1095 didn't harden

Hello everyone, hope someone can answer some HT questions for me. I've researched 1095 HT for a week now, but I see a lot of variance in recommended recipes.


I'm on my 4th knife now, the others have turned out pretty well, but this is the first time I've used 1095. I just finished a medium sized bowie in 5160 and it worked just fine.


My Mentor keeps trying to learn me to use the KISS principle....so of course I keep choosing more challenging designs and different steels. I ground a 7" blade from 3/16 1095, and he has never heat treated 1095 before (or 5160 for that matter but it worked fine). I performed said research and decided to heat to 1500, hold for 5 minutes, and quench in oil.


However it didn't harden that I can tell. One problem, power failed during the runup in the kiln when the blade was at about 975, when it came back on I just started the ramp again and soaked 5 minutes at 1500 and quenched.


All that said, can anyone tell me what went wrong? I don't know if my whole recipe is wrong, if the interrupted HT cycle is to blame, or what? Also, if that is the problem can that blade be salvaged or should I just start over?


Thanks for your help, and sorry for all the questions.


Jason
 
The very first question..........what kind of oil did you quench it in? That will make a HUGE difference with 1095.

1095 needs a very fast oil to harden........basically, in simplest terms, you need to get the steel from about 1475 degrees to below 900 or so(roughly) in about 1/2 to 3/4 of a second. Yes that is .5 to .75 of ONE second! Because of that, it can be very difficult to harden 1095 properly unless you have a proper quench medium.

Couple that with the fact that you're trying to harden a (relatively) large and thick blade and the odds of success go down even further without a proper quenchant.

I'd question the type of oil first. Second, as a side note, 1500 F. is getting up towards the high side for austenitizing 1095. I certainly wouldn't go above that but 1475 F. would be better, probably.
 
John, thanks for chiming in. Love your work BTW :)

I was quenching in vegetable oil that's been being used for a while and probably in too small a quench pot. Also, the blade was foil wrapped so that tells me I took far too long to quench, which was my other suspicion.

I'm using a paragon oven, does 1095 need to be wrapped? I don't see how you could possibly quench that fast with having to remove a wrap so I'm guessing NO :)
 
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I'm using a paragon oven, does 1095 need to be wrapped? I don't see how you could possibly quench that fast with having to remove a wrap so I'm guessing NO :)

You can't oil quench a fast steel like 1095 in wrap. It acts like an insulator. You can, if the foil co-operates and usually doesn't, take it out, hold it over oil and quickly snipping the foil so the knife drops into the oil. Then it still has to be agitated to keep the vapor barrier away. On fussy steels like 1095, most will not use foil and oil quench leaving some extra meat on the blade to remove after for decarb areas to be removed after tempering. The forge guys either learn to use a nuetral flame in their forge and move things along or they leave a blade "fat" and grind away decarb.
 
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[h=2]1095 didn't harden[/h]

I can't count the number of emails and phone calls I've received over the past few years which could be titled exactly like that!

I'm gona take a chance of getting jeered at here...... Personally, I deleted 1095 from use in my shop a few years ago.....after I found that most of the outfits making it had stretched out the Mn content specs (it was all about being able to produce the steel cheaper).
What that means is that some 1095 these days gives you less then 1 second to get it quenched....and thats physically impossible for most of us. Unless YOU know that a specific seller actually had the batch YOU are buying tested, all you'll get is a standard anaylsis sheet (if they will even send you one) which is gona be a general anaylsis of 1095, and not the actual steel you are buying/bought.

That's a general statement, but there are a couple of resellers whom have their steel "made to order", and I would trust that the 1095 they sell is "good". However, a a rule, 1095 does not get used in my blades. I simply will not waste the time and effort to create a nice blade, only to find I can't harden it. I'm fairly certain that John gets his 1095 from one of the "sources" I mentioned.....but just buying any old 1095 that is available is nothing but a crap-shoot, which is why I won't use it.
 
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Thanks for all the replies gentlemen. Some helpful info there and I appreciate it.

Ed, probably not a bad idea! I ordered steel without doing enough research, thinking that lower cost simple steel like 1095 would be a good place to start. After the HT didn't work, my mentor says "Yep, that's why I use ATS" :)
 
1084/1075 are much easier to heat treat. I have used 1095 from two reputable suppliers, and it requires good temp control, and a commercial fast quenchant or if you are willing to risk it, brine. I find W2 gets a more dramatic hamon, and for kitchen knives, Hitachi White has much more curb appeal. So, for me, it has a difficult heat treat with lower desirability. I will use it with 15n20 for damascus in future though. Did you normalize and thermal cycle? That can help get everything evenly distributed in the steel. The bottom line is you need the proper quenchant speed to get past the temps where pearlite will form, approximately 1209f to 900f. I too stay below 1475f for the high carbon steels.
 
