Continuous zinc coating appts. for coating metal strip - comprises melt alloy bath covered with hood having hydrogen, steam and inert gas atmos. and control system

摘要

In a surface treatment plant for continuous coating of strip with Zn-25-70wt.% coatings, the strip is passed through a protective hood into a molten alloy bath in which an atmos. of H2, steam, and an inert gas avoids formation of metal vapour. A data processing system is provided for optimisation of surface condition and redn. of metal lost via the gas phase, according to criteria of a) self-checking closed system, b) set points of protective gas dew point and permissible variation, known delay periods of measuring and control systems, water reservoir temp, min. and max. temp. are read in . Actual values of dew point and water reservoir temp., strip and melt temp. strip width and thickness are read in . Surface throughput and dew pt. variation are calculated. ADVANTAGE - Uniform coating quality is obtd.