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phelum
17th Mar 2008, 07:01 PM
Sometimes (especially today) my stick welding goes bad because the slag catches up and I am just firing metal into the slag puddle and can't see what is happening. Generally the weld is bad and even if it looks okay there is probably a big slag valley under the surface.

I find that some brands of rods are more prone to this but since I'm only an apprentice newbie it is pretty poor form to blame the rods. So I should be able to recover but I'm not sure how.

Is it worth reducing the rod angle to try and blow the slag back ? Or should I stop, chip the slag, and then continue ? Or (hopefully) is there a better approach ?

Thanks,

Wood Butcher
17th Mar 2008, 07:02 PM
The rod angle should be about 70deg regardless. Try turning up the amps a bit more and also you might be moving a bit too slow.

phelum
17th Mar 2008, 07:16 PM
The rod angle should be about 70deg regardless. Try turning up the amps a bit more and also you might be moving a bit too slow.
Thanks for the instant reply; what great service ! I couldn't go faster today because the weld metal wouldn't bridge the gap (these were V-fillet welds). If the slag catch-up happened to you would you stop and chip the weld before continuing ?

Claw Hama
17th Mar 2008, 08:38 PM
phelum, tell me more. What thickness steel, what size rods, how many amps are you set on? I have used many different brands of rods over the years, some ok, some pure crap but if I want a good clean easy weld I still go back to CIG rods. I would generally work with my welding rod at about 45 deg, roll from one piece of steel with your rod at a nice steady pace, go onto each piece of steel by about the rod thickness. Try not to have too big a gap between your pieces of steel as this can tend to collect slag. you want just enough amps so your welding rod dosen't stick.
And it doesn't matter how good you are if you have shity rods it's very difficult to weld. Always make sure you keep them dry and away from humidity etc.
Hopethis helps you on your way.

Grahame Collins
17th Mar 2008, 08:45 PM
By description its a tad difficult to diagnose but I am thinking that your arc length may be starting to get a bit too long.

As Woodbutcher says 70 degrees of drag angle.

Electrodes arent usually too bad but give us an idea and note the number on the stub end eg 6012 or 6013.
V fillet welds ?

Vee Butt welds (flush edge to edge) or Fillet corner welds (can be internal or external )
Stand by and I will whip some drawings up on MS paint.

Grahame

Wood Butcher
17th Mar 2008, 09:02 PM
If you are doing a vee butt welds, depending on the size you may need to do a few runs. What size rods are you using and what is the size of the vee's and plate thickness?

phelum
17th Mar 2008, 09:25 PM
phelum, tell me more. What thickness steel, what size rods, how many amps are you set on? I have used many different brands of rods over the years, some ok, some pure crap but if I want a good clean easy weld I still go back to CIG rods.
Today I was welding 5mm thick angle on the end of 5mm thick water pipe, 2.6mm Kobe type 13 rods, 90 amps. I agree about the differences between rods. I find Satincraft very nice and easy to use so if I have to do something serious (as opposed to practice) I will use a pretty blue rod. But I'm trying to learn so I'm using cheaper rods. They must be okay (or they wouldn't sell) and in fact I would say they are okay but much fussier and once a weld starts to go wrong I find it very hard to recover. Some welds today were okay but my hit rate was pretty lousy.

phelum
17th Mar 2008, 09:38 PM
By description its a tad difficult to diagnose but I am thinking that your arc length may be starting to get a bit too long.
Hi Grahame,
The welds were internal corner fillet welds and the gap varied from 0 to about 2mm. The pipe end was cut to a V shape (to fit the transverse angle) so I had to direct the arc to the angle to avoid melting the end of the pipe away. The weld was harder because I was doing vertical up from one side to the top and then vertical down on the other side. The long length of pipe was horizontal and I was welding a transverse length of angle on the end.

I was trying to keep the arc short but the end of the rod was in the slag (hence the title of this thread) and I really couldn't see what was happening under the surface. Should I stop and clean the slag away before continuing ? Like a fool (or optimist) I kept going but couldn't get ahead of the slag.

Claw Hama
17th Mar 2008, 09:57 PM
Still sounds like your angle of attack is too steep maybe forcing the weld into a pool like oxy welding rather than the arc pushing the weld and slag away from your molton pool of metal. I would say drop your hand a little. You should not have to stop and remove slag ever. Experiment a little with your angles keep your rod in there and pushing the slag away.

DJ’s Timber
17th Mar 2008, 10:06 PM
Can you move the pipe so that you're welding on the horizontal, do a bit then re-position because vertical welding is a a completely different ballgame to welding horizontal. To do verticals requires a lot of practice and the correct technique and a generally lower amperage setting.

phelum
17th Mar 2008, 10:40 PM
Still sounds like your angle of attack is too steep maybe forcing the weld into a pool like oxy welding rather than the arc pushing the weld and slag away from your molton pool of metal.
Thanks, I will try this. I've only ever used an oxy until recently and am still trying to learn this new fangled stick process. Oxy is nicer in some ways but gee this stick welding is quick and good when it works.

Grahame Collins
17th Mar 2008, 10:46 PM
was doing vertical up from one side to the top and then vertical down on the other side.

Betcha the slag problem was on the vertical down side and with those blue bastards.

Satincraft don't like to weld over themselves and do not weld downhill. The slag has less viscosity than the molten metal it is protecting and runs over the arc pool.

The Kobe is the much better rod and you could possibly manage a semi vertical down but with little strength. I would go with higher amps and a extremely short arc length.

Grahame

phelum
17th Mar 2008, 11:01 PM
Betcha the slag problem was on the vertical down side and with those blue bastards.
Yep, for sure I was stuffed on the downhill run. But I was lost even by the top because I was still pushing with the rod rather than dragging. Based on DJ's post above I think my approach was basically flawed. Would you (and DJ) recommend welding say 45 degrees of the pipe and then rotating it and continuing ? I've tried a few vertical up welds and got somewhere but I've never tried going around a pipe. If I do the pipe in sections is it better to do the section at the top (flat welds) or at the side (vertical up) ?

Grahame Collins
19th Mar 2008, 08:11 PM
I can help a bit .The pics below are something i done for someone else to help with v up.

Have a play around with the technique.
When I get time I will come back and help tune you up a bit hopefully.
Yes it says mig but applies equally to vert up in stick.
Grahame