Materials
How hot and fast: amp and speed tips for galvanised steel
Quick answer
Slightly higher amps than bare steel for the same result — then set travel speed by watching the pool, not the clock: a consistent-width bead with proper wetting at the toes is the target on galvanised steel.
Starting numbers
Take the standard thickness-based amperage for steel and apply the material adjustment above. On galvanised steel, test coupons are not optional — set two or three parameter sets on scrap and pick the bead that wets in without undermining the edges.