My 10+ year old TIG welder has pulse capability. Pulse works well, easier than trying to modulate with the foot pedal. Not sure why cold welding is so named as it clearly isn't a cold process. It's just a series of tack welds, essentially an extreme example of pulse welding.

Andrew

My TIG welder also has the pulse capability. As Andrew pointed out this is NOT a cold process, rather it is a way to control heat input.

Especially on thinner materials, with a continuous arc not only melts the metal to form the weld bead, but also can add so much heat into the surrounding metal that the entire piece burns through before one has successfully welded it.

The pulse process allows the operator to define the on-off welding current time such that only the required amount of heat is used. Usually, this just means a more controlled welded seam, without dumping unneeded additional heat into the surrounding area. And, yes, the process can be so slowed down to the point that it is, in effect, a sequence of 'tacks'.

Another benefit of the pulse process that I might mention is that used at higher frequencies the pulsating arc agitates the weld pool and encourages a better blending together of two edges of butted metal.

Of course the pulse process is only another 'tool' and one usually has to practice a bit to find the correct pulse settings (frequency, on-time, base current). Best to do this on some scrap before you tackle the actual work piece.

One other use that I have found for the pulse process is smoothing out the edges of extremely thin cut metal (such as stainless steel). For this I set the pulses at a somewhat slow rate (something like 2 to 5 pulses per second) and the welding amperage only sufficient to 'bead' the edge but not cause it to melt back. In this way, I can run the pulsed arc along the edge of the metal, the series of little beads forming a smooth, rounded off edge.

I would suggest the video link below as a good introduction to possible uses of the pulse feature.

Testing TIG Welding Techniques