Poor root penetration on vertical fillet weld with E6013 rods

[TechnicAl]

Spaldings have sold Lincoln for longer than I was there. Originally it was Welding Rods Ltd who supplied them but they were bought out by Lincoln.
They have never hidden the fact that they are Lincoln or vice versa.

I always thought they were (are) a good outfit to deal with (from a suppliers point of view)

I know the Bohler boss....

I wont tell him

 

[martinr]

I had a similar problem.........

Is your fit up good ? Grind both plates to remove the scale and make sure there's no gap at the corner of the join (the pieces we use were guillotined and uneven - this can act as a slag trap)

Have you done a Macro etch to see if you're penetrating into the plate ?

The weld profile looks a bit convex - might be moving too slowly or juice not high enough ? Mine got better with a flatter profile.

I'd be tempted to up the amps and try and move a bit faster. Or try a 3.2mm rod which obviously allows more current and keep the speed of travel up. Have you tried a run electrode negative to get more heat into the joint ?

Good luck- practice and time will sort it out !

Garreth

Hi Gareth and thanks for the reply.

I do try to grind any scale off and to get a good fit-up because, as you say, the guillotined pieces can create a natural trap for slag. But I appreciate the reminder because one can get complacent.

The macro etch does show penetration into each plate but not as much as I'd like to see, which has made me tend to keep the amps as high as I can.

I take the point about the shape of the profile and what it indicates about the speed/current.

I hadn't thought about going up a size to 3.2mm; if anything I'd have thought about trying 1.5,,, but I see your logic and I will definitely give it a go next week when we're back in.

I'm glad you mentioned welding electrode negative, because I have asked my tutor about that. The theory says that more heat goes into the job on electrode neg than electrode pos, yet most DC welding seems to be done electrode pos (DCRP) even when the rod will weld on either DC pos or neg. I can perhaps understand using DCRP for sheet metal but I don't understand why DCEN isn't the preferred choice where good penetration is essential. Maybe I'll swap the connections and see give it a go and perhaps do a simple trial to see how penetration changes with polarity in practice.

Thanks also for your words of encouragement. I intend to report back with results.

Martin

 

[scarecrow]

I'm glad you mentioned welding electrode negative, because I have asked my tutor about that. The theory says that more heat goes into the job on electrode neg than electrode pos, yet most DC welding seems to be done electrode pos (DCRP) even when the rod will weld on either DC pos or neg. I can perhaps understand using DCRP for sheet metal but I don't understand why DCEN isn't the preferred choice where good penetration is essential. Maybe I'll swap the connections and see give it a go and perhaps do a simple trial to see how penetration changes with polarity in practice.

Thanks also for your words of encouragement. I intend to report back with results.

Martin

your are opening a can of worms now
i allways vertical on electrode pos try it and see how you get on

 

[gavuk]

Thing is if lecturer and rest of the class can weld using the same parameters it has to be technique,,,,why is lecturer not telling you whats wrong?,surely thats what you are paying him for......make him demonstrate

 

[TechnicAl]

DC+ gives the best pen because the energy is directed through the arc

heat going into the job is NOT what you want

 

[Garreth]

DC+ gives the best pen because the energy is directed through the arc

heat going into the job is NOT what you want

I honestly thought it was t'other way round ! Thanks Al for your comment. Once again the forum has corrected me.

Cheers !

Garreth

 

[TechnicAl]

Its not easy. Ive always had a mental block about DC+ and DC- and Ive been doing this for 30 odd years

 

[martinr]

Thing is if lecturer and rest of the class can weld using the same parameters it has to be technique,,,,why is lecturer not telling you whats wrong?,surely thats what you are paying him for......make him demonstrate

Hi Gav,
There's around 9 in the class and I'm the only one doing MMA Level 2 (vertical). Most of the rest are doing MIG - no surprised there - and one or 2 doing TIG. MMA just isn't as popular as it was. I've had the tutor demonstrate the correct technique to me, which was a great help especially when I had too short an arc. Now, I'm quite confident that if I chopped up his work, I'd also find the inclusion at the root because I did exactly what he did. Nevertheless, with the kind advice I've got from this forum, I'm quite sure I can go back in next week and put this one to bed. I hope also to add some photos just to complete the thread.

Martin

 

[gavuk]

Martin ,glad your feeling more confident ...YOU HAVE TO GET ANOTHER DEMO AND CHECK THE TEACHER'S............I remember at college,i tried one handed ,two handed,handsheild ,face sheild,wrapping the electrode cable around my wrist to take the weight ,over my shoulder ,running left to right and down the plate ,etc etc ,I thought i was doing it exactly the same as i had been shown........it all eventually fell into place when the welding technician on the course checked on my booth ,told me to start welding grabbed my hand and guided the electrode,i soon got the hang of it ..i had the highest score of my apprentice group in gas and arc in basic joints etc.......the technician was my dad.........if your technician or lecturer grab your hand report them ......iI'm sure it will come together for you ,keep us posted ! If i wasn't doing conti shifts I would be doing an eve class myself....

