Using new 1095, all sorts of problems...

[jcoon8283]

For almost the last year I have been exclusively using 1095 from Jantz to make my knives with almost no problems at all except that two knives out of the 78 I've made so far had minor cracks in them. I have heard a lot about the NJ Steel Baron's 1095 being a superior melt to what else is out there, so I thought I would give it a try. Right off the bat I was having problems with it. I started cutting out 7" blanks and every time I got to the end of my cut into the bar with the jigsaw, the very end of the bar at the start of the cuts were passing over/under each other in a x shaped fashion. After I cut out the blanks, in light of the warping I thought that the bar was under a good amount of stress so I normalized the blanks (1600* in the kiln and out to air cool) then annealed them (1550* in the kiln then shut it off to cool over night).
I made four tantos of various lengths as test knives to see if my recipe for tempering the Jantz 1095 would work for the Baron's 1095. Well, it did not. Although I didn't expect it to, mainly I used my old recipe as a jumping off point. The edges of the first two that I finished failed to pass the wire edge test, but only just barely, so I stopped work on the rest. I had to break out the 14x pocket microscope to tell that the edges on both knives had rolled over and didn't chip out, it was that small a deformation. So usually in this situation I believe one would have to re-quench, and temper at a lower temperature which would be no problem for me. But herein lies my problem. I differentially heat treated both these knives with clay, and I have no idea what to do next now that they've failed the test. I struggle sometimes learning the metallurgy side of the why we do what we do when heat treating the steel. So, when I re-heat treat the knives, to retain the differential ht within the knife can I use clay again, or will there be some sort of retention of the old hamon line showing up after re-ht? Or, should I, for the time being, give up trying to solve how to differentially ht them and just re-quench and dial in the tempering temps? Sorry for the highly verbose post, but any help you guys might offer would be much appreciated. Thanks!!!

[WBE]

A little more info on your process would help in figuring out your problems. What is your quench? At what temp are you quenching? Are you soaking before quench? Did you do a cycled lower temp normalization after the initial 1600? heat and slow lamellar anneal which in itself is a problem for hypereutectic steels? Just a side note. If you hold down alt, then punch in 248, you will get the degree symbol.

[Ray Rogers]

If you repeat the HT process with the clay it should create a new hamon, without the clay should give no hamon....

[Doug Lester]

First of all, I'm pretty sure that Aldo's 1095 comes annealed so re-annealing it is not going to do anything, except cause problems with coarsening of the carbides which can lead to difficulty machining and edge chipping. If you feel it's necessary to anneal hypereutictic steel, like 1095, a sub critical anneal, sometimes called spheroidizing, would be better.

Second, if you had to pull out a magnifier to check the indentation you're probably chasing phantoms. Something that small could also be from a slight difference in the way that you ground the edge.

Yes, you can go back and repeat the heat treatment with the clay without any problems. When you austinize the blades all those crystal structures that cause a hamon/differential hardening will be converted back to austinite and be erased. If you want to make sure, you could normalize again-once. It is possible to over refine the grain in simple steels such as 1095.

Metallurgy can be a struggle. I have four texts on the subject and I still have to ask the experts. One good source, and a free one, is are stickies put up by Kevin Cashen. He's one of the few knife makers who is able to do microscopic analysis of his blades. Go to KnifeDogs.com>Knife Makers Area>Heat Treating Forum on KnifeDogs. He is the moderator there and has put up some sickies concerning metallurgy. Right now he has an article on annealing down in the regular section that he has posted for comment and hasn't, as of yesterday, indexed yet. It's worth downloading to your computer and printing out for a quick reference.

Doug

[WBE]

The above is excellent advise.

[jcoon8283]

WBE, my whole process went like this. Cut out blanks, 1-1600? normalizing cycle, 1550? lamellar anneal, rough grind of profile and began setting bevels, 3 normalizing cycles, 1 each at 1500?,1400?, and 1300?. Finished setting the bevels and took out to 400 grit in prep of ht. 1500? ht with a 7 minute soak, into 6 gallons of parks #50 that sits directly below my kiln for a count of ten, then into the still air to finish cooling.

Ray, thanks that was the info I was looking for!!

Doug, I was under the impression that Aldo's 1095 was annealed to begin with as well. Never have I re-annealed a piece of steel I bought from a supplier, but, as I was cutting Aldo's bar into blanks and noticed the open ends of the cut I was making were passing over themselves I assumed that is was stresses in the steel that was making it warp over itself like it was, and that it would be a good idea to relieve those stresses. I didn't realize that a lamellar anneal would lead to problems. I only have a dial control on my kiln and don't have a programmer so to do a sub critical anneal for me would be on the tough and time consuming side from my understanding on how to do it. So, did I royally screw up by giving them a lamellar anneal and possibly coarsing the carbides to the point I should throw out the steel and start with new or could it be fixed?

When I subjected the knives to the wire edges test I could see with my naked eye that the edges were deforming, I just had to use magnification to tell whether is was chipped out or rolled over.

Kevin Cashen is a name I am familiar with and thanks for the lead! I first saw one of his posts in the "How the hell do you heat treat 1095?!" thread over at blade forums. Ever since then I have been reading everyone of his posts that I can find.

