How to reduce crater in welding?

Tue, 31 Aug 2021 10:21:02 GMT

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Hi,We are working on structural steel works including; fabrication of rafters, columns and crane beams etc. as per the requirements of AWS D1.1 standard. We found a lot of crater imperfections at the end of welding beads. I want your recommendations on how to avoid this defects. We are using 7018 electrode on grade 50 mild steel.
Reply:I am not sure if this is what you are looking for but here is a picture of A36 1/4" flat bar weld on some brackets we made using Lincoln 5/32" 7018 both edges beveled.  I hit the end and pull back about the width of the rod about a second before pulling off.
Reply:Originally Posted by aapossienI hit the end and pull back about the width of the rod about a second before pulling off.
Reply:Originally Posted by Albert FelixHi,We are working on structural steel works including; fabrication of rafters, columns and crane beams etc. as per the requirements of AWS D1.1 standard. We found a lot of crater imperfections at the end of welding beads. I want your recommendations on how to avoid this defects. We are using 7018 electrode on grade 50 mild steel.
Reply:You can start at a thinner edge so that the cold weld will not show at start.  End at a thicker section then hesitate as you mention tracking back over the bead and lifting off.  There is nothing wrong with ending say an inch or two early then striking up at the end of the joint and welding back into the previous bead ending and filling on the crater you left.  The inspector is looking for the physical notch that the crater creates.  If you see that you left a crater clean the area, strike up and fill it.  One of the best things you can do to prevent craters is to carry a flashlight and use it.  If you angle the light from the side it will show up undercut and a variety of problems before the inspector uses his flashlight.  :'))  Too many people run a bead and consider the weld done.  A quick inspection of your work will prevent embarrassments.  We are not perfect. We all make errors. The screw up is when you don't self inspect.
Reply:Originally Posted by Albert FelixHi,We are working on structural steel works including; fabrication of rafters, columns and crane beams etc. as per the requirements of AWS D1.1 standard. We found a lot of crater imperfections at the end of welding beads. I want your recommendations on how to avoid this defects. We are using 7018 electrode on grade 50 mild steel.
Reply:Originally Posted by Albert FelixHi,We are working on structural steel works including; fabrication of rafters, columns and crane beams etc. as per the requirements of AWS D1.1 standard. We found a lot of crater imperfections at the end of welding beads. I want your recommendations on how to avoid this defects. We are using 7018 electrode on grade 50 mild steel.
Replyause at the end of the weld.  Keep welding, stop moving.  I cound to three.DavidSent from my SM-T900 using TapatalkReal world weldin.  When I grow up I want to be a tig weldor.
Reply:I'm having a little trouble getting my head around why 7018 stick rod seems to be the primary welding process where Albert is working.   From the OP in this thread it sounds like it's a production structural steel shop that should be using either Flux or Metal Cored wire welding.
Reply:If it's what the engineers desire, it's what the engineers desire. Who are you to decide what another person "should" be using on their job? It's quite likely they've thought it through and 7018 meets their requirements best, whatever they may be.2000 Lincoln SA-2501974 Miller Dial-Arc 250
Reply:Originally Posted by Hillbilly WelderIf it's what the engineers desire, it's what the engineers desire. Who are you to decide what another person "should" be using on their job? It's quite likely they've thought it through and 7018 meets their requirements best, whatever they may be.
Reply:more likely it is not so much lack of pausing to fill crater at end of weld but more like a magnetic arc blow issue.5/32 rod at higher amps can give extreme arc blow causing arc to go to side of rod. with certain shapes and at edges it can get bad. the arc blow makes end of weld bad. i tend to lean the rod to combat arc blow but some welders who do not adjust rod lean or tilt depending on arc and weld puddle can experience problems. .literally arc blow can be 10x worse at 150 compared to 100 amps and be 100x worse at 200 amps. fillets welds i often have seen arc blow. you can but butt weld 1000 years and never see arc blow and fillet weld literally 1 minute and seen extreme arc blow. very much depends on what shape you are welding.
Reply:Originally Posted by HT2-4956Hill,I'm wasn't trying to make any decisions about how Albert's place of employment does any thing.   It's just with the kinds of basic questions he's been asking on the forums it makes it seem like were he's working doesn't have the kind of engineering background / experience you expect to find in a shop doing Code Quality work.   I'm not trying to put Albert or the shop he's working at down it's just that there's something about all this that's really got my curiosity peaked.
Reply:I worked structural all my life. When the LN-22s came out in the early 1980s, then a few years later the LN-25s came out. Wasn’t very long until I would go for years without seeing a stick electrode on the job site. When the contractors have to pay union scale, production is all the contractors think about! Production = wire feeders!Don’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Originally Posted by Albert FelixCan you please elaborate it. I need more details on this preventive step. Thank you :-)
Reply:Originally Posted by CEPI worked structural all my life. When the LN-22s came out in the early 1980s, then a few years later the LN-25s came out. Wasn’t very long until I would go for years without seeing a stick electrode on the job site. When the contractors have to pay union scale, production is all the contractors think about! Production = wire feeders!