| Galvalume (GL) steel sheets, which have superior corrosion resistance, oxidation resistance and weldability compared with hot galvanized (GI) steel sheets, are widely used in construction, house electrical appliance, automobile and electricity instrument industries. A GL production line is being built in Cold Roll Plant of Meishan Iron & Steel Corporation (Mei-Steel). There is a great demand for the technique of GL production because Mei-Steel is short of experience in GL production.In this paper, the equipment status of GL line in Cold Roll Plant of Mei-Steel was analyzed, including uncoiler, entry shear, welder, entry looper, cleaning section, furnace section, zinc pot, air knife system, cooling section, sink pass mill, tension leveler, passivating or fingerprint processing, delivery looper, inspection, oiler, delivery shear, tension reel and so on. Problem which is possible on GL line of Mei-Steel is analysed, such as galvanizding, annealing furnace, air vapor cooling, post treatment, and the scheme to solve the above problem is offered. The main results are as follows:Thermocouple sheaths to measure the zinc pot temperature are improved, which prolongs the life of thermocouple sheaths form 50 hours in the original design to 30 days. Based on the analysis on reason to form cadamia and its effect factors, a technique for controlling cadamia to improve the surface quality of steel strip is offered.The technical parameter of annealing furnace is vetified, and the parameters to satisfy the technical demand are obtained.After some tests, type 4 nozzle is determined to use to the air vapor cooling system, which depress the atomizing height from 450mm to 300mm, and make atomization uniformity.Effect of chemical post treatment liquid temperature and post treatment time as well as baking temperature on the quality of steel strip is examined, and roller coat equitment is reconstructed.
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