Difficulty HT 1095 May be overstated...

D

David LaFerney

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Feb 4, 2015
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A little while back I watched a Youtube vid by Walter Sorrells about making your first knife in which he made several recommendations including not to use mystery steel - instead order some simple high carbon steel such as 1095 from Admiral or somewhere. So I ordered a couple of 72" pieces of 1095.

Then I started reading on here and in other places about how 1095 is a poor choice for beginners because it needs well controlled temps for hardening + a nice long heat soak at temp, but not too hot or it gets ruined, and it needs special quench oil that is more expensive than decent whiskey... Etc. Also the shops that you can send off to for HT don't like simple carbon steel.

I'm sure that all of that is true.

But I've got 12' of the stuff, and a knife ready to heat treat made out of it.

Damn.

So I decided to do an experiment. I cut of a 7" peice of 1x1/8 1095 and annealed it just for good measure. Then I heated it until a magnet wouldn't stick to it and let it cool to black twice. Then heated it back up and quenched it in used peanut oil left from the Thanksgiving turkey fry. Cross my fingers. The file says it's hard. So into the oven at 475 for an hour. Then I ground a crude edge on it - taking off a good bit of metal to make sure it isn't just hard on the outside.

Sharpened it up - Razor sharp. No kidding you could shave with it. Then I batoned it through some 2x4 that's laying around the shop. Still razor sharp.

Now I know that it's probably nowhere near as good as it could be - unless I just got really lucky - and it might break way too easy, or curl up the first time I beat it through a penny. And honestly it seems really easy to sharpen - so resistance to abrasion is probably not all that high. BUT - it's my first time, and it really seems to be a reasonably serviceable blade.
 
The difficulty in heat treating 1095 has certainly been overstated in the past, but for good reason, for sure. While peanut oil and the like will certainly harden 1095 to a good extent, they cannot harden it to a great extent, as you surmised. A file skate test may show you that you were able to make the EDGE of a canola/peanut/mineral/etc oil quenched knife harder than the file, but if you are not using a very fast quench, you are not reaching max hardness. Therefor you likely have some fine pearlite mixed in with the martensite.

Canola oil, if my memory serves, is actually a fairly fast oil when it is warmed to 130F. (Peanut oil may be a tad slower than canola...not sure bout that) But it is only fast in the initial phase (and really not fast enough for 1095), and then doesn't do all that well for shallow hardening steels like 1095 and W2 once the PN has been reached, and the cooling rate needs to be slowed. As you have witnessed yourself, a perfectly good knife can be made with 1095. But a perfectly bad one can be made, too, if temps and times are not right, and quench medium is wrong.

To get the best performance out of 1095 indeed does require an accurate temperature below 1500F, preferably right AT 1475F, and a solid 10 to 15 minutes soak is needed as well at that controlled temp. How much MORE better is the performance of 1095 over something that is much easier to heat treat, such as 1084? Not much, for sure. Hence the reason why 1084 is usually the much better choice in steel, especially for those beginning to learn how to properly heat treat a blade. Get it to 1500F, no soak, quench in canola.....temper...and you have a fine blade. Do that with 1095, and you'll have a 1084 knife, if you're lucky.

A few reasons why 1095 is not recommended for beginner heat treat:
1. It is shallow hardening and requires a very fast quench for full martensite conversion. This means Brine (risk breaking one every now and again), very fast oil (can be expensive and hard to ship), or canola and the like (not reaching full potential)
2. It's temperature window is extremely tight. 1475F-1500F, preferably around the 1475F mark
3. It requires a soak to get the alloying and carbides dispersed evenly
4. Due to the soak time, a decarb layer will be present (if not taken care of with coatings). Which to inexperienced heat treaters may make them think the steel did not harden at all. It did, just gotta remove the decarb layer.
5. Not all 1095 is/was the same. Varying Mn counts leave heat treaters very frustrated if they don't know exactly the formula involved. This caused some problems in the past on the forums, guys had 1095 that was questionable

There are a few heat treat shops that will not do ANY oil hardening steel due to OSHA regs and other issues with using oil. But there are a few shops that do oil hardening steels no issue at all. Peter's Heat Treating will certainly take care of you.

If using a magnet to determine when to quench 1095, remember the magnet stops sticking at around 1414F. If you quench from exactly non magnetic, you're not getting it hot enough. You need another 50F degrees or so.....AND that soak. And a faster quench than peanut oil.

But you've made a fine serviceable blade from what you had, so kudos to you! Put the knife to work!
 
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Thanks for the encouragement. Just to be clear - even though I don't know much now, if I had known it before I would have ordered 1084 or even 1075/80. But since I have the 1095 already I'm gonna use what I have to get a little experience, and hopefully get a little better at it.