So, anyone want a few feet of 1095 from Jantz LOL

you have a kiln so you have half the battle won! You can control your heat!

Another quench option is brine for three seconds, then into the oil to finish. It's riskier, but will get you past the nose, and the second half of the quench will be slower, and more forgiving.
 
I spent a few minutes today going through Kevin Cashen's threads on heat treating. I'll probably only have to read them about 5 more times before it sinks in...

I think I will try to HT the blade again, after ordering proper quenchant. Might as well, it's already ground and I sure can't make it worse :lol: One question, since I do have a kiln would ya'll suggest normalizing and /or annealing again before running another heat treat cycle? Or should I just re treat and test?

I appreciate all the input everyone, it's nice to be part of a helpful community. Hope I can pass it on some day.
 
It never hurts to normalize and grain refine. It's a good idea to use foil for this to prevent decarb. You could just re heat treat, but it's a good idea to learn to do the best you can early on.
 
It never hurts to normalize and grain refine. It's a good idea to use foil for this to prevent decarb. You could just re heat treat, but it's a good idea to learn to do the best you can early on.

Ironically enough, in this case it can hurt. I'll explain in a moment.

First, how do you know it didn't harden? Did you hardness test it? Where? If on the handle or full thickness spine for a 3/16" thick blade, you may well be right. Vegetable oil is going to loose you some hardness from the start, as much as 3 points, 63 as quenched vs. 66+ if fully hardened. Take a test piece and try a brine quench. The amount of salt can vary, but I think 10% by weight is a good starting point.

Ok, the irony mentioned above. If you do some grain refining steps on 1095, like multiple normalizations at successively lower temperatures, or multiple quenches, then the grain size will go down, and so will the time window to harden it. Finer grained steels require faster quenches to get them fully hardened, especially in steels like the 10xx series, where there are no alloying elements to help out.

Instead of trying to quench in water, you could try vegetable oil and do some odd (for most makers) heat treatments to enlarge the grain size and allow a slower/non-ideal quench to harden the blade. This is sure to get a lot of odd looks.
 
Ironically enough, in this case it can hurt. I'll explain in a moment.

First, how do you know it didn't harden? Did you hardness test it? Where? If on the handle or full thickness spine for a 3/16" thick blade, you may well be right. Vegetable oil is going to loose you some hardness from the start, as much as 3 points, 63 as quenched vs. 66+ if fully hardened. Take a test piece and try a brine quench. The amount of salt can vary, but I think 10% by weight is a good starting point.

Ok, the irony mentioned above. If you do some grain refining steps on 1095, like multiple normalizations at successively lower temperatures, or multiple quenches, then the grain size will go down, and so will the time window to harden it. Finer grained steels require faster quenches to get them fully hardened, especially in steels like the 10xx series, where there are no alloying elements to help out.

Instead of trying to quench in water, you could try vegetable oil and do some odd (for most makers) heat treatments to enlarge the grain size and allow a slower/non-ideal quench to harden the blade. This is sure to get a lot of odd looks.

From what i understand....in order to get the grain SO SMALL that hardenability (depth of hardening) is so small that it will NOT harden at all....it requires many many many cycles. Probably more cycles than the average knife in heat treat is going to see. This is noticed by guys who do lots of hamons on W2 and 1095. Too many cycles will push the hamon close to the edge.

If you are using vegetable oil on 1095, you might look into that as the problem. 1095 must have a super fast quench. If you can't do the Parks 50 route or similiar (Dt48), brine is about your best bet. Or brine for three seconds and then into oil. And with 1095 remember that if your edge is a thick cross section....that is NOT going to help. Make sure your edge is around .030" or so. If it is a full 1/8" or so, depending on heat/soak/quench it may not harden in the center...where the edge will be.

I would highly suggest what Warren mentioned.....normalize that dude and re-try it. Bring it up to about 1650F and equalize (this will re-enlarge the grain somewhat), then air cool only. Do that again at 1550F. Do that again at 1450F. Now the grain has been brought back down. Time to harden.....1475F (keep below 1500 if possible) for 10 minutes and into brine or fast oil. Canola is just not going to work well with 1095....so don't use it...unless you go into brine first, and then into the canola. 1095 needs the soak for 10 minutes or so....otherwise you'll have 1084 after the quench.

Also, remember that hardness is a factor of many things. One thing that WILL need to be taken care of with 1095 after the heat treat is decarb. There will be a layer of carbonless steel about .005" thick around the blade that must be sanded thru before an accurate reading can be taken. If you try the file test to see if it skates after the quench, and the file digs in.....it is likely the blade did harden fine...but you bit into the decarb that must be removed. Get that layer off of there, and underneath should be hard steel. File tests are good, they don't tell us all. Rockwell tests are good, they don't tell the whole story either. Just remember to deal with the decarb before you think you messed up!

