Laminated steel

H

Hesparus

Joined
Oct 31, 2004
Messages
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What's the deal with laminated steel? Does it stand up to the hype I've heard about it and, if so, what's so special about it? How about folded steel?
Next to, "Do you harden and temper them?", "Do you fold the steel" is probably the most frequent question I'm asked when I tell someone I'm a knifemaker. When I tell them, "no", they always get this dissapointed look about them. Unless we're talking damascus, I have never heard someone here mention that they fold their steel and I figure that we've got enough skill and knowledge here that if it did anything someone here would do it. So what's the deal?

- Chris

p.s. I was under the impression that if one folds steel more than, like, 30 times the steel starts to deteriorate. I did the math (2^30 = 1,073,741,824 layers. If your blade is 1/4" thick, then .25"/1,073,741,824 = 2.33x10^-10" per layer) and it looks like if you fold it more than that, then each layer starts to become less than on atom thick. It would seem that this would make the iron carbide molecules break down or become irregular in their arrangement, which would be bad if you wanted it to be sharp and strong (both important qualities of a blade, I'm led to believe). Is there any truth to this, or do I not have a clue what I'm talking about?
Second, I met a guy who told me that he had a katana that had been folded 2000 times. Is he as full of crap as I think he is? 2^2000 = 1.14x10^602, at 1/4" thick, each layer must be 2.18x10^-603" thick, which is undoubtedly thinner than anything in the universe including electrons, nutrinos and the mythical tachyon. So if each layer is thinner than the most fundamental particals of matter an energy, what are they made of?

edit: p.p.s. Now that I think about it, it's not thinner than an electron. Electrons are consitered to have no volume and therefore are infinately thin. I might also be wrong about nutrinos and tachyons. You get my drift, though.
 
Chris: What have you been smoking?????? You got to come down here and make up a billet of damascus with me. You will see the light. :eek: ;) :D
 
George ,give him some of your relish ,it will clear out his system.....Laminated blades work well. They have a hard wear resistant core with a softer layer on each side .Scandinavians have used it for 100s of years ....Folded steel has many myths about it and George can straighten you out !!
 
While we're on the subject, has anyone looked into laminating a ductile stainless over something like 52100? I would think that would permit better corrosion resistance, strength, and edge than even S30V.

-Allin
 
You'll have to forgive me if my questions don't make any sense, are misguided or are extremely elementary. So let me try to start from the beginning.
When I say "laminated steel" I mean like the San Mai III stuff that Cold Steel uses. It makes sense that it would be more durable than an un-laminated steel because the low carbon steel adds tensile strength and plyability. But how does the increased edge retention happen? I know a guy who says that he's used a laminated Cold Steel knife for 25 years and never sharpened it and it will still shave his arm. I know he's full of crap but I don't know anything about the steel to back it up with.
As for folded steel, I don't mean damascus but the same steel being folded and forge-welded. You know, like they always talk about in the movies. I've only ever met one person who has ever done it and he didn't seem to know much at all about knifemaking (but he knew more than I about forging so I had no reason to doubt him). Now, I don't get the point of this and I've never heard the athourities on blade forging say anything about it. So my questions are, Does this exist? If so, what's the point? And, If not, where did the myths come from? I can't remember where I heard the bit about folding more than 30 times. I think I read it in Jim Hrisoulas' "The Complete Bladesmith" but I just skimmed through it and didn't find anything. The math does work out, though. And speaking of math, I apologize for that little bit at the end of my initial post. I don't know what came over me. In any case, all of this has been bothering me for a few days, now, so I'd appreciate any help with it.

- Chris
 
As far as the laminated san-mai type blades having better edge retension, well the only way I could see that would be if you don't have to temper them as much as a monosteel blade. Perhaps the cushion of the outer layer permits a higher RC of the edge steel therfore equating to higher edge retension. I'm afraid I haven't fooled around with san-mai blades at all.

The whole folding thing has come about from the hype associated with true Japanese swords. A Japanese smith begins a sword billet by building up a stack of tamahagane, broken steel and iron bits fresh from the smelter that have been sorted according to carbon content and appearance. This initial billet is welded together and then must be refined. Drawing the billet out lengthwise and folding (and widening the billet and folding from side to side) and rewelding over and over actually serves to both refine the steel by working out impurities and to even the carbon distribution. The Japanese smith will further adjust the carbon content of the steel by working the blade in parts of the charcoal fire that are either carburizing or oxidizing.

When dealing with any steel source other than raw tamahagane there can be little point in folding the steel to such extremes, UNLESS the goal is to make a steel that resembles the grain structure of a Japanese sword by making high layer low contrast welded billets. Folding and rewelding a monosteel of any kind over and over would only serve to lower the overall carbon content of the steel.

