- Joined
- Aug 1, 1999
- Messages
- 3,036
Here I am skating further out on the pond, knowing the ice is pretty thin... 
I think one or two modern steels compare favorably with the best of the traditionally made steels of medieval craftsmanship. It is certainly more uniform, with each batch produced in exactly the same, quality controlled procedure as previous batches, with QC testing performed in process to insure no errors in formulation or procedure, and it is made from raw materials that are themselves more rigorously controlled than the river sand or ore pits of ancient times. If you think about it, modern steel companies are certainly capable of analyzing and reproducing pretty much any steel formulation of the past - even wootz if the demand were high enough to warrant it. I guess the question then really is can blades ground from modern batch-produced steels compare with the hand forged steels of any period, but particularly the classic periods of Japanese or European sword making?
I think so, and here's why based on my personal understanding (or lack thereof) of the comparative attributes. Some of this is an educated guess, since some of the materials in question have never been measured by modern testing methods.
The traditional Japanese sword is comprised of layered steel with a differential temper. The layering achieves a quasi-Damascus effect where the layers interrupt any stress risers that might otherwise expand and cause the blade to fracture with lateral stress. The blade is further protected from catastrophic fracture by having only the edge fully hardened with the spine at some hardness below that, allowing it to retain more of a spring temper, but not hard enough to be brittle. The hardened edge is protected from fracturing by the softer spine behind it. In fact the edge might fracture locally, but the blade would continue to be serviceable. I'm not sure what the hardness numbers are for the edge and spine of a typical katana, but for arguments sake let's say Rc60 for the edge and Rc 45-50 for the spine. We know that katanas did in fact break, but in more instances they would bend and retain a set. There is no question that the steel was fine grained, the result of the very long forging process practiced by Japanese craftsmen. Fine grain is in itself a major reason why the steel is tough, and by that I mean tough throughout, including the edge, not just in the low temper areas.
Modern steels produced by standard crucible melt processing can not achieve the fine grain structure of well forged steel. Some probably get pretty close, but they can still be improved with forging. That's what forging does. Some say that forging also packs the steel more tightly on the edge; I'm not sure how you prove that. Then again, maybe having a finer grain means that it is "packed more tightly". I simply don't know, but I doubt you significantly increase the density of a homogenous steel by hammering it. You more likely achieve some level of grain orientation that is useful in keeping a blade intact.
However, powder metallurgy used in steel manufacture can achieve very fine grain structures, and in the case of Crucible Steel's CPM's ultra fine particle metallurgy, extremely fine grained steels can be achieved. You don't have to work with high alloy steels a lot to see what powder metallurgy can do. RWL-34 (made by Damasteel in Sweden) which is exactly the same formula as ATS34, but with 0.2% Vanadium added, is dramatically more fine grained than the best batch of ATS-34 ever produced. It takes a polish that is almost hard to imagine. No matter what you do, you can't get the same level of polish on ATS-34. RWL-34 also will outwear ATS-34 and is noticeably tougher. It makes great blades and I wish it were more readily available.
Now here's where I'll get controversial, so I'll break it here and start another post to continue.
I think one or two modern steels compare favorably with the best of the traditionally made steels of medieval craftsmanship. It is certainly more uniform, with each batch produced in exactly the same, quality controlled procedure as previous batches, with QC testing performed in process to insure no errors in formulation or procedure, and it is made from raw materials that are themselves more rigorously controlled than the river sand or ore pits of ancient times. If you think about it, modern steel companies are certainly capable of analyzing and reproducing pretty much any steel formulation of the past - even wootz if the demand were high enough to warrant it. I guess the question then really is can blades ground from modern batch-produced steels compare with the hand forged steels of any period, but particularly the classic periods of Japanese or European sword making?
I think so, and here's why based on my personal understanding (or lack thereof) of the comparative attributes. Some of this is an educated guess, since some of the materials in question have never been measured by modern testing methods.
The traditional Japanese sword is comprised of layered steel with a differential temper. The layering achieves a quasi-Damascus effect where the layers interrupt any stress risers that might otherwise expand and cause the blade to fracture with lateral stress. The blade is further protected from catastrophic fracture by having only the edge fully hardened with the spine at some hardness below that, allowing it to retain more of a spring temper, but not hard enough to be brittle. The hardened edge is protected from fracturing by the softer spine behind it. In fact the edge might fracture locally, but the blade would continue to be serviceable. I'm not sure what the hardness numbers are for the edge and spine of a typical katana, but for arguments sake let's say Rc60 for the edge and Rc 45-50 for the spine. We know that katanas did in fact break, but in more instances they would bend and retain a set. There is no question that the steel was fine grained, the result of the very long forging process practiced by Japanese craftsmen. Fine grain is in itself a major reason why the steel is tough, and by that I mean tough throughout, including the edge, not just in the low temper areas.
Modern steels produced by standard crucible melt processing can not achieve the fine grain structure of well forged steel. Some probably get pretty close, but they can still be improved with forging. That's what forging does. Some say that forging also packs the steel more tightly on the edge; I'm not sure how you prove that. Then again, maybe having a finer grain means that it is "packed more tightly". I simply don't know, but I doubt you significantly increase the density of a homogenous steel by hammering it. You more likely achieve some level of grain orientation that is useful in keeping a blade intact.
However, powder metallurgy used in steel manufacture can achieve very fine grain structures, and in the case of Crucible Steel's CPM's ultra fine particle metallurgy, extremely fine grained steels can be achieved. You don't have to work with high alloy steels a lot to see what powder metallurgy can do. RWL-34 (made by Damasteel in Sweden) which is exactly the same formula as ATS34, but with 0.2% Vanadium added, is dramatically more fine grained than the best batch of ATS-34 ever produced. It takes a polish that is almost hard to imagine. No matter what you do, you can't get the same level of polish on ATS-34. RWL-34 also will outwear ATS-34 and is noticeably tougher. It makes great blades and I wish it were more readily available.
Now here's where I'll get controversial, so I'll break it here and start another post to continue.