I'm just glad that it's possible for me to make a decent knife with it even if it wasn't the very best first choice.
 
in knives thickness 120-130F canola oil is plenty enough to reach full martensite, of course you are supposed to vigorously agitate during the quench.
1475F is very spot on austenitizing temperature for this steel. As per the soaking time, it strongly depends on the carbides configuration: very fine, well dispersed carbides may only require 5-10 minutes at 1475F, while heavy spheroidized cementite will benefit of +20 minutes at the austenitizing temperature if max hardness is the target.
 
The thing is the only tools that I have to guage the temp of the steel is a magnet and a color chart - the only tool for controling the temp is just moving the blade in and out of the hot zone. I wish I had an accurate IR thermometer so I could get a better idea of steel temp, because by the time the steel is non-magnetic it already looks a little orange to me, but the color chart says orange starts around 1600 - of course the color chart isn't glowing hot so I'm probably seeing it wrong.

What I need is for someone who knows, standing there when I pull the piece out of the forge and say "that looks a little too hot...." And some longer tongs. Really need some longer tongs.

Maybe a better color chart - can anyone recommend one? Or a good $30 ir thermometer - that would be good too.

The thing is at least I know that I can make a knife that will cut with what it have and what little I know. So that's good.
 
David, the color charts are useless. My eyes are 20/10 vision, with what I believe is exceptional ability to distinguish colors. The color charts make me cringe. NONE of them look alike to me. They are basically useless. I have even heard many smiths say that critical heat is red, well to me it is a bit more orange than red. And it gets subjective quickly. Orange-red vs Red-orange. My advice to you is forget about color charts.

Best thing to do, IMHO, when working your system, is to do any and all heat treating at night or at least in the dark (a distant light if needed). That way your eye gets tuned in to the proper "color", and that of course will take time to develop. It is not easy at all, as you know, to get a good even soak at a given temp. Especially on longer blades. Note the color exactly when the magnet stops sticking. You know this is right at 1414F. And you know you need another 60F (another 85F if it is 1080/1084). So just by going another "shade past non-magnetic" (easier said than done), you know you're over the target. The more you do it, the better you get at it. If you overheat it, you'll grow some grain. Not the end of the world. Still will be a decent knife.

Once you get bit by the bug, you'll be chomping at the bit to find some sort of oven at a reasonable price! Then you push some buttons, and then sit back with a margarita while you wait for the timer to go off!

Stezann brings up a good point that I thought about mentioning but decided to let it go. 1095 in thinner cross sections (I would say 1/8" is approaching max) may through harden OK with 130F canola. Maybe. With thinner smaller knives, it may full harden. But there's the point. Will the canola work with 1095? If it is warmed to 130F (not higher not lower), and the knife to be quenched isn't too massive for the canola. If it is bowie sized.....you'll need a faster oil for sure.

I THINK, emphasis on THINK, the speed of 130F canola oil is rated around 9 seconds. When Parks 50 is 7 seconds...you know the canola can't be that bad for 1095!
 
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So that's what I did - dark room, normalized 3 times, heated a shade past non-magnetic (which looked pretty orange to me) and did my best to hold it there for 20 minutes, quenched in 130 degree canola, tempered at 475 f for 1 hr.

BTW, it would have been hard to do without the long "tongs" I made by welding reigns on some slip joint pliers. Something no one mentions.

Then of course I couldn't wait to see if it worked so I cleaned it up on a 320 belt and sharpened it up. Much harder than the experiment quenched in used peanut oil. Takes a good edge, and seems to hold it pretty well - only time and use will tell. But I'm fairly pleased so far. I'll post a picture when it's finished - I'm sure everyone can hardly wait for more "first knife" pictures.

Thanks for all the help.
 
I'm happy to hear you had a good blade :thumbup:
Samuraistuart is right, 1095 needs a lot of speed, and the Parks #50 is the best oil for this steel under every aspect (not only the fastness aspect).
Warmed canola can help when we have no other alternative, and it is quite good many times (especially with thinner blades), but #50 is difficult to beat!!!

The real respect (hence the difficult part) the 1095 deserves, imho, instead of the fast quench requirements, is more related to the risk to overfill the austenite with excessive carbon, overheating...that would be retained austenite in the final product, and i believe it would be more detrimental then having a little pearlite from a less than quick enough quench.
So if my equipment has to be less than optimal i would invest first my money on temperature control and then in the right oil.
 
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Where can you get it in small amounts? A quick search only turns up a lot of people asking the same question? Parks 50 that is.

So if my equipment has to be less than optimal i would invest first my money on temperature control and then in the right oil.

Once I use up some of my stock of 1095 I'm gonna try to invest in the right steel, 1084 or 1075/80 Probably.
 
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David, that is wise choice....1084 with your equipment. You can make a world class blade with 1084 and what you have if done right. About the Parks 50. AFAIK, the only place to get it is Maxim Oil out of Fort Worth Texas. 5 gallons only.

However, there is another oil called DT48 that is supposed to be about the same speed. Sorry, I have no info.
 
