forge scale

T

tmr

Well-Known Member
Hey guys......I just finished forging 3 billets of layer damascus from 24 in circular saw blade material <L6?> and 15n20.......everything welded up fine but I ended up with extremely hard forge scale on the surface of the billets.......I am wondering what is causing this as I was fluxing entire billet during weld....this is the first time that I have tried the circular saw blade in damascus but i have forged it into knives by itself and not had a scale problem.......any thoughts of why this is happening ????
 
That saw blade is very likely NOT L6..... more likely it's "mystery steel". Nickel is most likely the culprit. Anything that contains nickel (15N20 does, and if the saw blade is indeed L6....so does it), will cause huge amounts of scale.... this is because nickel oxidizes so readily. The other issue could be how your forge is burning/tuned. If you have even a slight overage of air in your fuel/air mix, scale will be excessive.
 
Flux + iron oxide will always be a bit thicker and tougher than just iron oxide, but an overnight soak in sodium bisulfate, or a good strong vinegar, will allow you to just brush that scale off.
 
Kevin R. Cashen said:
Flux + iron oxide will always be a bit thicker and tougher than just iron oxide, but an overnight soak in sodium bisulfate, or a good strong vinegar, will allow you to just brush that scale off.
Click to expand...
I bought a jug of sulfuric acid from Napa and have it in a bucket that seals, I have been using that lately and it works really well. but is Sodium Bisulfate a safer option?
 
thanks for the input guys........i havent up to this point had a problem with scale so i never had to soak in anything........It is too bad that these saw blades are scaling so bad cause a friend of mine gave me 2 full skids of brand new saw blades wrapped in cardboard .......approx 3000# of great flat new material......I have had no problems with the steel by itself either forged or stock removal so i will experiment further.........Ed....my forge seemed to me to be fuel rich when i was welding.....lots of colour in the dragons breath......what is an indicator of too much oxygen in my forge if the colour looks good......also the same day i did the layer damascus with these saw blades i did forge a cable damascus blade with no issues.......thanks for any suggestions
 
I would go with good strong white vinegar. It might be a little slower than the stronger acids and bases but it will be safer to use and dispose of. Just my opinion, for what it's worth.

Doug
 
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