Question about 7018 slag being really hard

[dwf_90]

I am wondering why sometimes the slag left from a 7018-1 rod is sometimes really hard to break off or instead off chipping of in pieces it crushes it to a powder? This occurs to me occasionally while welding root passes or even a hot pass. My bead will be flat, smooth, and perfectly stacked with no undercutting or discoloration of the weld. However instead of the slagging peeling off or chipping off easily it will be super hard to remove. I chip soon as the slag has cooled to a brown color and sometimes wait longer, but never while it is still orange hot. Any sugestions?

[jmccustomknives]

Howdy, generally speaking if the slags not coming off easily then you either have settings wrong, proceedures wrong (travel speed, direction or even weld angle).  Improperly cleaned metal or even rods with a little moisture although the latter usually results in pin holes.  Finally, you might even change rods.  I've been selling welding supplies for over 15 years and it's a source of ammusement as to the fact one guy wants this rod, the nexts wants the other because the other brand is junk.  Sometimes it's just the machine, it will weld better with one brand.  Sometimes it just takes some experimentation.  With welding, practice makes perfect.

[jeremy k]

When the weldment is up to temp and multiple passes are made and when the heat is just right and your weld is right - the slag will peel itself up behind you as you weld. This sure makes clean-up easy, just my experience that I strive for.

[Dan C]

Agree with what's already been said. Practice running beads and post here pictures of them. Good welds the slag often pops off by itself as they cool which is a good reason to wear eye protection.

[Backwoods Blacksmith]

Many cheep brands of 7018 will have non chipping or peeling flux.  Many weld process specify rod manufacture.  Lincoln is top of the line.  Hobart is near the bottom.  You get what you pay for.  Also keeping the rod in a heater and out of the weather helps in weld quality.  I have done welding in and on high pressure boilers and in refinaries and saw mills.  Boiler work Lincoln temp control rod, sawmills Hobart and welding in the rain.

[yahoo2]

Some of the high silica fluxes need to be properly set before you chip them, they stay soft underneath longer than you think. start chipping at the cold end of the weld first.

 

 

Drying the rods in the oven and keeping them in a sealed container during the days work helps a lot.

You can hear them run smooth and you can run a longer arc length to get the heat up.

 

If the slag is really sticking you may need to slow the travel speed down to keep the slag molten longer so it can finish gassing off and separating from the weld surface.

if you are running a weave pattern concentrate on the edges more don't just wander through the middle of the weld.

On small fiddly jobs going down a rod size will slow the travel speed.

 

Lastly make sure ALL the connections in the earth lead are in good condition, a good earth can make all the difference.

[dustyrode]

I don't exactly see any misinformation here, but most of it seems a little broad. If I understand your question correctly, it sounds like you're dealing with poor tie ins in the toe or shoulder of the weld. Often that means too low of amperage or improper electrode manipulation (moving the rod wrong). If you're a very knowledgeable and or experienced welder, this is probably very unhelpful info =D

[Robert Yates]

I would like to see your welds and /or some of the ones you are having issues with . It is hard for anyone to correct or help with words alone yes I can read what your are saying However, your welds would speak for themselves and would allow others to offer a much better input to help you .

 

Sam

[ThorsHammer82]

Pictures help.

 

as for calling out the welding machine/brand I'm going to call bunk on that. each brand makes a product for a price point and some people like one , and others like the other but as long as it's a recognized name brand you're fine. than it's just a matter of finding a machine you like and a rod that works well with it. basically different strokes for different folks.

 

The only time I have a hard time getting slag off is if there is something wrong with the weld. contamination/inclusions, temp issue, angle issue, etc. but when it's done right it just takes dragging something down the bead and the slag comes right off if it hasn't fallen off already.

[MLMartin]

It was always a fun game to see who had the longest slag peel at the end of the day in welding school. They were like little prizes! Sometimes some one could get a 6 or 7 inch one in a intact piece. Ha what a joke it was to make every little thing a contest. 

[Quarry Dog]

   I got my MIG 3/8" 3G cert this summer and moved on to a stick class that started in September, so take any of this with a grain of salt as I'm still a little wet behind the ears, but I'm not a total noob either. When I first started with 7018 I was short-arcing pretty hard when doing 3G and getting exactly the same problem that you are: good tie-in, flat bead, "Jon Wayne" slag.  I've since had much better luck hanging out about 1/8" from the surface.  I'm even peeling all the way to the top sometimes (8" piece), and the most I have to do is run a chipping hammer down the side of my weld.  I do have to run a little faster on narrow passes though, or it all starts running away from me.

  The other time I've had that problem is when I've grabbed rods that I suspect weren't quite dried yet.  I think another student had just put them back in the oven after they'd been out awhile.  I could see the shielding coming off of them in big chunks, instead of melting from the end, and it seemed like the arc was coming out the bottom  of the rod and scorching the stuff that I just welded over.  The only way that slag came off was in a powder after bashing its brains out, and even then there was some porosity in it.

   I hope some of this is useful.

[Hillbillysmith]

I find that 1 or more of the 3 basic principles are the culprit here:

 

1) Cleanliness of the bas material. Excellent rule of thumb, cleaner the better!

2) Angle of the rod during welding. Straight in with 0-15 degree drag angle. Rule of thumb, if there's slag, you drag!

3) Polarity of the welding machine. Always go with the manufacturer's recommendation. Rule of thumb, stick with DC current! If AC current is all you have, either get Lincoln Electric rods or get E-7018 AC welding rods.

 

There are other factors but I find these 3 to be the most common culprits of this issue. Of course quality of the rods, whether put in rod oven or not, and doing a root pass are also factors. If I ever have to weld a root pass with 7018, I try to either have a backing strip of some kind (aluminum, copper, brass, ceramic, fiberglass, etc.) or, if I'm able to weld the backside of the joint, butt it tight after beveling and back gouge/grind to sound metal before proceeding.

 

-Hillbilly

[Dodge]

Its been over 30 years since my first welding test but I remember lots of 7018 slag being hard to remove from the sides of the first weld bead. The test plate was 3/8" with a 1/2" gap(?) A 1/4" backing plate is tacked to both pieces holding the plates at the proper gap. Here's an example: Test plate. This plate needed no pre-heat. Consequently, the first welds bonded the the backing plate to the test plates. These would be cold welds in the spectrum of welding and the slag would be typically hard to remove. The standard practice was to grind out the edges of these welds to clean metal. With subsequent beads being applied, the slag became easier and easier to remove as the steel heated up until after 3 or 4 passes, the slag would begin to fall off. Dunno if this answers any questions but it was my experience about every time I took a 7018 test on un-beveled plates. Beveled plates were a different story. The thin edge of the bevel got hot enough right off to make the first cold weld slag much easier to remove.

[Iceman_713]

ive run into that plenty in the few years ive been welding, i find that hitting it with the slag hammer till it fractures then making a few passes on it with a wire wheel seem to work just fine for cleaning it out

[arftist]

I don't exactly see any misinformation here, but most of it seems a little broad. If I understand your question correctly, it sounds like you're dealing with poor tie ins in the toe or shoulder of the weld. Often that means too low of amperage or improper electrode manipulation (moving the rod wrong). If you're a very knowledgeable and or experienced welder, this is probably very unhelpful info =D

A knowledgable or experienced welder would not have posted the question. 

[Robert Yates]

DWF ,

 

are you still around ? how is your welding adventure coming along ?