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#1
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Mega blister
I was out at the forge playing around with some 1084/15N20. I started with 7 total layers. After about the 3rd cut and fold I started to draw it out. Reheated it and noticed this huge bubble on my top layer, about a quarter of the way in from the edge. I beat on it a few times but it wouldn't go away. I let it cool off and ground it out. It was the size of a quarter, maybe bigger. What would cause this? When I ground into it I didn't notice anything in it. I've heard of small bubbles and things but something this big has me wondering...
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#2
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Maybe someone with a lot of forging experience will jump in here with something helpful. Until then, let me guess that you managed to completely weld the edges of that circle but missed the center of it because there was something in there that prevented a good weld without being coarse enough to show up like an inclusion.
If I'm understanding correctly, you're using a hammer and at some point you're folding the steel to increase your layer count - literally, folding the steel. If that is correct you're setting yourself up for problems like that because you'll be trapping all sorts of stuff between the folds even if you cleaned it before you started on the heat you would use to do the fold. In short, you're not cleaning the steel properly. This is a lot of work - and maybe you're already doing this and I'm off base but you didn't say so I'm guessing. What you should be doing is: 1 clean all the pieces of a new billet until they are shiny (grind to white steel) 2. stack the pieces and then run a weld with an arc welder (or TIG, MIG, or whatever you have) across the edges so that the 7 pieces you started with become a solid block with no real air space between the pieces - like a deck of cards with several lines of glue on the edges all the way around the deck 3 forge weld the billet making sure you get a solid weld, work your hammer from one end to the other pushing out the flux as you go 4 when your weld is good, draw out the billet until it is two or three times the original length 5 at this point, I put the billet in wood ash to anneal overnight but most guys will continue and work the steel hot. So, hot or cold, when you continue... 6 CUT the bar into two or three equal pieces (not fold) 7. if you're working cold you can go to the sander now, if hot most guys use a big angle grinder but each section of that billet need to be cleaned again just as it was when you started. Not one spec if ash should be left and the steel should be as close to flat again as you can get it. For a really important billet, I'll mill the pieces flat. If it is flat there's less chance of trapping crap between the pieces on the next weld 8 re-stack the clean pieces and arc weld them together again (hot or cold you still weld it) 9 back into the forge to do the forge welding part 10 repeat until you get the layer count you want Yes, you lose a good bit of material this way. Now you know why damascus costs so much. But, if you don't do things (more or less) this way it's likely you'll lose the whole billet to inclusions, cold shuts, or whatnot... |
#3
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Your right ray. I just cut 7/8 of the way thru then cleaned it with a grinder while it was hot, folded it and began the next welding session. I guess I'll start to cut all my pieces and hopefully keep it a lot cleaner. Thanks for your wealth of information Ray.
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#4
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Trapped flux. Forms a blister-like bubble.... use a sharp punch to pop it while hot, re-flux, and continue... this does not always work, but most of the time it will fix the problem. Ray gives some great advice. Cleanliness and temp control are the 2 most important aspects of forgewelding. Confidence and compatable steels help a bunch, too....
__________________ A good friend told me one time about forging "What is there not to like, you get to break all the rules you were told as a kid, don't play with that it is sharp, don't play with fire, and don't beat on that" Wade Holloway See some of my work. |
Tags |
1084, advice, angle, art, back, billet, blade, block, cleaning, cold, damascus, edge, flat, folding, forge, forging, hammer, heat, hot, making, material, steel, weld, welding, white |
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