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SS pipe weld
I'm starting to learn how to weld stainless steel pipe scd. 10 and up scd. 40 Im not to certain on how to determine when to use High Frequency. Is it just on the root pass for arc starting or what?
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Eicon,
Simply put the HF starts the arc on AC and DC. HF also maintains and stabilizes the AC arc with the exception of the Dynasty inverters. The Dynasty inverters have an advanced squarewave arc on AC that maintains itself without HF once it is started. The HF is used to start the AC and DC arc on the Dynasty. There may be other inverters on the market that only use HF for arc starting and not arc maintenance/stabilization. I mentioned the Dynasty series since I am very familiar with these machines.
When TIG welding with DC the high frequency (HF) is simply a method to initiate the arc. The HF provides a path for the arc to travel between the tungsten and the workpiece. The alternative is to use a touch start or "Lift-Arc" as Miller has it patented.
When welding SS pipe either method will work fine. It is really your preference. It has nothing to do with root pass, hot pass/fill pass, or capping passes. If these SS pipe/tube welds are critical, a backing shield of argon gas is appropriate. You can stuff the tube ends with a sponge or even tissue paper to plug the ends. Then insert a hose from you argon tank through the tissue or sponge to allow the argon to fill the pipe. By purging the inside or the SS pipe you will eliminate any oxidation problems on the inside of the welded seam.
This is more than you asked and I hope I have not caused additional problems with the extra information. -
HAWK has pared the course!
Hawk, you pared the course with that answer or even - it. I have the 301G Trailblaizer, can I simulate High Freq in anyway or do I have to get an Arc starter and Stablizer. If so whats recomended for welding SS and alluminum for that matter.Comment
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Eicon,
The TB 301G offers a scratch start TIG feature for DC only. To use HF for non contact starting a HF stabilzer box is required. The HF-251D-1 in the 120VAC input supply model would be a good choice.
The new TB 302G offers Miller's "Lift-Arc" technology, but the HF box is still required for HF starts and AC welding.Comment
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Eicon,
AC for aluminum and DC for SS.Comment
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