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 annealingatmosphere on hot dip galvanizability was investigated. Surface oxides prior to hot dipgalvanizing were analyzed and coating quality assessed. The increasing oxidation potentialof the annealing atmosphere led to a transition from external to internal selectiveoxidation of Mn, Si and Cr; their enrichment at the surface could be reduced and themetallic iron at the surface was increased. Hot dip galvanizability could thus be obtainedup to 2.9%Mn. With increasing Mn content, the surface was covered by a rising amount ofMn-oxides. By exceeding a critical amount of Manganese, reactivity in the Zinc bath wasdeteriorated. This amount was found to be between 2.9 and 3.8 wt% for Si content of 1.5wt%.
