Your 4600 running watts generator will power a portable mig welder with 030 or 035 fluxcore wire at a plenty high enough setting to weld the pipe.
Welding galvanized fence pipe.
Fluxcore wire welding works just fine in the field for fence work.
Arc welding is a versatile method that uses alternating currents to create a high heat arc that melts your flux.
That is what i primarily use on the truck for fence and railing repair and installation.
If you can work outside when using an arc welder.
Welding thick galvanized coatings or butt welds or welding creases or corners where the galvanization naturally builds up benefits from grinding the galvanization off first.
Use an arc welder to weld galvanized steel.
A standard arc welder is undoubtedly the best way to weld galvanized steel.
As long as the zinc oxide gets access to air to burn off.