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JohnCenter

So How Do I HT O1? (ie. the beginners steel that beginners shouldn't use)

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So as I mentioned in another post, I can buy O1 locally at a decent price (50% cheaper than my 10XX options!). I thought this was a great find until I read the comments warning me against using it due to the difficulty heat treating it. But... I've also watched and read numerous articles on how it is a great steel for beginners and can be easily heat treated. Here are two links I believe to be  respectable examples of that opinion: "Gough Custom" (https://www.youtube.com/watch?v=8bunCG6W6dA) and this "Popular Woodworking" Article Summary (https://www.popularwoodworking.com/woodworking-blogs/editors-blog/heat-treating-o1-steel) I have found cited way too often.

Yet on many of the knifemaking forums (like here), it is often touted that O1's heat treatment ease is a misconception. Therefore, I ask two questions to hopefully better understand O1 and it's reputation:

(1) Why does O1 have this contrary reputation?

(2a) Can it be adequately heat treated using simple means/ forges?

(2b) If yes, which of the many 'simple' forges (two brick, coffee can, etc.) is the more reliable option?

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The secret is in your words. "Adequate". 

A lot of things can be "adequate" but, for most, that is not a very high bar or goal. Most bladesmiths strive to "optimize" the steel they choose and to get the best performance from it that they can.

To put it simply, a steel that requires a complex heat treat for optimal performance may well harden somewhat, be somewhat tough, take something of an edge, if HT'ed "simply". It may even outperform some steels that have been optimized but it is a pretty good bet that there are other steels that, optimize under simple methods that will outperform it. Some steels aren't much at all if they aren't optimized. 

I don't know anyone who would be satisfied looking at a finished knife, with all the work put in to it, and having to say "it could have been so much better if I could have heat treated it better." 

O1 doesn't make a terrible knife when simply treated but for me I'd look at the knife like looking at a paint job I did without prepping the surface properly. I may have used the best paint and it may last a long time but I will still feel bad about it judt being an adequate job.

If you are going to stock remove O1 and doing an "adequate" HT with a basic small forge then a two-brick or a coffee can will be equally reliable provided they are made and used well. The problem with the small forges, powered by the handyman 1# torches, provided the blade is't too big for the forge, is being able to observe decalescence when it occurs, which is a key to a basic HT.

 

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To elaborate a bit, simply heating to decalescence and quenching O-1 will give you a hardened blade, roughly equal to 1084 in edge holding and abrasion resistance.  Following the proper procedure of soaking at heat, however, allows the carbide-forming elements to come into solution and distribute themselves evenly.  This structure when quenched and tempered results in a blade that can shave slivers off the first one with no damage.

So, while a simple heat treat sort of works and will produce a decent blade, that steel is capable of much higher performance.  A better comparison would be driving a supercharger-equipped car with the supercharger turned off.  It will still get you there, but not as well as it has the potential to do.

That's why some of us get snobby about it.  We're steel geeks.  ;)

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Would the addition of a thermocoupler make a difference when using a simple forge type design?

This way a better approximation of correct temperatures can be had.

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19 minutes ago, JohnCenter said:

Would the addition of a thermocoupler make a difference when using a simple forge type design?

This way a better approximation of correct temperatures can be had.

IMO its a helpful tool. I thought it was gonna make my HT  so easy a monkey could do it....it didn't /doesnt.

I still use a magnet and watch for decalescence..... but at least I know if my muffle is 1400 or 2000*

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Given the soak times and the humanoid interface between a thermocouple display and the fuel supply/heat control on a simple forge IMHO it is going to be difficult to usefully hold the neccessary temperatures. I wish it would work. I'd love to have that kind of heat and time control in a unit the size of a coffee can or jumbo box of Kleenex, and to have it cheaply as well.

 

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I have been wondering what happens to the carbon that is not dissolved and doesnt contribute to hardening.

If you have .84% of a blades carbon hardening a 1% carbon blade do you have .84% of the max hardness or 99.16% of the max hardness from that blade? 

If there is left over carbon what does it do? Does the extra carbon just stay in the grain boundries with no effect?

Because o1 would have extra carbon with a simple heat treatment, does that mean 1084 will preform better because it is all hard with no waste in the steel?

If 1084 preforms better than o1 with a simple heat treat then 01 is making a bad blade, but if they both preform as you would expect a simple heat treat would then you arent losing anything.

So from the simple heat treatment on o1 steel, do you get what you would expect from 1084 or are you going to get less than the highest possible results from 1084 because there is extra stuff in the blade?

 

While using my knives made from mystery steels of all types, I have noticed when a steel did not have quite enough carbon but I havent noticed the opposite. 

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O1 also has chromium, vanadium and silicon amounts similar to 80CrV2. The vanadium will help keeping the grain small, the chromium increases hardenability and toughness while the silicon adds impact and abrasion resistance. I am not entirely convinced a simply heat treated O1 would perform as 1084. Perhaps rather like a simply HTed 80CrV2. Jerrod? Where are you? :lol:

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2 hours ago, JohnCenter said:

Would the addition of a thermocoupler make a difference when using a simple forge type design?

