Simulation experiments were conducted to identify the dominant factors that affect topdross generation in metal coating baths. From the experiments and the microstructuralanalyses of the top dross, it is proposed that top dross is generated through bath metalentrainment by the oxide film and subsequent drainage during holding. A new concept,taking into consideration the fresh area creation during the wiping process, is introducedand a mathematical model is developed to quantify dross generation in the metal coatingprocess. From the proposed mechanism, a new metric is developed to quantify top drossgeneration in the coating bath. The experimental results agree well with both theoreticalresults and production data of galvanising (GI) baths based on this metric.