 

[cookie munsta]

Have you tried the xmas tree method start in the join angled upward and go up about three to five mm up gently and then gently down to the left about half what you went up, or so it goes on top of your last across run (once you get it going)then across to the left slightly quicker and then back up into the centre of the join same as before. now where youve gone side to side thats ok but use the xmas tree with a few more amps ( it does not need to be pretty at first) you may have a bit of bulk in the middle and undercut on the sides this means your heat is good enough to too high. Don't go more than say 5mm either side of centre and count to yourself as you go up say 1 hold there 2,3 then down to the left is 1 then hold it 2,3across to the left is 1 thenhold it 2,3 and so on keep stick centred and angle it slightly to make the left and right movements keep angled upward with a 2-3mm arc, then after cleaning it, with the same angles change the heat setting to suit (usually down 5 or so amps) and do your side to side over the top from between your undercut and the job on the right to the same spot on the left and so on count also one side hold it 1,2,3. move 1 hold it other side 1,2,3. and so on
if you are going to fast to count then you are usually going too hot. not always but usually. it is alot like cooking, control your heat and get the timing
right but with the added variable of hand speed. a concept easier for us blokes to pick up. by the way your macro is great, to get a better look at what is going on in there fine sand paper it a bit more and leave it a bit longer before washing it off. best of luck with it. oh it is much easier to do over head from veiwing position that is above the stick than under it but it is always easier with practice

 

[martinr]

Have you tried the xmas tree method start in the join angled upward and go up about three to five mm up gently and then gently down to the left about half what you went up, or so it goes on top of your last across run (once you get it going)then across to the left slightly quicker and then back up into the centre of the join same as before. now where youve gone side to side thats ok but use the xmas tree with a few more amps ( it does not need to be pretty at first) you may have a bit of bulk in the middle and undercut on the sides this means your heat is good enough to too high. Don't go more than say 5mm either side of centre and count to yourself as you go up say 1 hold there 2,3 then down to the left is 1 then hold it 2,3across to the left is 1 thenhold it 2,3 and so on keep stick centred and angle it slightly to make the left and right movements keep angled upward with a 2-3mm arc, then after cleaning it, with the same angles change the heat setting to suit (usually down 5 or so amps) and do your side to side over the top from between your undercut and the job on the right to the same spot on the left and so on count also one side hold it 1,2,3. move 1 hold it other side 1,2,3. and so on
if you are going to fast to count then you are usually going too hot. not always but usually. it is alot like cooking, control your heat and get the timing
right but with the added variable of hand speed. a concept easier for us blokes to pick up. by the way your macro is great, to get a better look at what is going on in there fine sand paper it a bit more and leave it a bit longer before washing it off. best of luck with it. oh it is much easier to do over head from veiwing position that is above the stick than under it but it is always easier with practice

Thanks, yes I tried the xmas tree method and again found that I wasn't getting perfect root penetration. When we're back - in 2 days - I'm going to try a 3.2mm electrode on higher current for the root, and then, if this solves the root penetration problem, 2.5mm for the cap. Anyway, I hope to get some macro etch photos on the results and report back.

I really do value everybody's kind help.

Martin

 

[Lewis Medlock]

Good luck with it Martin, I've just done the vertical MIG bit of my course and I'm moving on to MMA next.

Last year I came very close to throwing things about the workshop trying to get the MMA butt joint (in the flat position) before I finally nailed it!

All the best, Jim

 

[martinr]

Thanks, yes I tried the xmas tree method and again found that I wasn't getting perfect root penetration. When we're back - in 2 days - I'm going to try a 3.2mm electrode on higher current for the root, and then, if this solves the root penetration problem, 2.5mm for the cap. Anyway, I hope to get some macro etch photos on the results and report back.

I really do value everybody's kind help.

Martin

I tried a larger electrode (3.2mm) and lots of juice but the root penetration was no better; I think the electrode diameter was too large to get into the corner. So I returned to the 2.5mm electrode at 80-85 Amps (high end of the range) and a slope angle of 90 degrees and, instead of laying the bead vertically up in a straight bead, I put in a very small 45 degree weave as I went up, just enough to catch each edge of the joint. That helped pull the profile of the weld to a flat/concave profile with no tendency of the weld pool to fall down under gravity. I seem to remember I learned this lesson many years ago but having gone rusty in the meantime I forgot it. For the sake of completeness, when I redo the Tjoint, I'll post the macro etch photo.

In the attached photo of the lap joint vertical up, you can make out the fairly narrow root run and the single weaved cap over the top. (Please ignore the file marks at the edge of the fillet.)

Thanks to everyone for the kind and patience help you've shown.

Martin

 

[Lewis Medlock]

I tried a larger electrode (3.2mm) and lots of juice but the root penetration was no better; I think the electrode diameter was too large to get into the corner. So I returned to the 2.5mm electrode at 80-85 Amps (high end of the range) and a slope angle of 90 degrees and, instead of laying the bead vertically up in a straight bead, I put in a very small 45 degree weave as I went up, just enough to catch each edge of the joint. That helped pull the profile of the weld to a flat/concave profile with no tendency of the weld pool to fall down under gravity..
Martin

Great stuff Martin, thanks for the update.

Jim