Tips for running a root pass with a 7018 3/32 rod...

by Copelan
(Brookhaven, ms)

Anyone got any helpful tips on running a rootpass with a 7018 3/32 rod on 3/8 test plate. I'm in a welding program and I'm trying to test out for shipyard. I'm spacing my root pass about the width of my rod. With a little landing and my rootpasses have been running up one side of the bevel and not tying in to ther side giving lack of penetration and cracks when the backing strip is washed off. I run my root pass at around 75 to 80 then a hot pass at about 85 to 90 then to filler beads then 3 or 4 beads for a cap. I need any good advice for the process any tips or tricks will be appreciated. HELP

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jody here with a few tips,

with a 3/32" 7018, I would not use a land, and if the backing strap is 1/4" and the gap is specced at 1/4" use a 3/16" -1/4" gap and about 85-90 amps.

if the backing is 1/8" then the gap should be about 1/8-5/32"

keep a tight arc and as close to a 90 degree rod angle as you can

anyone else got any tips?

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Jul 04, 2012
4 i want NEW
by: Aavesh

Guys pliz help me i am from india and i really want to make 6g joind i am a weldar but i never hat to do 6g joind i love waldin i can do anyting 4walding pliz help me guys

Jun 04, 2012
Backing bar root pass w/ 7018 NEW
by: Jim

This will reflect much of what has been said already so take what you want and leave the rest. Clean the backing bar and plates spotless shiny-no millscale. Use a knife edge (no land). Clamp the backing bar as tight as possible before tacking, if you have ANY gap, no matter how small, you will have a slag inclusion and bust out on the bend. With 3/32" 7018 wire turn your heat up to at least 90 amps in all positions with the exception of vertical up - try 85 amps for vertical. Once the arc is struck and you have a hot puddle, walk the puddle into the root opening weaving the rod from side to side. Direct the arc into the toe of the plate, you will see it burn out the knife edge. Once the knife edge is burned out hold the rod until you see the puddle appear to "sweat" the slag out of the pocket. This displacement of the slag tells you that the pocket is full of metal and won't be undercut. Once the slag has "sweated" from the pocket, quickly weave to the other toe and repeat. Be patient, watch the puddle closely, and make small incremental forward progression with each weave. Done correctly there will be no need for a hot pass, only filler and cover passes. Hope this helps.

Apr 25, 2012
up your heat NEW
by: Dan

I have never understood the reasoning behind the 7018 with backing weld test. Running roots with 7018 sucks because the flux is very invasive and ductile. Not only that, as you have seen, 7018 is a low to mid penetration rod, unlike 6010 which is a gouging rod, far more suitable for root passes. Anyhow, to answer your question 7018 open butt roots welded over a backing plate need to be burned in. If memory serves me the amperage range on 7018 3/32 is 75 to 115 amps. That means you are running right near the minimum on your root, 75 amps with 3/32 7018 is about right for welding 1/8 to 3/16" plate. Test cupons are usually 3/8 or 1/2" thick and regardless of the fact that the backing strip is thinner, I find that 90 amps is a good setting for the hot passes and cap but the root needs to be ran at around 95 amps. You know the heat is right on a backing plate root when the bead lays almost flat, it looks like this because the weld is penetrating rather than cold lapping and piling on top. Weave your root side to side in a z pattern and pause for a tick on the sides to ensure tie in and avoid undercut. Ensure that as you are doing that your arc is pointed at that part of the plate you are intending to tie in to. I.e. point the tip of the rod slightly toward the side of the bevel as you come to it. Another thing, you don't want a land on your bevel for any test unless you are running a 6010 root. A good rule of thumb with 7018 is that if the bare end of the rod (the one that goes in the stinger) wont fit in the corner of any crack in your weld area, you will have slag inclusions in that corner. 90 degree corners are bad news for 7018 especially vertical and overhead. Those lands will probably fail you the test even if you do get your root to fuse. That can also apply to your hot pass, if you have a hot pass heaped up in the middle then you have very defined cracks on the side that fill with slag. The technique of pausing on the side as you go and doing the z pattern helps a lot there too. Usually I will pause for a quick 1 2 count (probably about 1/2 of a second) on the sides as I weave my hot pass to ensure fusion and keep the middle from being heaped. Hope that helps,
Dan

Nov 05, 2011
Where's your work lead?
by: Griff

Your root pass might be running to one side because your work lead is on that side. Try repositioning the work lead to where your welding toward it (i.e. equidistant to both bevels).

That aside, it might just be your travel angle or your weave pattern.

Nov 05, 2011
E6010
by: Anonymous

I never used Basic rods for a root pass, here in Europe for a root pass we only using rutile or acid rods, and most common is E6010, than for a finishing comes 7018.

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