Hot dip coating employing a plug of chilled coating metal

A hot dip coating system comprises a bath of molten coating metal contained in a vessel having a strip passage opening located below the top surface of the bath. A metal strip is directed along a path extending through the strip passage opening and through the bath of molten coating metal, to coat the strip. A plug composed of solidified coating metal surrounds the strip downstream of the strip passage opening and is substantially stationary relative to the moving strip. The plug prevents escape of molten coating metal from the bath through the strip passage opening while permitting the strip to move along its path. Expedients are provided to chill the coating metal downstream of the strip passage opening to form and maintain the plug and to heat that part of the molten metal coating bath which is immediately downstream of the plug.