PROCESS FOR COATING A HOT- OR COLD-ROLLED STEEL STRIP CONTAINING 6 - 30% BY WEIGHT OF MN WITH A METALLIC PROTECTIVE LAYER

摘要

The present invention relates to a process for coating a hot- or cold-rolled steel strip containing 6 - 30% by weight of Mn with a metallic protective layer, in particular a zinc-based protective layer, in which the steel strip to be coated is heat treated at a heat treatment temperature of 800 - 1100°C under a heat treatment atmosphere containing nitrogen, water and hydrogen and is subsequently subjected to melt dip coating. The process of the invention enables steel sheets having high manganese contests to be melt dip coated in an inexpensive way. This is achieved by the ratio %H₂O/%H₂ of the water content %H₂0 to the hydrogen content %H₂ of the heat treatment atmosphere being set as a function of the respective heat treatment temperature T_G as follows: %H₂O/%H₂ = 8·10^-15 ·T_G