carbide banding

In the Oct. 06 issue of Blade Magazine, Ed Fowler has an article entitled "The Benefits of Sharing". While the jist of the article is
about the downside of trade secrets there is a bit about the testing of a blade which exhibits radically different force when flexing the blade 90 degrees from one side to the other. When etched the sides showed different amounts of carbide banding. Appearently the carbide banding is what gave wootz its legendary toughness. Since the carbides disolve when steel is austentized befor quenching to form martinsite the beneficial effects of the carbide banding is lost on a traditional heat treat. This leads me to think that if you could develop the carbide banding and protect that banding on the spine (perhaps by clay-coating) you would create a blade with a good cutting edge and some of the toughness of wootz.
What are your thoughts on this?
And how can carbide banding be created (I'm mostly interested in 1095 as that is what I'm working with right now)?
ron
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hi Ron,
The carbide banding is a natural addition of carbon provided by charcoal or coal.
Wootz was a crucible steel, created from pouring pure iron into an ingot mould or just a bloom blob. The action of forging the iron into square bars introduces carbon (as discussed before), and twisting these bars to form the twist pattern adds more carbon.
Carbon plus iron = steel.
If you want to replicate wootz you can't really achieve it with a gas forge, as the same carbonised environment isn't reproduced with gas.
Traditionally the smiths used to have a core of wootz and a high carbon steel edge. Wootz wasn't used as an edge.
What we do today is similar, we make a damascus core, and forge weld a high carbon steel edge, this is for working blades that you want to be pretty.
If the blade isn't intended for extreme use than a full damascus blade is nice.
1095, haven't used it myself, but you could try a nasty charcoal/coal forge, make a square bar, and twist it, then hammer it square again. Polish it up smooth, then dump it in an acid bath, 25 hours for vinegar or 25 minutes for ferric chloride. Make sure if you use ferric chloride that you neurtalise the acid with bicarb-soda and water. Rinse thoroughly. I think this would make a good test to see if you can replicate the banding with this alloy.
Regards Charles
r payne wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Chilla wrote:

I'm not necessarily looking to reproduce wootz. I'm interested in the carbide banding as is seen in wootz. As I understand what was in the article, the carbide banding was responsible for the toughness seen in wootz.

I run charcoal and don't find it nasty at all. I rather like it.
ron
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Oh okay. Well I suppose the iron would make the blade flex, while the steel (the carbon banding) would add the strength. We're not talking about the best steel in the world (depending on what you consider to be the best steel in the world).
Okay let's see what would be the easiest way for you to replicate the banding. You could get a length of high carbon steel, and a length of mild steel (steer clear of free metal as this wont work).
Make two square section bars (if you're using charcoal they might have to be thin to get to welding temperature, forge weld the two bars, and make into one square section bar square. If the welding is good you could do this next step cold, however if you can get a uniform heat along the length of bar the twist will remain even and will be a little easier to do. Twist the bar along it's length 2 - 3 twists per inch. Forge square again, to see the pattern dump in acid.
As you are using a charcoal forge the mild steel will pick up a little extra carbon.
These days wootz isn't necessary, as we can pick the steel we use by examining it's chemical properties. An example a high maganese steel will work harden and become extremely tough and would be great for an edge, examining the chemical components of metal shouldn't be under-rated. Steer clear of high phosperous or high sulphur content in steels that you want to forge.
I used to run a little charcoal wooden box forge (based on an ancient design), and after using it I felt like I'd puffed a packet of ciggies. The nastier the better for a charcoal forge, it adds more carbon into the work.
Regards Charles
r payne wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Chilla wrote:

There's a fellow down in Fla. named Al Pendray who has done some comprehensive work on reproduction of 'wootz'. He's had several write-ups in both "Blade" and "Knives Illistrated" magazines. IIRC, it involves a crucible melt and a very slow cooling (several hours) at precicely controlled temps to control the 'freezing' and crystaline growth in the melt. The exact temps were never published, but Al alledged that he was getting very close to nailing the heat cycle down, having a roughly 50% success rate in the finished 'puck' at the bottom of the crucible. This was about ten years back. You might want to Google the back issues and see what you can come up with. BTW, Al used gas and a sealed crucible with a pyrometer in the crucible. Said it gave a better control on the temps.
Charly
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Chilla wrote:

There was an article in a 1983? Scientific American about some guys who stumbled across _a_ way to make good wootz (I have it around here somewhere, the article that is).
They used an ultra high carbon steel (~1.9%) and gave it a ~15 hour soak at a fairly high temp to allow the carbide to precipitate out, then worked it at low forging temps to break that lattice up. They ended up with fairly pure iron with little granules of iron carbide spread throughout.
When they deformed the metal by at least 8:1 the microphotographs of the results were nearly identical to historical samples. The 'watered' pattern comes up in the steel naturally, no twisting necessary.
- Carl
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Carl wrote:

http://www.mines.edu/Academic/met/pe/faculty/eberhart/classes/down_loads/damascus.pdf
Heres the link to the SciAm article. Scroll to the bottom to see pics of Mr Pendray in action.
Cheers Trevor Jones
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I like that thanks very much :-) Regards Charles
Trevor Jones wrote:

http://www.mines.edu/Academic/met/pe/faculty/eberhart/classes/down_loads/damascus.pdf

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.