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#1
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forge weld strength ?s
Hi again guys
I've been wanting to do forge welded folded axe-tomahawks for a while but i'm still in the welding practice stage where i'm just heating 1 1/4"x1/4" mild steel rectangular bar back on itself, leaving a 1" or so unwelded loop at the end, so i can get a chisel to it and try to pound it apart to see if my "weld " holds together. When i grind the edges of the bar to expose the joint lines they're pretty tough to see, seem blended in well, i think. But... every time i lay a bar on edge, on the anvil, put a chisel edge into the joint gap at the loop, add about 8 or so solid hammer smacks on chisel, a whole 1" long section of the "weld" separates. Its not peeling apart, but more like springing apart, letting go all at once. Have you ever chiseled apart a weld (while unheated)and what does the surface of the metal look like where they separated if properly fused. What i'm getting looks dark and dirty. My computer died and i'm on an old gateway that i can't hook my camera to but, Any thoughts on how strong or how to test a weld? Should you be able to , for example, pound a tapered drift into a welded loop like i'm describing, with the loop at forging temp or even cold and not have it separate? Thanks for any thoughts |
#2
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A ?true weld? is at or above the melting point. A ?forge weld? is not. The best a forge weld can be is about 80-90 percent as strong as the base steel.
However, a good true forge weld holds up very well for most practical purposes. Last edited by Tai Google; 10-12-2009 at 12:53 PM. |
#3
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I would suggest 2 things... that welding hotter for the material you have may secure a better bond, and that welding higher carbon material will give you more strength at a given temperature, since the melting point of steel decreases as the carbon content increases.
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#4
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For that type of hawk, just use the drift as a mandrel to hammer the loop around or over. Don't try and stretch the loop out with the drift.
Chris is right, the closer to the melting point you can get without actually melting or burning the steel the stronger the weld will be. |
#5
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In addition to the good advice above, try grinding off the mill scale from your mild steel strap and do each welding sequence three or four times. If there's black grit in the seam, it's not welded very well. A good weld when split cold will be shiny, but not smooth.
Trying to stretch the eye with a drift is a sure way to split the weld, that part is the weakest. |
#6
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Sometimes, it can help to "forge braze" the part of the seam closest to the "eye" with copper. That gives the eye a bit more strength without over heating or over forging the steel trying to forge weld it right there.
You don't want to burn it there or get it too thin. Try to do the welds at a low heat repeatedly in a reducing atmosphere with plenty of flux and light rapid blows, as you can... ... Don't beat the back of the hawk with a 12 pound steel sledge hammer, diving it through a mesquite log. I found that out! |
#7
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Thanks much! for the help fellas.
It's finally supposed to quit raining this weekend and i want to try a bunch practice welds, just folding the bars back on themselves. Then see how hard they chisel apart at the seams. For only about 40 bucks i can buy a folded mild with carbon steel bit hawk head that i think i'm gonna cut into 1" strips and see if i can chisel them apart, just to see what a probably properly done one is like versus what i come up with. Thanks again |
#8
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What kind of flux are you using, and when are you applying it? Should flux on the rising heat as soon as flux will stick but before much scale has formed, hold it at the welding heat long enough for the flux to do its job, test for proper temp with a heavy coat hanger wire(low carbon wire) forged to a fine point, or a 1/4" mild steel rod forged to a long thin point. It should stick lightly when applied to your piece if held there on a fluxed area for long enough to come up to temp. Learned this from Bill Fiorini as a good way to check for proper temp., and a way to learn what proper temp. was.
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#9
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Thanks alot Martin, especially the pointed rod to piece test.
Unfortunately, i haven't gotten a chance to try using the info you guys have given me in this thread yet. The light rain-drizzle just does'nt want to stop here. |
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forge, forging |
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