|
Post by Matt993f.o.d on Jan 23, 2008 20:40:27 GMT
Don't worry, this isnt another "this steel is BETTER than that one" thread. I am just wondering, since I don't know too much about Tamahagane, what the whole fuss is about.
To me, metallurgically under educated, it sounds like a pretty poor way of steel making, to be honest. Sites selling Tamahagane Kats claim that the iron sand used to make the steel is "very pure" but that sounds like marketing tosh. To me, Tamahagane production sounds much like Ye Olde way of smelting iron in a bloomery, except slightly different (as in, they use a tahara instead of a european bloomery). The products are the same, you get a small amount of cast iron (melted run off), a 'bloom' of wrought iron (that they presumably don't use), and a small amount of carbon steel, which is the stuff they use for sword making.
It basically sounds to me like old fashioned steel, of random quality.
Is there a real metallurgical advantage to Tamahagane, or is it just a traditional technique that has turned into a marketing gimmick to make some swords more expensive?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jan 23, 2008 20:57:02 GMT
I'm slightly biased, but I would be leaning towards the second reason. In Japanese sword circles, tradition is held in very high regard, so using a technique that's hundreds and hundreds of years old gives you mega points in that regard. The way I see it is this. The Japanese originally didn't have ore that could produce high quality iron through normal methods. So, they had to come up with this elaborate way to smelt the iron, which even then wasn't of as high a quality of steels from say, Europe. So, in order to make a billet of steel that was any good, they had to fold if to remove the impurities. That's what constitutes Tamahagane. So, any benefits of the steel are all intangible. Since Japanese sword making is hyper-spiritual, (Imbueing the blade with the soul of the smith, the soul of the warrior, etc.) the steel manufacturing process is the same way. It's basically a vert traditional technique to produce a small amount of high-carbon steel that may or may no be as good as modern steels. That's basically it, as far as I see it. If anyone has evidence to the contrary, I'd love to hear it, since I'm not a metallurgist. Hope that answers your question!
|
|
|
Post by Dan Davis on Jan 23, 2008 21:35:30 GMT
fellows, the tatara smelter method is essentially the same process as an iron bloomery except that they combine the iron blooming process and the steel cementation process into one operation. In that respect most if not all of the bloom from a tatara is steel in various grades and hardnesses.
There is no real, valid reason to use tamahagane other than the appearance factor but there IS a very definite visual difference between tamahagane and laminated modern steels.
As far as quality goes, that depends on the smith manipulating the steel but in reality steel is steel no matter how you come by it. If you could not look at tamahagane and see a difference then there is no way you could tell the difference between a blade made from it and any other steel.
|
|
|
Post by Matt993f.o.d on Jan 24, 2008 11:17:56 GMT
So it looks different?! How odd!
|
|
|
Post by themaster293 on Jan 25, 2008 6:29:11 GMT
Yeah that is.
|
|
slav
Member
Senior Forumite
Katsujin No Ken
Posts: 4,457
|
Post by slav on Jan 25, 2008 7:52:20 GMT
Yes, of course it looks different. Look at the "hada" on a Nihonto blade, and look at a modern Laminated blade...
It's hard to explain, but you'll see the difference.
Among other attributes, Tamahagane takes on a sort of "dusty" look, almost like there are microscopic specs of debris all over the blade. This is because the makeup of Tamahagane is never perfectly even, and each layer is heterogenous.
Modern steel is very consistent in makeup, so if folded it barely takes on hada at all; unless two different steels are alternately used during lamination, which yields a look very different from tamahagane, and more like very high layer-count damascus.
Walter Sorrells sometimes uses what he calls "Canahagane", which is supposed to mimic the look of Tamahagane. It consists of powdered 1084 and ground up cast iron, plus some other things.
|
|
|
Post by Matt993f.o.d on Jan 25, 2008 8:59:34 GMT
I thought you couldnt use cast iron in a forge at all...