Which is why I am now a little confused by WBE when you said "Did you do a cycled lower temp normalization after the initial 1600? heat and slow lamellar anneal which in itself is a problem for hypereutectic steels?"
Could you please tell me why it is a problem for hypereutectic steels because here http://www.bladeforums.com/forums/sh...at-treat-1095-!
Mr Cashen mentions in the fourth paragraph of his first post that a lamellar anneal is fine. So now I am little confused on that aspect, But I think as far as my present dilema goes I'm going to re-ht without clay until I get the tempering temps dialed in. Although I will say this, I hope Aldo's steel is worth all this hassle over Jantz's 1095, because from day one the Jantz steel was an absolute dream for me in my shop to work with and ht. I guess I'm learning that if it's not broken, it doesn't necessarily need fixing lol. I just want to produce the best knife I possibly can and I am always looking for a better way to do that and if I could start by using the best steel possible then... Anyways thanks for the help gentlemen, you have been most helpful and I appreciate it more than you know!!!

[Doug Lester]

My suggestion is that you correspond directly with Kevin. He has often said in his posts that he is open to it and I've corresponded with him before. He's a great guy and good about responding but remember he does have a life, unlike us retired people, and is not always able to respond on a daily basis.

Also I believe that his statement is that there is is no problem with lamellar annealing if all you will be doing is grinding. Any other machining operations can be a problem.

There is a problem with 1095 that is not seen to the as much with other steels and that's it's manganese level, as Kevin alluded to in his post. I looked up a supplier and noted that the typical assay for the 1095 that they carry can be from 0.3-0.6%. The high end of that range will give a steel that is reasonably deep hardening and would probably harden in oil. If you go to the lower end you will have to have a real aggressive quenchant, such as Parks #50, water, or brine, to beat the nose of the curve to prevent a slack quench. The problem with 1095 is not that it's difficult to heat treat but that it can be highly inconsistent from batch to batch. There are commercial knife makers who use 1095 extensively for their blades but they're large enough that they can order a melt with specified manganese, carbon, or other alloying elements. That's exactly what Aldo did.

Doug

[EdStreet]

As for the Mn content variation goes yes the range on 1095 is .3 to .5. However one supplier being 'better' or 'superior' than another is highly debatable and there are currently many misconceptions out there as to level variations. Some suppliers will claim that chemistry levels on their stock is spot on every single time and if you buy it elsewhere they will change grossly. This is just simply not true, chemistry levels can and *WILL* change from between batches and even with in the SAME batch.

What many suppliers do is they look at the spark analysis of EACH batch they buy and if it's not in their acceptable levels they will not buy it. Others will just sell what they can get their hands on. I can tel you that Aldo at NJ steel baron is very picky on what he obtains. How do I know this? Because I had a good discussion with him this week about this very subject.

One of the common methods used to create steels (and other metals): The buckets on the melt deck are cleaned out. Recycled metals in bits and sections are put in the pot to melt and samples are taken when they are melted, the sample is sent to the lab for a spark analysis where they determine what is low and high. The results are printed out on the melt deck where they look at the numbers then add bags of whatever element that is needed to reach the numbers. Another sample is taken and the process repeats till the results are in the acceptable range that is needed. Then the pot is pulled out, poured and worked however is needed.

From this you can clearly see how and where/how changes in the same batch and batch to batch happens.

I am curious what you are quenching in? I know that quench fluids have to be filtered good to keep your curves in line and with more impurities the worse the curves are.

I would like to post a quote from Ed Caffrey to me about 1095 and quenching times.

Generally speaking, for a piece of carbon/alloy steel to harden, it must go from it's critical temp, to 400 degrees or less, in 6 seconds or less. With 1095 that contains the lower end of the Mn content, that 6 second time is reduced to less than one second in some cases.....which is physically impossible for most bladesmiths to achieve.

Does anyone know what process jantz supply puts their 1095 steel thru before selling it? From the sounds of things the condition you get the steel in is quite different tho it is the same steel.

[WBE]

The main concern on quenching 1095 is to drop the temp, below 900? in about one second. That requires Parks #50 oil, or an equivalent. The quench temp should never exceed 1475? in a simple hypereutectic steel. That initial temp change is what it takes to beat the pearlite nose with 1095. Beyond is much less important. A lamellar anneal is a waste of time with this steel. It needs a spheroidizing anneal to prep it for working on. You seem to be jumping around in the process. 1600? will bring everything into good solution. From there you can air cool then go again to 1450/75?, then to maybe 1400? for another cycle. This will reduce grain size. Then you can take it to 1470/75?, soak maybe 8/10 minutes and quench. 1500? is a tad high for this step. You really need to get details from Kevin. He is the master of this.

[Doug Lester]

I talked to Aldo at a hammer-in two years ago and what BlackNet said about chemical differences between melts is true. A smelter cannot hit the same mark each and every time, especially when the charge is made up of recycled steel and iron. Aldo said that he was very lucky with the melt that was made for him that it came out very close to the target specs. Next time he may not be so lucky. Each melt will be different to some degree and "typical analysis" is wishful thinking more than anything.

