A quantitative The problem of edge overcoating developed near the edge of the steel strip is studied quantitatively in the gas wiping process of continuous hot-dip galvanizing. It has been assumed that the edge overcoating occurs due to the reduced impact pressure of wiping gas on the strip edge and it is one of detrimental problems to the quality of coating products. In order to analyse the edge overcoating problem numerically, three-dimensional unsteady flows due to the gas wiping are calculated by using a commercial code, STAR-CD. The standard κ-ε model is used as a turbulence model. The 1D code for calculation of coating thickness is constructed by using the continuity and Navier-Stokes equations. The calculation results have shown good agreement with measurements of edge overcoating thickness, taken from galvanizing line trials. Therefore, it is confirmed that the major cause of edge overcoating is the reduced impact pressure of wiping gas on the strip surface.
