Carbon migration?

Tom Lewis

Tom Lewis

Joined
Feb 24, 2000
Messages
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I have used the search engine and found nothing on carbon migration.
Lets say I make a san mai billet of two pieces of mild steel sandwiched around a piece of high carbon steel. I then forge weld the three pieces together. Maybe I draw it out cut in three pieces, stack and re-weld.
How long would it take before all three pieces had the same carbon content? Would carbon migration work like this?
I especially hope Larrin will give his thoughts on this.
 
I got some cool gradation with this. It was stainless sides and a W2 core.

Photo%20May%2005%2C%205%2054%2010%20PM.jpg
 
Here's a quote from an article I downloaded a number of years ago (I'll see if I can find the link):

METALLOGRAPHY OF A MODERN PATTERN-WELDED STEEL KNIFE BLADE by Thomas Nizolek Lehigh University Bethlehem, Pennsylvania in ADVANCED MATERIALS & PROCESSES/FEBRUARY 2009
"For this investigation, a bar of pattern-welded steel was created from W-2 tool steel and ASME AS-203E pressure vessel steel using traditional bladesmithing methods. Samples were removed after each step of manufacture, yielding samples having 4, 8, 16, 32, 64, 128, and 256 layers. . . Due to the dissimilar chemical composition of the steels metallurgically bonded together and then forged, diffusion between the layers was expected. The W-2 is a high carbon steel (1.07 wt.% carbon) while the 203E is a low carbon steel (0.14 wt.% carbon) with 3.45 wt.% nickel . . . ...The forged samples (shown in cross section, Fig. 4 to 10) were annealed; therefore, the extent of carbon diffusion can be visually determined by the distribution of pearlite. In the four layer sample (Fig. 4 and 5) it is evident, based on the pearlite gradient between the two layers, that extensive carbon diffusion occurred after the first step in manufacture. In the eight-layer sample it is observed that the pearlite concentration has almost equalized, however ferrite still decorates the prior-austenitic grain boundaries in the 203E layer (Fig. 6). By the time the material has reached 16 layers, the carbon content of the sample appears to be uniform as shown by both layers consisting of nearly 100% pearlite (Fig. 7 and 8)."

So it looks like 3 folds will get there. Not sure how many heats for each fold, though.
 
Thanks, Larrin and Weo, that was the information I was looking for. I think carbon migration is another reason not to try to take the can off of canister damascus.
 
Carbon will migrate in mild steel can to , so thin can as it was possible is good idea ? I wonder how much carbon will have final damascus , i mean how much carbon will pull mild steel can ?
 
I should add to my post, that in re-reading the full article, there is no mention of how thick the individual starting stock is, and I would think that would be a determining factor. So I should modify my previous reply
weo said:
So it looks like 3 folds will get there
Click to expand...
to: So it looks like 3 folds or more, or less, should get there. ;)
 
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