three steel damascus

[Ed Caffrey]

Dead Ringer Bill! I agree.

[GHEzell]

Originally Posted by Riley White

I have been thinking about a way to make a very tough knife (I know all Damascus is tough) with a core that would give the knife a very strong edge holding capability. This is what I propose to do. The main part of the knife would be 1095/L6 while the core would be 52100. After I hammer the 1095/L6 out into 160 layers I would part it one last time and put a layer of 52100 in the middle and weld it. I chose 52100 for the core because of the reputation it has for edge holding. The others could also be 5160/L6 instead of 1095/L6. What do you think?

I've been thinking the same thing myself. My idea is to have 1% carbon in the edge steel, with only about .6% in the body. Now here's the kicker: I plan to harden the entire blade, not just an edge quench like I normally do. The theory is, once tempered the edge will be nice and hard, around 58 rockwell, while the body, tempered at the same temp, should be around 48 to 50....springy, with a good hard edge. I hope to try this on a test piece as soon as I can, because I think it may have some interesting properties.

Carbon migration will have to be kept at a minimum for it to work the way I want it to... The steels will need to be compatable, my first attempt with a 1095 edge, 5160/L6 body refused to stay together, I suspect due to mixing a shallow hardening steel with a deep hardening one...the test blade came apart during hardening, but showed no problems and tight welds beforehand.

Anyway, good luck and let us know how it turns out.

[schwarzer]

There is a lot of good information in all of these replys. i have been using a 52100 mix for my center core blades for over twenty years. It is pretty tough to over heat . But any damage done can be repaired by thermo cycling unless you burn the steel in the forge welding stage. Carbon migration goes very slow except in very fine layering. The finer the layers the faster it moves. Unless it is impeaded by nickle alloy. Case hardning take a long time to penetrate just a few thousands because the receving material has so much volume. Pendray and I ran into this anomoly years ago . The carbon moved very slow when we first started layering material. As the layers became fine the process speeded up on a geometric progression. I presented papers on carbon difusion in 1993 at the international comference on damascus steel in Germany on behalf of Dr John Verhoven I will try to dig them out I have forgotten most of the information as to time and temperature In different alloys. Some japanese blades have a soft core The construction allows for a very quick initial weld and a some what cooler forging temp to keep the core soft.
Sperodized 52100 is very difficult to get hardned properly . The best solution is to grow the grain fairly hot putting the carbon back into solution and then thermo cycling the grain back down to fine.
You see alot of blue knives
\52100 works great tempered at these temperature because it cut very well in the low 50,s rockwell C Other carbon steels do not retain toughness at this low hardness

[raker]

Glad to see you again, Steve
The papers on carbon diffusion would be a very interesting read for me. If it were possible, would you bring them to the Blade Show?