Pipe welding top tips

[Richard.]

we never get taught downhand always need to climb up vertical

Up hill is the correct way to do it with most basic kit.
There are special machines with clever characteristics that allow you to put an open root in down hand.
This type of kit costs an arm and a leg but pays for itself in no time because the speed is many many times faster.

 

[Scotland90]

yea true. iv never had a try of the functions either. i take good information from my tacks they let me know if im right. any other good points i will need to know?

 

[Richard.]

I've been doing some quite recently all V up on plate which is handy as the conditions are fresh.
I did it with a 1mm solid wire root.
Gap was 2.4mm and root face 1mm
60 ° inclusive angle V prep.
17-19 volts
3.5-4.0 m/min wire speed (100 amps)
Then the fill and cap was done with a 1.2 rutile flux core 80/20 gas.
24 volts
7-8 m/min wire speed (180-200amps).
This was a sucsessfull full pen/fusion butt joint. Hope it helps.

 

[Scotland90]

I've been doing some quite recently all V up on plate which is handy as the conditions are fresh.
I did it with a 1mm solid wire root.
Gap was 2.4mm and root face 1mm
60 ° inclusive angle V prep.
17-19 volts
3.5-4.0 m/min wire speed (100 amps)
Then the fill and cap was done with a 1.2 rutile flux core 80/20 gas.
24 volts
7-8 m/min wire speed (180-200amps).
This was a sucsessfull full pen/fusion butt joint. Hope it helps.

i pretty much use the same but a .8 tip i also just fill with the same process iv never tried flux core yet

 

[Jim Davey]

Unless you have a backing tile FCW is no good for the root.

 

[Scotland90]

i can always make one

 

[Richard.]

Yeah you need a tight fitting backing for fc if your rooting with it and a bigger root gap. 3mm is a minimum. Ceramic tiles are probably best with the adhesive tape.

 

[Scotland90]

Yea. Why? Will u blow through, id probs give myself a bigger gap to use my root face for safety.

also with mag can u use 'arc length' to make adjustments during welding or is this a bad habit

 

[Richard.]

Yes with flux core you will burn through because your welding in spray transfer.
You can't adjust arc length on a GMAW machine as its a semi auto process and arc length wil always be the same. You can change your stick out and this will change as you weave up the joint but purposeful in and out adjustments will vary the current you are pulling which in turn may cause you root pen and fusion defects. I'd suggest you set your settings up right for the job and aim to keep your stick out consistent

 

[Jim Davey]

Porosity is also a major issue with FCW when used without a backer.

 

[Scotland90]

cheers. yea i meant manually pulling away a few mm's for a second too cool my pool and stop it getting worse? My aims keyhole control

 

[Richard.]

cheers. yea i meant manually pulling away a few mm's for a second too cool my pool and stop it getting worse? My aims keyhole control

Well it's best you don't because as you say when you pull away the current drops and so do your pen and fusion levels. It's much better to set up your machine and travel rate to remain in control over the full joint.

 

[Scotland90]

Yea i mean its not a problem im having i just wondered, in my opinion the fillets my arch enemy

 

[Richard.]

Are you talking fillet joint or single bevel T joint. Often confused but very different. Biggest difference is the full pen root usually looked for on a single bevel T. Fillet is easy but the single bevel is very difficult and demands high level of skill/set up to nail it properly.

 

[Scotland90]

no just ur normal t fillet, im more comfortable with bevels

 

[Scotland90]

i have never heard of a single bevel t but iv got a visual..wat would u be welding in that case?

 

[Richard.]

Same. I'd treat it as a butt joint and go for a full pen root then fill it and cap it. The difference would be when it comes to capping it I'd be then treating it like a fillet joint because that is what it becomes once it's filled. The difficulty is because it's very enclosed only half the size of a V prep so lack of fusion or if using mma/fcaw slag inclusion can be a common accurance. You won't get these problems with a fillet joint.

 

[Richard.]

Plate to pipe is very common for this type of joint. Simply because you can only access one side and if full pen is required you need to bevel the pipe edge before its offered up to the plate with a root gap. This is effectively a single bevel T joint.

 

[Scotland90]

ahhh i see im welding at my college all on 6mm plate, really easy to get full pen i also inherited the grinding tacks down to save myself time cutting my weld back. Any tips about stop/start and wat about prep on a bevel wat can i do to save time. Say all u got is a grinder no machines to bevel? Say my root face is choppy different sizes that means id need to speed up and slow down according to my root face

 

[Scotland90]

its all about the prep