A2 as a core steel for a san mai. HT question.

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Hey guys. I was wanting to do a san mai billet with A2 core and carbon damascus cladding. a 1080/15n20 mix most likely for the cladding. :les:

I dont think I will have a problem with the forge weld. or drawing and forging the bar. Yet am not sure about the Heat Treat.

I have never worked with A2 so I am unfamiliar with how it acts and or if it will play well with my carbon cladding. Ideally, I would be heat treating at a higher temp with a longer soak time to get the results I want from the A2 core. I plan to do this in a SS wrap as to keep the decarb to a minimum. :34:

I guess my question is will the A2 and carbon damascus combo make it through Heat treat without self destructing?

Any advise or input is welcome. :3:
 
Ultimately you'll just have to try and see. That said, if you air cool the blade, the A2 should expand while the other portions would already be in pearlite form, thus ductile enough to take some movement. It all depends on how good the weld is, how thick the portions are in relation to each other, and what your HT procedure is. The good news is the air cool to harden A2 should give minimal shock to the blade. You'll probably get some warping though, depending on how thick the core is in relation to the sides.
 
This is one of those things that I would put in the "Don't do it" folder. You're trying to mate two materials with widely different expansion/contraction properties......and although you MIGHT get them to weld, it's gona fight you the whole way, and it's gona be more trouble then it's worth.
 
Ed has it right, I did this some years ago and had the San Mai all forged out and on the final normalizing heat it went "POP" as it cooled on the anvil. Welds were clean and it still went south, haven't done any more since.


Peter
 
Good morning. Thanks guys for the input. I sorta figured that this was what I would hear. But wanted to double check here B4 even attempting it.


OK so how about 52100 core?
 
Just to add in another opinion, isn't the ideal of san mai supposed to be a tough cladding over a hard, wear resistant core. A2 is primarily respected for it's toughness IIRC. Secondly, when you HT something mixed, you generally HT to the performance alloy - in this case, the A2, but the Higher temps, long soak and air quench are going to leave your 1080/15N20 as little more than coarse grained pearlite / RA. Neither Damascus nor san-mai are areas that I have any expertise in, but I'm curious why you would choose that combination. I'm also curious what the experienced makers would suggest as good combinations for san-mai and why. Thanks for raising the topic.
 
This is a topic I am curious about as well. Making steel decisions that minimize carbon migration from the high carbon core is what I would like to learn about.
 
Knifemaker ca.

The core was one of the options my client requested. I at the time said I would keep it as a option but that my thought was I would have to adjust the core to another material that will play nice with the cladding. To me a Damascus cladding over a mono core is purely aesthetics.

I would Heat treat to accommodate the core material no matter what it is. Yet as Ed and others have said. this combo will be a problem and it just reassured me of what I already figured.

Thanks for the input and I look forward to hearing what others think is a good combination and why.

I have had good luck with 1095 core with carbon damascus cladding.
 
52100 would be an excellent choice of core materials....taking into consideration 52100 is sensitive to overheating......meaning that once you have things forged to shape, make sure you run it through 3 thermal cycles before annealing, and you should be OK. A "trick" that I have learned over the years with 52100 cores in San-Mai, is to heat treat in a salt tank...but rather then go to the austinzing temp of 52100....set the salt tank about 75-100 degrees below the austinizing temp, and allow it to soak for 3-5 mins. This will get you more banite then austinite......making the blade very tough. If you finish with a convex edge, leave the convxe slightly more obtuse then you would with a fully austinized blade, and you'll be amazed at how well is cuts, and how tough it will be.

I don't often share that info, simply because most folks know I am dead set against soaking ANY of the "forgeable" steels during heat treat, but in this case it produces very noticable advantages.
 
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Ed, Thank you for sharing and for helping us Dogs when you can.

I think I will order in some 52100 and give that a go for this project. I will also try to follow your recommendations both with the soak as well as the grind and cutting bevel.
 
Highly recommend 52100 core, it makes an amazing high performance knife. Wad up a bunch of nickel damascus for the outside and you've got a show stopper, beauty and brawn.


Peter
 
So Ed you're soaking for the 52100 core at 1375 to 1425 F? Why are you against soaking?
 