This way a better approximation of correct temperatures can be had.

It will help.  Not going to make it fool proof but it will certainly help.  Make sure to get the high temperature K type probe TC.  Don't skimp on the thermocouple and it will last and give you good results.

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18 hours ago, Joël Mercier said:

Jerrod? Where are you? :lol:

Just got back from the 122nd American Foundry Society Metalcasting Congress in Ft. Worth, TX.  Very educational event.  

But I don't see where I'm needed here.  Let's face it, there is enough great knowledge and knowledgeable people on the forum that I doubt I'm ever really needed here, and this thread is a great example of that.  You guys covered it pretty well.  

It may help to keep in mind that the excess carbon that isn't being driven into the lattice to form martensite is either going to be tied up in a carbide (iron, chromium, vanadium, or other) or stay dissolved in the FCC matrix giving you retained austenite.  The extended soak on alloys like O1 and O2 is to dissolve the carbides and get as much carbon into play as possible for forming martensite.  This often produces retained austenite, that gets converted to martensite during tempering when enough energy (heat) is added to let carbide reform (thus reducing the C dissolved in the retained austenite).  If you do your normalizing cycles right, you can get grain and carbide refinement pretty well before final heat and quench.  If you already have fine carbide distribution prior to quench, you don't really need to soak for too long, because most of what you are trying to achieve is already done.  Also, your finer carbides dissolve faster than bigger ones, so you more readily get the spare C into solution.  

Let's not forget that 1084 makes a great knife.  If you don't achieve optimal results with O1 or O2 and end up with something "only as good as 1084", you still have a great blade (everything else being equal).  Anything you can do to improve on that is fantastic, but if you don't reach perfection: Don't worry!  You're still doing great.  

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O-1 is a fine steel to use. Even for a beginner. All the hubbub and snobbery is hogwash. Use it. Heat treat it and learn how to make it be what it can be. The truth be told getting "optimal" results from O-1 rather than "nominal" results is nothing to be afraid of.

On ‎4‎/‎6‎/‎2018 at 11:03 AM, Jerrod Miller said:

If you do your normalizing cycles right, you can get grain and carbide refinement pretty well before final heat and quench.  If you already have fine carbide distribution prior to quench, you don't really need to soak for too long, because most of what you are trying to achieve is already done.  Also, your finer carbides dissolve faster than bigger ones, so you more readily get the spare C into solution.  

This pretty well sums it up.

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15 hours ago, Joshua States said:

O-1 is a fine steel to use. Even for a beginner. All the hubbub and snobbery is hogwash.

I will second this. It is a meme that I believe originated on Kevin Cashen's site, and is repeated continually, often almost verbatim across the internet.

Give a novice 1080 and it is very possible or even likely that they will produce a knife with enlarged grain structure. I've seen that many times. It can also be prone to warping.

O1, on the other hand, is ubiquitous for a reason, and except through utterly egregious mishandling it is very easy to produce a hard knife with fine grain that is relatively stable in the quench. It is the Ron Jeremy of steels.

 

 

Edited by Dan P.
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So is 80CrV2 :lol: but of course, if he can get O1 for cheaper than 1080 or 80CrV2, it's a no brainer.

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47 minutes ago, Dan P. said:

I will second this. It is a meme that I believe originated on Kevin Cashen's site, and is repeated continually, often almost verbatim across the internet.

Give a novice 1080 and it is very possible or even likely that they will produce a knife with enlarged grain structure. I've seen that many times. It can also be prone to warping.

O1, on the other hand, is ubiquitous for a reason, and except through utterly egregious mishandling it is very easy to produce a hard knife with fine grain that is relatively stable in the quench. It is the Ron Jeremy of steels.

 

 

Even Kevin Cashen has admitted that the soak times and/or the extra steps in the normalizing process, basically results in the difference in as-quenched hardness of 65 HRC rather than 62 HRC. So I ask you: How much difference does that make when you are going to temper this down to 375*-400* and wind up with 60HRC?

I'll tell you what the difference is. Starting at the higher hardness means that more of the available carbon has been freed from being locked in those carbides and is more evenly distributed in the blade. This increases the edge holding capacity, which in turn is considered part of the blade "performance level". A simple way to do this is to normalize well above non-magnetic (1600*+ for those of you with thermocouplers or ovens, bright orange for those of you who use colors) and let it air cool to magnetic again. Then, if you so desire, another normalization around critical (1475*) and let it cool to magnetic again. Quench out of 1475* into a medium speed oil and that O-1 will be rocking the Kasbar.

22 minutes ago, Joël Mercier said:

if he can get O1 for cheaper than 1080 or 80CrV2, it's a no brainer.

Exactly. You can buy a 36 inch long 1 inch diameter O-1 drill rod from MSC direct for about $12/foot. It only takes 3-5 inches to make a knife. (5 inches will make a Bowie that is 8" blade by 2" wide by 1/4" thick) Do the math.

