make any austenite.) That's key. But it's probably going to be tricky without a HT oven. It should be possible to come up with something close, though.

[MattBower]

Junker,

Don't feel bad about the spinning head; I barely understand most of this stuff myself.

Here's what I suggest you do. This is based mainly on an exchange I had with a metallurgical engineer on pretty much this exact subject. (I don't claim that I would've been able to figure this out on my own.) The temperatures I'm going to mention here are mainly educated guesses. I make no warranties, etc., etc. And you're probably not going to like some of this. Sorry 'bout that.

Take your blade up to a nice, even temperature well above critical. Say, maybe 1700 F. Remove from heat and allow to air cool far into the black. (And note: "air cool" doesn't mean set it on the anvil! ) We're dissolving those big nasty carbides. Air cooling should bring the steel down from austenite fast enough to keep most of them from bunching back up where we don't want them.

Repeat that heat and air cool process again, but this time only take it up to around around 1500. We're bringing the grain size down, although those strong carbide formers in O1 will tend to retard grain growth, so the grain size may not be so bad to begin with. (If there are any grain boundary carbides left, I suppose this might also help disperse them. I'm not certain about that.)

Now harden the blade by oil quenching from ~1500. (O1 does not need a super fast oil.) As Jeff suggested, to get the best out of O1 you really should let it soak at temp for a good 15+ minutes before the quench. With just a forge, that's not easy to do without overheating. (What sort of forge do you use, by the way?) The point of this step is to make martensite, because martensite is a really good starting structure for producing very fine carbides in the next step.

The blade should be full hard and brittle at this point, so immediately go to tempering -- or in this case what a lot of folks call a sub-critical anneal. Cycle the blade up to a very low red -- approx. 1200 F -- and back to black as many times as you can stand. (If you can hold at 1200-1300 F for an hour, that's even better -- but again, that's hard to do with just a forge.) Do not let it go non-magnetic. This should to give us tiny little carbide clusters throughout the steel. The steel will machine pretty easily, and when we go to re-harden after machining, the carbides will dissolve back into solution fairly quickly.

Whew! Now you should be able to file and sand easily. When you're ready, harden again and temper to your desired hardness.

I know that all seems absurdly complicated, but AFAIK dealing with your problem is going to require something along those lines. If you skip the soaks during hardening, you'll sacrifice some edge holding but you should still get a usable blade. You really do need to get rid of any grain boundary carbides, though. Those'll tend to make your steel brittle, and you absolutely don't want to send your buddy off to war with a brittle knife.

Of course another option would be to get a piece of 1084 and start over. I know that's not what you want to hear, but it'd give you far fewer headaches in the HT department. http://www.usaknifemaker.com/1084fg-steel-bar-14-x-112-x-12-p-284.html

[junker]

that's a bit more work than i have in the knife up to this point . it might be better just to restart with a different alloy of steel. what steel is simple yet similar in hardness to the o1? and again please remember that this knife is going to afgahnastan so 1 of the biggest reasons i chose o1 was that i had read that it held a great edge yet wasn't shatter prone. what steel would give these charicteristics? and im keeping this knife kinda thick for maximum durribility so that might be a factor too.

[Rich Hale]

I do not mean to offend your abilities to learn and progress in wotever you want to do. Please step back and rethink this piece and leave it in the hands of someone that has experience and expertice. MAybe consider this as a rifle or pistol and put your self in the receiving end of the deal. Would you want to be in a war zone and depend on a firearm that was the first piece made by a new ? I would not.
In fact I do not have a military background so will only surmise that If I had to resort to an edged weapon as last resort I would want it clear in my mind that I had the best I could get my hands on.
As you have already found out the way a knife is heat treated as well as the material selected is absolutely in this case vital to the knifes capabilities.

In fact I am really glad that you chose 0-1 as it gave you a real insight as to how one kind of steel works and the pitfalls than you can step into getting it
right. It also gets this thread open for all of us to learn from and as yo have seen from the answers above there is a huge vault of knowledge on this site that shows up when problems like this come up. Obtain a knife well made from someone with a long history of well made blades. Ship that and then continue learning.

[junker]

im sorry if i made it seem like this will be a combat knife. it will not. it is a utility knife. he has an army issued k-bar style knife (except double edged) for fighting. if this knife even gets used it will only be utility (knowing him he might just hang it up on the wall to remind him of home ) im just trying to make my bud the best knife i can before i go to bootcamp too lols.

[MattBower]

I was serious about the 1084. It contains the most carbon that steel can accept without having the potential to cause the problems that you ran into with your O1. It'll get good and hard, it'll hold a good edge (not quite as good as properly hardened O1, but the key there is "properly hardened"), and it won't be prone to form grain boundary carbides. The little bit of vanadium in the stuff I linked to will also tend to slow grain growth, which is nice. Best of all, it's very simple to heat treat. The common advice to take steel a bit past non-magnetic and quench it really isn't optimal for a lot of steels. For 1084, though, it's just about right.

[junker]

where can you pick up 1084? it isn't avalaiable in any of the metal sales places around me. is there a specific place online you get it from?

[zampilot]

im trying to aneal some 01 for a knife (already forged to shape just need to grind). but no matter haw long i make it take to cool it just keeps skating my files, i even had it cool with other hot pieces in the bucket of sand and even then it just skates. this last time when i tried when i pulled it out of the bucket it had curved considerably. im trying to finish this knife for a friend of mine who will be shipping to afgahnastan soon so please help!

If the file skates, it's hardened. Do you mean to temper the blade so it'll take a sharp edge vs annealing (softening) ?

But I'm a wild-guessing newbie so I may be fit for slaughter!

[junker]

no i meant to aneal it to soften it up for filing.

[MattBower]

where can you pick up 1084? it isn't avalaiable in any of the metal sales places around me. is there a specific place online you get it from?

http://njsteelbaron.com/

http://www.usaknifemaker.com/store/1084fg-steel-bar-14-x-112-x-12-p-284.html

Admiral's 1075/1080 would be close enough: http://www.admiralsteel.com/shop/

if the file skates, it's hardened.

Please go back and read the rest of the thread. Skating a file does not prove that you have martensite.

[LLG]

Forty years ago when I worked in an industrial blacksmith shop, we had a metal box with a couple hundred pounds of slack lime in it. This was used to anneal steel. Heat the piece and bury it in the lime. Leave it overnight. In the morning it was always too hot to touch. Remove from the lime box with tongs.