Carbon migration - anything to worry about?

weo

weo

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Sep 21, 2014
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Hello all. I was forging up a few Damascus blanks yesterday with my friend who introduced me to the blacksmithing world ~6 years ago (he's been doing it for 40+years). As I'm relatively new to the craft (and very new to the pattern welded world), I'm not as confident in my visual judging of welding temps as I'd like to be yet, so I tend to let the billets soak for a few minutes to make sure they are at welding temp all the way through. Terry said I shouldn't do this as I'm risking carbon migration. (I'll add that he's been smithing for 40+years, but I seem to have gotten him into Damascus and knifemaking:cool:.)
Now, I know this is a real phenomenon under the right circumstances, but is it something I should worry about? Forging mainly 1084/15N20, 1095/15N20, O1 and 5160. Also, total time the billets are in the forge is about 15 minutes (just a guess) taking 3 welding heats.
Thanks
~billyO
 
You don't say what your final layer count (target) is...
Carbon diffusion will occur at welding/forging heat and will likely
be even throughout the billet by he time you get the layer count up
high enough to give you a decent looking blade.....

Soaking for a few minutes at welding heat to make sure the billet is
up to heat all the way through, is a good practice....
 
Thanks for the response, Russ.
Being a new maker, I'm still playing around with different layer counts, but my billets to date have been between 120-400ish layers.
 
Thanks, Don. That was my understanding through my reading.
On a related note, is there too long of a soak for reasons other than a waste of time and fuel?
Thanks again
~billyO
 
If you soak too long and your forge environment is oxidizing, you'll start building scale where you don't want it. I think that's been my problem with making damascus to this point. I haven't really tuned my forge to run rich enough to prevent it.
 
It's really diffusion not migration. LOL In any case normally you will get diffusion but it's not a problem. Of your mixes 1084/15N20 is the best . A fine users blade ,responds to etching well and what many don't consider is that the two steels have similar HT procedures .No compromise for HT.
 
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