The influence of variable Manganese content (2.4−4.6 wt%), while keeping constant Silicon
(1.5 wt%) and Chromium (0.3 wt%) levels, and variable oxidation potential of the annealing
atmosphere on hot dip galvanizability was investigated. Surface oxides prior to hot dip
galvanizing were analyzed and coating quality assessed. The increasing oxidation potential
of the annealing atmosphere led to a transition from external to internal selective
oxidation of Mn, Si and Cr; their enrichment at the surface could be reduced and the
metallic iron at the surface was increased. Hot dip galvanizability could thus be obtained
up to 2.9%Mn. With increasing Mn content, the surface was covered by a rising amount of
Mn-oxides. By exceeding a critical amount of Manganese, reactivity in the Zinc bath was
deteriorated. This amount was found to be between 2.9 and 3.8 wt% for Si content of 1.5
wt%.