HTP Tig Welder Settings

This week I am using an HTP tig welder. It is the  Invertig 221H model AC DC tig welder and one of the settings on this TIG  welder is AC frequency.


AC frequency is adjustable on many tig inverters but  there is very little information on where to set the AC frequency for different jobs.
So hopefully, this video will shed some light on that.


First of all, one of the main benefits of having an inverter like this HTP Tig welder is AC frequency adjustment.
In the past, we were stuck with 50 or 60 hz.  It seemed fine and we made it work.

But now we can adjust AC frequencies all the way up to 5000hz on some tig welders. ( like the Miller Dynasty 350)

Why would anyone want to tig weld aluminum at 5000hz?

Frequencies like 5000hz may seem unnecessary for the average user but there are segments of the welding industry like tube mills that are discovering that increased AC frequency translates directly into increased travel speed....and that means increased production. and that means more $$$$$.

Most welders like me and you will never have the need to tig weld with frequencies of 5000hz.  And besides, the high pitch whine at high frequencies like that is very annoying.

But I do adjust the AC frequency setting on every inverter I use. ...I routinely use ac frequency settings as high as 150hz when I need to focus the arc.  And I have talked with many welders who see benefits up to around 400hz. But at 400hz, things can start happening to your tungsten that are hard to explain.

You really need good quality tungsten at 400hz.

For this Video, I started out welding one inch thick ( 25mm) aluminum with a setting of 50hz on the HTP Tig welder, because  a low frequency like 50hz actually puts more heat into a thick part. If you think about it , it makes total sense. More time is spent on the negative and positive currents and less time is spent switching back and forth.

Next, 60hz was used for overlay type beads that would be used in build up of castings or worn parts. 60hz is what I am accustomed to from all those years of welding with transformer style machines. It worked just fine way  back when...and still works.

For welds like an edge weld on a piece of .125" (3mm) piece, you can benefit from a more focused arc. So 100hz is a good choice for those types of welds.  I also set the AC balance to 60%en to allow for plenty of cleaning action so that the puddle would wet out and flow clean at a minimal heat.

But stepping down to thinner material like .063" (1.6mm) thickness, a setting of 120hz worked great along with dropping down to a 1/16" (1.6mm) electrode.

The last application was a fillet weld on a Tee joint in .063" (1.6mm) thick aluminum. This joint is difficult. Its hard to maintain a small weld while getting the puddle to fuse into the root.
A setting of 150 hz helped in pinpointing the arc so that I could drive the molten puddle down into the root of the joint.

So there are a few practical applications for setting AC frequency .

a recap:

  • one inch thick (25mm thick ) metal with  no preheat  worked well with  50 hz
  • overlay or build up beads that need to wet in nicely  will work with  60hz
  • .125"  (3mm) edge welds where a focussed arc helps will work at 100hz
  • .063" (1.6mm) edge welds where an even more focussed arc helps will work at 120hz
  • .063" (1.6mm) tee joint fillet weld works great at 150hz

This HTP Tig welder also has some unique   settings that are usually found only on higher priced machines.


See more on HTP Tig welder settings


more on all types of Tig Welding