Or does he do something else first?
|
|
|
Post by Dan Davis on Jan 25, 2008 14:23:27 GMT
"cast iron" is really just very high carbon-content steel; on the order of 3% or greater. It is workable in a forge but you have to be very careful and in a blade-making situation it would be a material you would WANT to decarburize.
|
|
|
Post by Matt993f.o.d on Jan 25, 2008 15:29:39 GMT
I wondered if that was the case. I have a book I am reading on smithing (The art of Blacksmithing, Alex Bealer), and in the section on metal he writes that cast iron is iron with a carbon content of around 3% (like you have just said). He refers to it exclusively as iron though, which is probably why I got confused.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jan 26, 2008 4:49:55 GMT
The real wonder about tamahagane is the fact that the smiths take and make it from SAND into a useable blade!
|
|
|
Post by Matt993f.o.d on Jan 27, 2008 19:41:42 GMT
Isnt the iron sand they use essentially similar to bog iron...
|
|
|
Post by Dan Davis on Jan 28, 2008 0:59:50 GMT
not at all; it is more akin to black hematite sandblasting media.
|
|
|
Post by Matt993f.o.d on Jan 28, 2008 12:49:53 GMT
Ha. Thats cool. I have a massive great sack of that in the shed.
|
|
|
Post by jw on Feb 26, 2008 0:54:18 GMT
Back in the day, when you couldn't go ad buy metal in a multitude of carbon contents and with various other elements thrown in for good measure and special properties, if one needed to forge a sword where would one go?!?!? Your lost on a Pacific island and you need to make metal, how do you do it? Now you understand Tamahagane... ;D As far as tradition goes in Japan, now you understand why they still use it... ;D Think of this too, a sword from stone, hematite is rock from lava, black sand is little hematite rocks that contain ferrous oxide, which when condensed and manipulated gives you steel... It's a full circle, from rust to steel to rust...
|
|
|
Post by salvatore on Feb 26, 2008 2:05:20 GMT
The iron the Japanese were said to have used was bad stuff. Pig iron, with a shockingly high carbon content(About 3.5 some say, that is high!), was smelted in a tatara, which is a furnace. When you smelt, a lot of carbon is lost, that is why the sand is added. After that, the material is(Forgot to add that the fire has been looked over for 3 days and nights) extracted, looked over by a "Master smith", some pieces are rejected, only good for knives,but not for a good sword.
The sword is folded, laminated, clayed, fired again,quenched.
The clay mixture was that of charcoal and clay, applied to blade. Prior, when smithing, steel is wrapped in paper, ashes and clay to reduce oxydation.
It is then sent off to a polisher, polished,sharpened, blah blah. ;D
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 26, 2008 12:49:40 GMT
But what is the "Swedish powdered steel" then? I thought that was like the iron sand the Japanese use O,o.
|
|
|
Post by salvatore on Feb 27, 2008 5:08:19 GMT
Swedish powder steel. It is a bit obscure, there are multiple forms of swedish powder steel. There has been a lawsuit actually, Japan filed a lawsuit against Sweden, because they say the steel has been used by them first, and it was there doing that made it.
If you are refering to bugei blades, I am not sure if you will find out.
|
|
|
Post by Matt993f.o.d on Feb 27, 2008 11:35:18 GMT
Ha! That's a bit silly. Trying to sue over an iron smelting technique probably many hundreds of years old. Surely any copyrights they have would be out of date on some grandfather clause or other by now?
|
|
|
Post by Dan Davis on Feb 27, 2008 13:03:21 GMT
Swedish Powdered Steel process is not old at all; it was developed in the 1970's.
It is a process where raw iron, manganese, carbon and other dopants are powdered into dust. These powders are then combined, mixed very well, and compressed into a hydraulic mold. The mold is vacuumed out and heated to approximately 2900F, then stamped in a hydraulic press to fuse the metal and other elements together.
Do not confuse the Korean metallurgical rating system (SPS10, for instance) with a designation indicating Swedish Powdered Steel because it is not and do not equate Swedish Powdered steel with tamahagane because of the hada in a Hanwei sword; the hada is there because the smiths at Hanwei fold and laminate the steel once they get it.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 27, 2008 15:53:43 GMT
Well I've never heard about that Korean stuff but many websites that sell shinken or really expensive iaitos say that they use Swedish powdered steel so thanks for the info.
|
|