Thread: Welding 4mm Pipe

Hi Cutting Edge,
Given that our pipe is square at the ends, we can butt weld with ease.

Square cut edge is prepped up shiny clean. Migs hate dirty and contaminated metal and will reward poor prepping with a poor deposit.

Looking at the pipe end on divide it up into 90 degrees sections and mark those four places as tack positions.

Use a 3mm or even 4mm gap set up on some parallel electrodes or sheets.tack in 2 places and pull out spacers.


Tack the other 2 places and fill in the gaps.

• With pipe axis in horizontal weld from 12 to 3 o'clock, tack at 12 o'clock and weld down with the wire at 30 degrees or so below the horizontal.
  
• Roll over and do the opposite segment and then the other two.

Cut some little scrappy bits to do some practices on ,OK?

Clean all the spatter out of the nozzle or Murphy will make it fall off into your weld.



Too bloody easy,

Grahame

Thanks for the info.

As a rule of thumb should you be using the same power/wire settings for square section of the same diameter, or do you slow the wire speed down a bit for the pipe.

Hi Cutting Edge,

The wire speed determines amp setting and is adjusted mainly without too much regard to the position. The trick is to get the arc "crackling " at its highest pitch.

The go is to set the voltage to suit the material thickness so that the arc is specifically adjusted to the requirements of the joint.

Cheers
Grahame

In our case it is an open square butt joint. The technique (once the arc is adjusted) is to place the bead to bridge the gap ( begin at the top 12 O,ck).

The rule of thumb is to make the gap approximately the same as the wall thickness of the butt joint.

The best description I can give of the technique is to start by bridging the gap,ie , weave one side to the other and as one moves the wire down into the vertically down travel it changes to getting the wire pushing up into the arc pool as you travel down.

If you have a digital read out, try somewhere around 180 amps at 18 volts.
If there are many joints to do I have some tricks to show you how to reduce set up time.