Edited by Joshua States

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I don't recall anyone saying that a simply heat treated 01 blade would be "terrible". It will be, all things done right, a "good" blade it just won't come near its potential. I ran into this years ago with another steel. I was very impressed, and still am, with 52100. A certain maker was sounding the trumpet for the steel and I jumped on the bandwagon just based on the, shall we say, public persona of the steel. Using basic equipment and with a bit of heat treating knowledge I thought that even though I couldn't really optimize the steel it must still make a much better knife than a 10xx series simply because it had the potential. It was, after all, a "better" steel (potentially) so therefore it must always make a better knife.

To make it simple, I wish I had that steel back and that I had used a simple 10xx steel for the knives I made with that 52100.  I would have ended up having more pride in getting the best out of, say, 1080, 1084, 1080+ ( as 80CrV2 was called then) than I had when I realized that I had gotten "really good" 1080 level performance out of a steel capable of much more.

If someone has a supply of 01 or it's readily available it will make very good knives simply treated, nobody is denying that, but you can't really "brag", "tout" or hang you hat on the steel you used without having to be honest to yourself or the buyer/recipient and admitting you didn't get the best out of it. I can't tell anyone that the 52100 blades I made were "great" because of the steel I used. They were simply "OK" . I didn't make anything special out of the steel.

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I admit I drank Kevin's Koolade, he's just such a nice and enthusiastic guy in person with great micrographs to show.  As I've said before, I'm a steel nerd. :lol:

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We learned in the bug wars on klandathu if a blade isnt utterly sharp that a thrust would just glance off the hard exoskeleton of an arachnid beast and you might not get another chance at it, or maybe those were roaches at my friends place...

Either way I dont know why we were fighting them like that, we should have just bounced out of there and gassed them from the sidewalk.

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1 hour ago, Vern Wimmer said:

I realized that I had gotten "really good" 1080 level performance out of a steel capable of much more.

 

I'd love to read the peer reviewed studies on the difference in performance between optimally HT'd 1080 and 52100 in the application for which you used them.

Or are your statements perhaps more opinion based?

 

 

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23 minutes ago, Alan Longmire said:

I admit I drank Kevin's Koolade, he's just such a nice and enthusiastic guy in person with great micrographs to show.  As I've said before, I'm a steel nerd. :lol:

Nobody's doubting the science, but speaking for myself I would rather have science and opinion presented at a respectable distance from one another.

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9 minutes ago, Dan P. said:

I'd love to read the peer reviewed studies on the difference in performance between optimally HT'd 1080 and 52100 in the application for which you used them.

Or are your statements perhaps more opinion based?

 

 

The point there was not about both being optimized but having the ability to optimize simple 1080 but not 52100. Treating the 52100 like 1080 did not provide spectacularly improved performance over the 1080 despite the fact that, had the 52100 been brought to its optimal level, there most likely would have been. Of course OPTIMIZED 52100 will have significant benefits over OPTIMIZED 1080 but I never said it didn't.

 A POTENTIALLY "great" steel does not automatically convey its atributes to a blade unless it is treated to its potential. It might have more "toughness" due to its alloy, OTOH it might just be harder to sharpen the .84% of carbon that went into solution because of the alloy. 

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2 hours ago, Joshua States said:

36 inch long 1 inch diameter O-1 drill rod from MSC direct for about $12/foot. It only takes 3-5 inches to make a knife. (5 inches will make a Bowie that is 8" blade by 2" wide by 1/4" thick) Do the math.

I actually did that math a little while back I bought W1 rods for dirt cheap at Acklands. I had a big surprise when I tried to move the steel from round to flat :lol:. Definitely not for the newbie. Well, thinking about it, it did teach me a few things including the limits of my arm. O1 work hardens a bit, it must be even worse. A shop press would be welcomed.

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Forge it hot man! O-1 likes to be forged around 1600- 1900 degrees. Every steel moves easier when it's yellow.

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O-1 was the only steel I had access to in the late 80's when I first started in the craft. It is far more forgiving than the reputation it has earned.  Believe me, I played pretty fast and loose with that steel (as only a 17 year old with a farrier's forge can) and I still have knives I made from that time that work quite well. It even makes a decent pattern weld when paired with simple mild steel (not a great contrast, but it works).  I wouldn't recommend making a longsword out of it, but it's a great steel for knives, and as Alan said, if really HT'ed well it can be pretty impressive.

Alan, Jerrod, and the other steel geeks are to be heeded if you want precision and optimal performance (I follow their advice), but my point is that you don't need to be too paranoid with this steel. It isn't a crystal goblet. It's pretty forgiving despite its reputation to the contrary. 

Luck!

 

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I'm sort of embarrassed to admit it, but Jerrod's mention of the forging and normalizing heats doing the work of a long soak is something I totally forgot.  -_-

I was totally focused on stock removal and HT from a spheroidized annealed condition.  

I do use O-1 to make die-sinker's chisels for doing silver inlay into steel.  Using a muffle in the coal forge works very well for those.  They ended up both tougher (as in hold an edge longer) and less chippy than my M42 HSS ones.  

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