Thanks again. Anyway - almost finished with my first one...

first-knife%202-27-2015%203-39-54%20PM.jpg


6 1/4" x 1" x 1/8"

There is a blemish you can see in the metal about half way between the hole and the tip that is on both sides, and won't grind out - I think it is from hitting it with a hammer to straighten it a bit after I annealed it. Does that sound likely? It looks like a ding from being beat on but you can't feel it at all. I'm guessing the metal is compressed or something.
 
Those spots - at least the 3 faint blots - are likely be not fully harden steel (aka hamon).
 
Considering the subject that makes sense.

So apparently the good quench oil is really expensive and hard to get in less than 5 gallons at a time. Canola oil is almost but not quite fast enough to do a good job - while brine will apparently harden 1095 so fast that cracks from thermal shock are an issue.

So how about floating a couple of inches of canola oil on top of some brine then quickly lowering the piece through the oil to start cooling it - down into the brine to quickly finish the quench?

I'm sure I'm not the first person to think of that - so why doesn't it work?
 
You're right, it's been thought of before by many people. Floating oil on top of water is kind of backwards of the quench mentioned. You'd be hitting the oil first, then going into water. You want the blade to be first quenched in water, and then the slower oil.

Even if you had a suspension of water over oil, plunging the blade in will be a disaster. The oil and water will be all over the blade in different areas, just a mess. That's the only way I can put it. And then trying to get repeatable results would be just about impossible.

Nice idea, tho!

I really do think the brine quench is often maligned. Rightly so, it can cause you to lose a blade, even the best smiths. But you might try it with your 1095. Some tips..... A cup of rock salt to a gallon of water. Room temp. Leave the edge maybe a bit thicker than normal, polish pre heat treat to a higher grit, maybe 400, make sure the scratches are running lengthwise, no stress risers. Use a slightly lower hardening temp.
 
Good ideas here ! Remember that 1095 has been around for a long time industrially. So it is possible to do it right. Pay attention to the above statements. doing it by color is a poor choice .I did some tests a long time ago and found even under laboratory conditions I couldn't match the claims some are making.. If you have doubts the use 1080 or better Aldo's 1084.
BTW Wilkinson used whale oil to quench ! Is that cheating ? LOL
 
Before I had a oven and before I found out a lot more about heat treating I used 1095 in my forge . One way to find out if you made a mess of the steel is put it in the vice and give it a little push . I did this to a few of my first blades and they all snapped to expose the coarse concrete like grain structure that I have ever seen . I still have those blades and check them out from time to time.

I finally got some Parks 50 and a digital kiln and I find 1095 to be a pleasure to work with now. I think it makes a very fine blade that has a nice feeling when you are cutting . I do like stainless steel for folding knives and some fixed but I love W2 and 1095 the best .

Keep at it you will get there with dedication and hard work.
 
This may have already been mentioned, but I have not heard anyone talk about 1095 needing a long soak. To the contrary. it typically has almost intentionally included zero alloying elements other than maybe a little bit of manganese. The issue most talked about is the need for a proper quenchant.
 
I finally got around to giving this knife - and thus my first time heat treating - a pretty good workout. By carving a large spoon out of paulownia - which I blanked out with shop tools, and hollowed with a regular spoon carving knife - but everything else I did with this knife. Paulownia wood is pretty soft, but it has a high silicon content so it is fairly abrasive to edges. The knife actually performed pretty well - It sharpened to a good sharp edge - comparable to other carving tools. It also held its edge pretty well - not like a real expertly made knife, but not bad either. A few strokes on a hard Arkansas stone would bring it right back to shaving sharp in a few seconds.

So... this is hardly a torture test - no batoning through pennies, or striking across an anvil. Most likely that kind of abuse would have damaged or broken my first knife. BUT, for my first time heat treating in a home made gas forge, quenching with canola oil, and tempering in the kitchen oven - I feel like I made a completely usable knife.

No doubt my first knife would be better - sharper, tougher, more wear resistant - if I had more skill and better tools - or used steel that is easier to work with. So I have some 1084 that's supposed to arrive today, and I'm gonna save the 1095 until later - maybe my next knife will be better. Which is as it should be I guess.

Gotta go - FedEx just dropped off my steel, and I think my grinder is calling my name.
 
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So, I've been doing some reading to try to better understand what is going on during heat treating, and I have a question.

When a piece like the 1095 in question is not fully hardened because the quenchant is too slow then wouldn't the edge still most likely be well hardened because it is thinner and therefore cools quicker than other parts of the blade? If so doesn't this result in a blade with a hard edge, and a softer/tougher body that is less likely to break than one which is fully hardened - kind of like intentional differential hardening?
 
I believe you are right. While not tech fast enough for 1095 in thin sections (edge) it will get you martensite darn near 100%. There would be a transition zone somewhere above edge. With pearlite mixed in.
 
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