30mm Plate Butt Welds

[Bede]

As seen on my acid etch thread I'm currently making some hefty lifting beams.

I thought this was a decent opportunity to show, pictorially, how to build up heavy butt welds.

The photos show a double 'V' joint of combined 60 degree prep with roughly a 2mm root face and 2mm root gap. I say roughly because this is a job in real time so they've been gas cut by hand and quickly ground up. They are not perfect and I've not run test before to get every setting exact, in industry when you're doing this day in day out you get one crack at it. This isn't a college exercise so my settings were pulled out of my head from experience, quick blast on scrap to check it's ok and away we go.

So, to start, I place a light-ish root run. I'm running at about 28V with 1.2mm wire running at around 12 M/min. I'm erring on the side of caution here. Since it's a double 'V', I'd rather my root to be a tad light rather than too much and then burning through, requiring remedial work. If this were a single 'V' I probs would have ran a quick test piece to get it spot on, penetration-wise.

So, here's the first side root. 1st as welded, then cleaned up with a wire cup brush.

 

[Bede]

So next up, I'm cracking the power up to around 31,5V with a wire feed of around 14M/min. I'll then run a fillet over one half of the weld and the face of one side of the 'V' prep. I'm building up a bead that just licks the top edge of the prep.

Pics show as welded then cleaned.

 

[Bede]

So now, those two welds have created another nice 'V' to fill. This time I'll be building a bead on the left, slightly overlapping the top edge of the weld prep, protruding just above the level of the parent metal and overlapping the left half of the previous run, which will then create a shallow rut for a final cap just to the right of this bead.

 

[Bede]

So, the weld to the left in the above picture is at finished size and the weld to the right is a little below the surface of the two plates to be joined. One final cap and this face is done. If required, this can then be dressed flush but that's of no consequence on this particular job so the welds will stay as they are.

 

[Bede]

I did, of course, create the worst welds for the joint I decided to photograph! Bit of a banana going on in that last cap above. The smoke billowing off welds of this power doesn't half clog up your field of view. Well, that's my excuse and I'm sticking to it.

Anyway, there are five of these joints down the length of the job so once all five are done on this side, it's then turned and we fill the reverse.

Since I'd gone a tad light on my initial root on the first side, I can now give it some welly on the root to the other side as I want to burn good penetration right back to the reverse of the root on the other side. So, it gets it good and proper now with a higher powered, larger root. This then means I can cap the remaining prep with two slow passes rather than the three required on side one.

The photo below shows the hotter root then it's just a repeat of the process as described above.

 

[Liquid Metal]

Nice bit of work there, jobs going well by the looks of it!! :thumbs up:

 

[Bede]

Cheers. This one should be done in a couple of days.

Being a bit of a sad b****** - I've just been cutting something so thought I'd prep a couple of the 30mm offcuts with a view to replicating the butt welds above, same settings and method as above, then chop it up and acid etch to have a gander at the penetration. If I get a chance at some point next week.

 

[F.J.]

Absolutely love heavy engineering, I did wonder how you had the plate clamped to prevent either side lifting whilst welding the first side then all was clear when I saw it welded to the beam. I have a bucket to repair in the shop at the moment and need to fit a new 50mm thick cutting edge and teeth. Just got the arduous task of removing the damaged cutting edge first!

 

[Bede]

Ha, done a fair few heavy bucket repairs and wear strip replacements. Horrible! Always good to keep you warm in winter though!

 

[Spark plug]

Did you let the welds cool between passes or run hot straight over the top?

Cracking job tho.

 

[Bede]

Run hot, two at a time. Root one, move to root the other, clean up both, then hot pass one, then move to the other, etc.

 

[Richard.]

Did you work to an interpas temp on the little test plate.

 

[steve t]

Nice heavy work there

 

[Bede]

What test plate?

 

[Richard.]

Sorry not test plate. The double V plate your building up. Did you need to follow an interpass temp when building it up?

 

[Bede]

No.

 

[arthur]

Nice, done a few digger buckets/teeth, I enjoy working with big steel, those photos look great.