Does pulse tig make any difference on 4130 chromoly tubing?
I think it does. But not a huge difference.
Some welders actually pulse the welding current with the foot pedal...and that is usually about like one pulse per second.
Personally, I see the benefit in using higher pulse speeds.
Like over 30 pulses per second.
On a metal like 4130 chromoly that hardens by quick cooling, it does not make sense to me to use a slow pulse speed.
But high speed pulse using over 30 pps helps with gaps.
And gaps are something everyone deals with.
When you are welding .030" thick tubing and you have a .060" gap, you can have a hole happen real quick.
A pulse rate of around 30 pps helps. It seems to make the puddle more stable and heat does not build up as quickly.
You really notice this when you are near an edge. the puddle just does not wander over to the edge as easily.
Pulsing the foot pedal like that is one way that some welders control heat input. I have seen also seen really good results without pulsing.
Some Old schoolers out there are still under the impression that 4130 chromoly is best welded with a gas welding oxy acetylene torch. Well thats the old way to do it, and it definitely works, but this guy knocks these welds out in jig time with a tig welder...and his welds look really good too.
There is a whole bunch of Engineering data available on the web that endorses tig welding chromoly with no preheat or post heat stress relieve treatment. As long as the tubing is under a certain thickness , it can be tig welded with E70S2 filler without problems.
I know one thing....I would rather tig weld it than gas weld it anyday.