Very interesting reading on Japanese steel and layered steel (damascus).

[nozh2002]

I found this explanation of steel from Japanese sword expert:

http://www.ksky.ne.jp/~sumie99/steel.html

Interesting point - "damascus" pattern is just a side effect of long purifying process of tamahogane. Pattern itself make no sense until it is appear on blade made traditional way out of piece of tamahagane.

Same for hamon - it is sign of fine-grain steel and make no sense as well if it is not on nihhonto made out of tamahagane.

I enjoy browsing this site - gallery especially. I laerned that ther are Japanese swords with edge on both sides etc.

Thanks, Vassili.

 

[akadave2]

It is facinating the process they go through to create steel to make swords (Nihonto). From iron sand to a blob of what looks like slag. They folded the steel to make it more homogeneous (spread the carbon throughout the steel). They didnt have the technology to completely smelt steel apparently.

There are actually 1100 terms used with Nihonto. Quite a bit of them are used to describe the "activity" and grain (hada) in the steel. Itame or Wood grain hada is the most common. They used a concoction of iron oxide and other elements called Nugui to bring out the activity in the blade. Not an etch more of a burnish to bring out the difference in the steel folds and hamon. The hada even on a freshly polished blade is much more subtle than damascus. Also the crystalized formations in the hamon are incredibly complex and purposely created in some masterpieces.

Even though the hamon is easily seen on a freshly polished blade, the hamon is often gone over with Jizuya finger stones to whiten the hamon. Not all smiths whitened as much as others...it was whatever was in style.

Anyway...I talk too much.

 

[nozh2002]

I think this is most educational part:

"On the modern steels.
There are various kinds of steels that are specially made for each usage. A modern steel for edge tools is already contained many metals to get the best utility to the target. The modern technology can make steels like a mix metal juice by controlling all the metal contents, and formed into various sizes of bars or plates. Of course, the steel never includes slag nor bubbles. You can choose the best one out of various kinds of steels, and instantly forge it to blades or other tools. Modern steels are already completed special alloys.
If you take fold welding onto such modern steels, the heating work doesn't effect the content of the metals. Only carbon content can be down. I am afraid if the best balance of contains are broken by the work. And the fold welding work can put the oxidized iron among the layers of steel.
In conclusion, the fold welding work onto the modern steels can get down the steel quality, rather than "no effect". "

Thanks, Vassili.

 

[adamlau]

So if anything, a Damascus blade is potentially less durable with potentially less edge retention than a similar blade of an alloy of known properties.

 

[akadave2]

As with the the evolution of any technology. The ability to create a totally homogeneous steel rather than fold differing layers of steel with different carbon content to achieve an approximation gives you a better product for a cutting tool. Also the ability to alloy other metals into steel to enhance their toughness and durability is key as well.

The Japanese tried to accomodate the nature of the steel they used by affecting the grain of the steel near the cutting edge so that when and if it chipped, the blade would not be ruined and could be repaired. They also used multi-piece conctruction, sometimes up to 5 piece blades. Its interesting to note that the Mune, or top of the blade is made almost dead soft. If blade to blade contact was to occur, the swordsmen were trained to parry on the mune which would of course save the cutting edge and cause the other blade to stick and not slide along the blade.

I think that todays damascus can be very durable and sharp indeed. After all they are using modern steels now

 

[nozh2002]

So if anything, a Damascus blade is potentially less durable with potentially less edge retention than a similar blade of an alloy of known properties.

It is well known fact that only skilled smith can produce damascus which will be not too much worse then steels it produced from. Damascus gives you pattern which some people like but for expense of quality.

Thanks, Vassili.