Method and apparatus for coating ferrous-metal strands

摘要

In hot-dip coating a ferrous metal strand with an aluminium/zinc alloy or like metallic coating medium, the strand (3) is traversed from a furnace to a "galvanising" bath (6), through a duct (4) terminating in a hood (5) which dips into the bath (6). While the strand (3) is in the duct (4) and the hood (5) it is subjected to a gaseous reducing environment. The gas consists of N2 and may have as much as 15% of hydrogen in it. The temperature of the gas may be ambient temperature. The pressure of the gas is just great enough to establish a plenum in the duct (4) so that it may diffuse into the hood (5) and there be quiescent and maintained substantially constant in quantity and composition.