Thanks for the info. Here is the blade after a quick etch. :) I went with a 1095 ore and carbon damascus.
 

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Why are you against soaking?

Although "soaking" has become a widly accepted practice within the knife making world over the last decade, which I attribute to the "instant gratification" generation, experience and experimentation over the past 20+ years has taught me that it often does more harm then good. Personally, I think it's because "data" is so much more available, and most folks simply are unwilling to take the time and effort to ensure the "data" they depend on, is actually good.

Now before somebody sends out the "lynch mob" for me, let me explain.....first and foremost is the simple fact that EVERY heat treat book or manual out there always bases the included data on a "one inch cross section" of the given steel type. Can't speak for anyone other then myself, but I have never produced a knife blade that is 1 inch thick. (if you look closely at just about any book or other reference material about heat treating, somewhere you will find (usually in very small print) a statement that says something like... All data based on 1" cross section.
Years ago, after discovering that statement, it made me start questioning the data contained in heat treat manuals/references, and just how much of it was truley relevant to knifemaking......it also lead me into testing and experimenting towards the goal of finding my own answers. After several years, and a file cabinet full of test results, I came to realize that there is a major difference in the knife steels that I use (those I consider "forgeable") between allowing a blade to "soak", and not "soaking", which I believe is due in no small way to the cross section sizes we use in knifemaking, versus the 1" cross sections used to acqure the majority of available heat treating data.
The differences in some steel types can be minor, but in other steel types such as 52100, soaking at or above the austinizing temp basically causes the grain size to "explode" versus allowing the blade to just reach it's austinizing temp and then quench, which ALWAYS returned test results showing significantly smaller grain size, as well as other favorable aspects.

Each steel type manifests some differnt concerns for me involving "soaking", but generally speaking, as with most things concerning knife blades, it's a matter of "trade-offs", and in my opinion, for my knives, the detrements of "soaking" are not acceptable versus not allowing a blade to "soak".

I've had many discussions, and even some heated ones with folks who want to point out that "all the accepted data" states that soaking is appropriate, and should be done. I'm not out to force change upon anyone, nor to dissuade others from doing what they believe in, I'm simply secure in my position that "soaking" isn't something I choose to do to my blades, and the "data" that I've compiled proves it for me.

In a nutshell it's really all about the performance of the finished knife, and I believe that each individual must determine for themselves what is, and what is not acceptable. Simply stated, I can produce a a blade that performs "better" by not "soaking" then I can from the same steel that is allowed to "soak", in just about every aspect that matters to me and my customers.

Kind of long winded, trying to put 20+ years of experience into a few paragraphs, but that's the reasons I do not "soak" during heat treating.
 
... I've had many discussions, and even some heated ones with folks who want to point out that "all the accepted data" states that soaking is appropriate, and should be done. I'm not out to force change upon anyone, nor to dissuade others from doing what they believe in, I'm simply secure in my position that "soaking" isn't something I choose to do to my blades, and the "data" that I've compiled proves it for me...

I know that Ed and I agree that folks being heated or hostile over steel info is not only silly, it is entirely inexplicable. Steel is steel and people are people, we need to remember that more often in this business, and folks should be able to make their knives any way they like; after all, what are we going to do, send the knife police to peoples shops to enforce the rules of making?

Instead we just have conversations, conversations where we present our information and allow others to determine which information works better for them. This is one example, I just spent a great weekend with Ed up in Alberta and our years of making, study and compiled data say exact opposite things on this topic, but I’ll let folks decide which data works better for them. I have no emotional investment in austenite solutions in blade steel, so it is neither here nor there for me, but Ed is a person that I like. Keeping that difference in mind only makes sense.
 
There ya go folks....Kevin's response shows just how lucky we are to have him as a moderator. In other venues there would have been a "war of words", but being the true professional and friend that he is, Kevin and I can disagree without taking any of it personally. Just goes to show you that this business isn't really about knives.....it's about people.
 
Thank you gentlemen for sharing and communicating with us on this thread. Interesting how different your test results are on this subject. Yet refreshing for me to know its more about the Journey then the destination as both of you get to the same place but by a different road.

I respect and appreciate you both..

God Bless Ya


Stay sharp
Randy
 
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