(carbonless steel. that is an oxy moron isn't it?)
 
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Yes for this blade it looks like the delay from foil is the culprit. Still, shrinking grain size has some disadvantages. It would harden, but maybe not the way you want.
 
(quote) If you are using vegetable oil on 1095, you might look into that as the problem. 1095 must have a super fast quench. If you can't do the Parks 50 route or similiar (Dt48), brine is about your best bet. Or brine for three seconds and then into oil. And with 1095 remember that if your edge is a thick cross section....that is NOT going to help. Make sure your edge is around .030" or so. If it is a full 1/8" or so, depending on heat/soak/quench it may not harden in the center...where the edge will be.

I would highly suggest what Warren mentioned.....normalize that dude and re-try it. Bring it up to about 1650F and equalize (this will re-enlarge the grain somewhat), then air cool only. Do that again at 1550F. Do that again at 1450F. Now the grain has been brought back down. Time to harden.....1475F (keep below 1500 if possible) for 10 minutes and into brine or fast oil. Canola is just not going to work well with 1095....so don't use it...unless you go into brine first, and then into the canola. 1095 needs the soak for 10 minutes or so....otherwise you'll have 1084 after the quench. (quote)

I would not be so quick to completely dismiss the use of canola oil. There is "ONE" well known maker who has done pretty well with using it in the past, and although even he admits it is not the best, it seems to produce a very acceptable blade. This "ONE" particular maker, if memory serves me, switched to Parks #50, but produced some very decent results using the canola. Again if memory serves, the main reason this maker switched to Parks 50 was because canola breaks down too fast, and has to be replaced too often. Brine is usually reserved for thick pieces of 1/4" or more in 1095. With thinner sections, as in knife blades, the fast oils are preferred to reduce the risk of cracking. In test results I read years back, canola was only one, maybe two Rc points behind Parks 50. Good enough to insure a blade of acceptable performance. Not the best, but acceptable.
 
LRB....good points!!!! "Not the best but acceptable" is a GREAT way to put it!!!! This is what I gather from reading you smart guys......canola oil is a fast quench (probably around the 11 second mark...not really fast like Parks 50 but fairly fast). However, a commercial oil is manufactured to not only provide the proper speed to get under the pearlite nose in the proper time frame, but it continues to cool the steel after the PN is reached at the right speed. Canola oil may be fast enough to get our carbon steels under the PN in time...but the secondary part of the quench which requires a slower controlled cooling rate....canola (or peanut, or mineral, or etc) cannot do.
 
I find myself in this predicament fairly often. As an example, do you buy a $180 pail of quench oil to harden the steel I bout for $15.00, or is it easier just to buy a new bar of steel? Last year, I was looking up what welding rods I could use to save an O1 blank I cracked, about $3.00 of steel, but a small pack of the rods was $45.00. I do this all the time. Its silly, but I have to shake my head and rethink things sometimes.
 
I find myself in this predicament fairly often. As an example, do you buy a $180 pail of quench oil to harden the steel I bout for $15.00, or is it easier just to buy a new bar of steel? Last year, I was looking up what welding rods I could use to save an O1 blank I cracked, about $3.00 of steel, but a small pack of the rods was $45.00. I do this all the time. Its silly, but I have to shake my head and rethink things sometimes.

cut your losses and buy a bar of 1084(aldo) or 1080+(aks). you have a kiln so you can maintain temperature, both will harden just fine in canola oil. the steel is from a known source, so you should be able to get repeatable results. JMHO
 
I agree with Scott. 1080/84 with a good HT is as good or better than 1095 with a poor HT. Either of these steels Scott mentioned are almost fool proof to HT well.
 
I agree with the 1080/1084 suggestion too.

Just to be clear, I wanted to point out that 1080+ and 1080 are not the same thing. That's why I like calling 1080+ by it's real name....80CrV2. It's less confusing.

While 80CrV2 is, in my opinion, easier to heat treat than 1095, it requires a bit more care to reach full potential than 1080. Meaning that if you heat 1080 to 50 degrees past non-magnetic with no soak and quench you will likely come close to maximum potential for that steel. On the other hand, if you heat 80CrV2 to 50 degrees past non magnetic with no soak and quench, you very likely will NOT reach maximum potential of that steel.

Also, in my experiences, from a performance aspect, 80CrV2 heat treated to its maximum potential will blow 1080 heat treated to its maximum potential out of the water in ALL categories.

I just wanted to be clear that there are differences between 1080 and 80CrV2 (1080+).
 
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