METHOD AND APPARATUS FOR MONITORING AND CONTROLLING THE QUALITY OF A GALVANNEALED COATING OF STEEL STRIP

摘要

A method and an apparatus for monitoring and controlling the quality of the galvannealed coating of steel strip immediately following the galvannealing step, wherein the hot galvanized coating of the steel strip produced by hot dipping is converted into FeZn phases by diffusion reactions through a thermal treatment in an annealing furnace at temperatures above the melting point of zinc. The measurement value used for the quality of the galvannealed coating of the steel strip is the visual appearance of the galvannealed coating recorded by a visual recording device in the form of measurement signals as the quality measurement value, wherein the measurement signals are processed by measurement technology and the resulting measurement values are used after conversion into control variables for the direct control of the annealing furnace.