The W series steels are a good example. First of all the allowable carbon content varies widely. Like from 0.60-1.15% That alone can make a huge difference in how you handle the steel and it's why many knife makers avoid it. Originally W1 was basically the the equivalent of the 10XX series of steel from 1060 to 1095, depending on the carbon content of a given melt. W2 was supposed to be the same but with just a little vanadium added for grain size control. Now with the way all the steel made in the States is recycled both are found with more than a trace amount of vanadium, tungsten, and chromium in them listed on their typical assay.

If you really want to know the chemical composition of your steel you will need to ask for the actual assay of the lot that you are purchasing from if the supplier has it. If all they can supply you with is the typical analysis or target analysis then the best way is to send a sample off to a lab and hope that all the of that type that you bought is from the same lot.

What it all means is that you have to be ready to check your all your knives for proper hardening regardless of how tight you are on your heat control and be ready to modify your heat treating routine with each batch of steel that you purchase. Possibly with each bar of steel.

JCoon, I'm not understanding what you mean by the ends of the open cuts crossing over each other. Can you post a picture of what you're seeing?

Doug

[AUBE]

Originally Posted by jcoon8283

But herein lies my problem. I differentially heat treated both these knives with clay, and I have no idea what to do next now that they've failed the test. So, when I re-heat treat the knives, to retain the differential ht within the knife can I use clay again, or will there be some sort of retention of the old hamon line showing up after re-ht?

Or, should I, for the time being, give up trying to solve how to differentially ht them and just re-quench and dial in the tempering temps?

When you do a hamon line on a knife, then have to re-heat treat it again, sometimes you will get a "ghost" hamon leftover from the last one. This happens above the new hamon line, where the knife was covered with clay. Something about the clay coating sometimes keeps the crystals in the hamon from completely going away. Sometimes it uglies the knife up, sometimes you can get pretty interesting effects. If the new hamon is put in place above the old hamon then the old one should be erased.

My advice would be to do a test blade, skip the hamon and just through harden the blade, and skip the anneal. When you are having trouble with a process its best to go back to basics, then add each process one step at a time....you get a better idea at what stage your problem comes about.

[jcoon8283]

Ok, we'll see if this works, I've never posted a picture here so here goes. My skills in paint are pretty weak, but since I don't have a picture of what I was describing I thought I would draw a picture of it. Imagine you are looking at the bar from the top, with the bar clamped to a bench. In the picture, #1 is what a bar of Jantz 1095 looked after I cut into it, no change at all save for the cut made into it. But, #2 shows what happened when I cut into Aldo's 1095. The cut stopped at B, and by the time I had gotten there, the ends of the bar where I started cutting had passed over/under each other. There was not such pronounced curving on bar #2 as in the picture I drew, but, like I said, my paint skills are weak. But, none the less, the picture I drew is pretty spot on to what happened in real life.

[AUBE]

Originally Posted by jcoon8283

Ok, we'll see if this works, I've never posted a picture here so here goes. My skills in paint are pretty weak, but since I don't have a picture of what I was describing I thought I would draw a picture of it. Imagine you are looking at the bar from the top, with the bar clamped to a bench. In the picture, #1 is what a bar of Jantz 1095 looked after I cut into it, no change at all save for the cut made into it. But, #2 shows what happened when I cut into Aldo's 1095. The cut stopped at B, and by the time I had gotten there, the ends of the bar where I started cutting had passed over/under each other. There was not such pronounced curving on bar #2 as in the picture I drew, but, like I said, my paint skills are weak. But, none the less, the picture I drew is pretty spot on to what happened in real life.

Then yes I would say there is stress in the steel, and that a normalizing cycle would be a good idea. Odd to see it bend that direction though, I haven't had that one yet. Usually for me it would bend along the thickness of the steel, not the width.

[Doug Lester]

Ok, now I see-said the blind man talking to his deaf son on the telephone. Sorry, I can get a little strange(r) on towards bed time. Yes, I think that you are looking at the results of some stresses that have built up in the bar. I would not, however, try to remedy this with annealing but with normalization. By the time our steel gets to us it has been rolled out, stacked, banged around on a pallet, sheared and, possibly, ground and stress can build up that needs to be relieved. It might occur but I would not expect this to happen with each piece of steel and similar things may happen with steel that you purchase in the future. Just part of the game; like putting a straight blade into the oven to temper and have it come out warped even though it's been normalized to relieve stress.

Doug

[metal99]

Hope you get this figured out man. I am just tempering a 1095 blade right now. I had some issues with this one. I was going for the good old hamon and just couldn't get it to fully harden so I water quenched it and now the hamon is almost to far up the spine for what I was going for. I was pretty nervous as that blade that has taken me so many hours to make went tip first into that water but it turned out I honestly think you should try a water quench on a scrap or something you don't overly care about. Or maybe the other guys nailed the issue about the annealing. I'm just going by my very limited experience with 1095 or any steel for that matter. Please don't think that I'm trying to be a know it all, I'm just going by what I have tried and tested myself and that's not a lot.