In this study, sheet steels for automobile body panels were hot-dip galvanized using a commercial hot-dip simulator. The effects of the pot Al content, pot temperature, strip entry temperature and dipping time on the Al content and microstructure of GI coating were investigated. Analyses of Taguchi methods revealed that the pot Al content and dipping time markedly influenced the Al content in the coating. Increasing the pot Al content promoted the formation of FexAly inhibition layer. However, the effect of FexAly phases on inhibiting the growth of FeZn phases strongly depended on the dipping time and strip entry temperature. For the steel processed at 490 deg C entry temperature, 500 deg C pot temperature, the formation of FeZn phases was not completely inhibited after 1 s of hot dipping in the Zn pot containing 0.2 wt percent Al. The open circuit potential (OCP) of GI steel with a FexAly inhibition layer exhibited a spike right before it reached a constant value corresponding to the dissolution of the steel substrate.
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