Did that help some?

Edited to add: I meant to mention the actual layer count of most Japanese swords or average number of folds but I can't recall off the top of my head. I'll look that up this evening, BUT any billet that has been folded 2000 times wouldn't have any material of any kind left in it long before 2000 folds were reached! Perhaps there may have been some confusion and what was meant was 2000 layers instead?
 
Thanks, Guy, that helps a lot. Am I still right that folding 2000 times is out of the question?

- Chris
 
That occured to me,too, but the way he was talking about it, it deffinately seemed like he meant 2000 folds. What he said was that on japanese swords, they engrave a chrysanthimum into the base of the blade if it had been folded 1000 times, and that this sword of his had two. 1000 layers does't seem like such a big deal - just 10 folds. Even if it is a big deal, going to 2000 layers is just one more fold so I can't immagine a big deal being made over 2000 layers vs 1000 layers. I think engraving that extra flower would probably take more time than folding it one more time. Either way, I'm pretty certain that this sword the dude was describing exists only as a figment of his immagination. The sword came towards the end of a rather long line of crap that had been comming out of his mouth to which I had just been smiling and nodding. It really wasn't worth arguing with him. You know the type.
Thanks again for the info.

- Chris
 
There are some other things to consider also Chris. One is when folded steel was popular. As Guy pointed out, much of the belief is because of the old Masters. They did it because it was a way to control the properties of the blade with the equipment and knowledge they had at the time.

The idea of the laminated steel is like two pieces of wood with a razor blade in the middle. The center could be very hard and the shell protected it and minimized chipping. Worked then and works now.

Now here's where I might take some heat. IMHO and only IMHO, a folded blade and a laminated blade and a blade made from modern steel, all made by smiths that are good with that type of construction, will be equal.

Much of this is due to the advent of modern heat treating equipment and improvement of steel. Laminated sounds good and I freely admit that pattern welded steel is beautiful, but.....preformance wise, there will be no difference.
 
fold the blade 2,000 plus times and then buy that iron wood log on ebay for
2 grand and make knifes.
 
peter nap said:
Now here's where I might take some heat. IMHO and only IMHO, a folded blade and a laminated blade and a blade made from modern steel, all made by smiths that are good with that type of construction, will be equal.

Much of this is due to the advent of modern heat treating equipment and improvement of steel. Laminated sounds good and I freely admit that pattern welded steel is beautiful, but.....preformance wise, there will be no difference.
Click to expand...
Don: Are you asking for heat or what??? :confused: I am not saying a word. For a change. :rolleyes:
 
The chrysanthimum (unsure of spelling so I used yours) is not the mark to indicate the number of folds, but was a japanese armories mark, and can be found on a lot of things from the ww2 era, including a rifle I have in my collection.

Forget I said that;

Maybe your friend would like to buy my rifle, the barrel has been folded 1000 times :) I believe the stock is made of ironwood as well, I'll sacrifice it for a mere $200,000, jeez, thats not even a dime a layer!

Tony
 
Actualy with todays steels, if everything is done right your likely to get a little higher performance out of mono steel than a laminated or folded steel simply because of the high heat required to weld grows large grain. The way I understand the Japanese smiths were well known for welding at low temps, and I asume that was because high temps grow grain, larg grain equals poor performance, and normilizing can only go so far.

The sanmai or laminated may have slightly more edge holding potential in certain combinations, but in all practicality would anyone notice a few more cuts one way or the other in the real world?

Also many of the Japanese sword blades were both composit construction along with being folded. Many had a higher carbon jacket welded around a lower carbon core, and some had a low carbon core, high carbon edge, and medium carbon sides. The layering on some of the swords could be upwards of a million layers, but that was as stated to even out the carbon and work out impurities of the steel. The basic sword steel was basicly carbon and iron, no other alloys were added.
 
Will52100 said:
Actualy with todays steels, if everything is done right your likely to get a little higher performance out of mono steel than a laminated or folded steel simply because of the high heat required to weld grows large grain. The way I understand the Japanese smiths were well known for welding at low temps, and I asume that was because high temps grow grain, larg grain equals poor performance, and normilizing can only go so far.
Click to expand...

I think I disagree with the last bit of your post there Will (nothing personal! ;)). Welding heats in my opinion, while excessive, by no means take the grain of a steel beyond the point that proper mormalizing or thermal cycling won't cure. But you've brought up an interesting point, I have no idea whether Japanese smiths practice normalizing, but when forging a blade blank they do use increasingly cooler heats for the finishing operations which equates to normalizing or thermal cycling.
 
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