How do aluminum-containing and aluminum-free zinc melts differ in their corrosion effects on iron

When steel pipes are immersed in zinc for a short duration, the corrosion rate in aluminum-free galvanizing pots is approximately 7-9 times faster than that in aluminum-containing galvanizing pots. However, when the immersion time exceeds 8 minutes, the corrosion rate in aluminum-containing galvanizing pots becomes higher than that in aluminum-free pots. The former is beneficial for increasing production through rapid zinc immersion, while the latter has adverse effects on galvanizing pots. Therefore, in actual production using aluminum-added galvanizing pots, it is observed that the pits corroded into the steel plates of the galvanizing pots at the zinc liquid surface are deeper.