Modelling of iron dissolution during hot dip galvanising of strip steel

During hot dip galvanising, the metal strip passes into the zinc bath at a temperature of similar to460degreesC. Iron from the strip dissolves into the bath during this operation, leading to problems such as dross formation and pickup. The model described in the present paper has been created in an attempt to quantify and understand the amount of iron dissolving from the strip as it passes through the zinc bath. This is a mathematical model based on well defined first principles of nucleation, growth and diffusion. The effect of process parameters on the amount of iron dissolving from the strip has been analysed, showing possible actions that may help to reduce the amount of dissolution.