"alloy" or "carbide" banding

D

dustfurn

Joined
Oct 2, 2007
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I am interested in how one would go about inducing the phenomena people call "alloy banding"? Say, in a high-carbon steel like 1095, O1 or W1 (would the procedure differ significantly for each of these steels?)

I would think it would be something like:

-Full sphereodize anneal
-Get up to critical (probably on the low side of critical?) and quench immediately (minimal soak time)

Does that sound about right?

Thanks,
Dustin
 
There was a big hoopla a few years back where a maker had patented a method to produce alloy banding in knife steel. Another maker happened to accidentally produce similar banding effects through entirely different methods and the patent holder threatened a ridiculous lawsuit. I believe he was affectionately referred to as "a$shat" around the forums. :)

As to how to acheive purposeful banding, I'm not entirely sure. I've had the effect appear in a freshly quenched blade in the past, but have no idea how to replicate the effect or if I'd even want to replicate it. I'll see if I can find the picture and post it later on tonight.

--nathan
 
I believe you have to somewhat overheat the steel. take it alittle past critical maybe 1 to 2 hundred over critical but below welding and quench, that way the carbides are just starting to get into solution, but dont get fully dissolved. I've gotten a few peices of PFG O1 that once etched showed banding. PRIOR to being heat treated.
 
Here's a piece of O-1 straight out of quench. I wish I had etched it once it was finished. Interesting pattern that was suggested to be alloy banding by others on the board.

IMG_3675.jpg


--nathan
 
This really isn't a;; that good for your steel. Sure, it makes a pretty neat pattern, but segregating your steel like that can produce some inconsistant results in performance. Not something I would want my name on, as you can't control how it's going to behave.
 
Silver Pilate, that photo isn't alloy banding. Banding would show up as parallel lines ,not lines in random direction.. Metallurgists hate banding. Yes it can reduce properties.If you want stripes make damascus !!
 
mete said:
Silver Pilate, that photo isn't alloy banding. Banding would show up as parallel lines ,not lines in random direction.. Metallurgists hate banding. Yes it can reduce properties.If you want stripes make damascus !!
Click to expand...

Thanks for the replies so far. Not trying to be *too* snarky, but...i'm not a metallurgist! ;)

Let's just say, for the sake of arguing, that I just want the knowledge of how to accomplish this...maybe I will make a blade using this technique, maybe I won't, however, I acknowledge and fully understand that this probably *will not* result in the optimal heat-treatment of the steel!

Thanks again,
Dustin
 
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I was going to say that either Kevin or Mete would jump inot this thread and beat you down!!! lol. Alloy banding is hit or miss as far as looks go and according to folks a lot more experience than me, defeats the purpose of having all of those nice alloying elements in your steel.
 
I don't know if you'd call it alloy banding, but I get something like a faint wootze look with high alloy carbon steels like 52100 and 5160. Lots of low temp thermal cycles and multiple quenches and never over heat and I get it every time. It takes an etch to bring it out and again, it's faint, nothing so prononced as real wootze or damascus, but in the light you can see it and I get it every time. Funy thing is the blades I've done this way out performed the ones I didn't get the pattern. Granted it's not much of a differance and the end usser would probably never notice, but it looks good and performs well.
 
Silver Pilate, I think those patterns are surface effects form not removing enough of decarb ,grinding marks etc.
There is a post by Kevin Cashen somewhere that explains how to do it but I don't remember.After all metallurgists have tried very hard to eliminate the condition !!!
 
I always thought that there were two kinds of carbide banding (not sure about alloy banding though). A coarse banding that was made by overheating the metal that usually included grain growth and completely messes up your steel. Then there's fine banding which looks like high layer (800+layer) damascus/laminated steel, and that the fine banding was fainter, yet improved the cutting performance and durability of the knife since the banding was caused by carbides lining themselves up in the direction the knife was forged. That and, since fine carbide banding is caused by short soak times at lower heats, the grain in fine banded steel is also very fine, creating a good quality knife blade. I was under the impression that fine carbide banding was less known simply because it was harder to see this effect in most steels. Does this make sense to anyone else? I'm just trying to put together the pieces of what I've heard of fine vs coarse banding from other, more knowledgable bladesmiths.
 
The makers of wootz steel use this phenomenon to create the wootz pattern today.
The steel is mixed in carbon and alloy content and melted. The mix is often near cast iron in carbon content and has a variety of alloy ingredients to be the carbide formers. Along the way to becoming a knife the steel is heated and held at specific temperatures, for specific ( long) times, and as the cycles are repeated ( dozens of times to hundreds of times) the carbides form dendrites ( bands) and make the original damascus pattern we call wootz.
Slowly the bloom is worked into a billet, and finally a blade blank. There are many places where the process can go wrong.
 
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