The conventional double-variety production line of alloyed galvanized sheet products and pure zinc-galvanized products is a two-pot mode, that is, a dedicated zinc pot is used for the alloyed galvanized sheet product and the pure zinc plated product, respectively. In the production process of alloyed galvanized sheet products, the temperature of the strip into the zinc pot is about 460-500 °C, the temperature of the molten zinc pot is about 455 °C, the Al content of the zinc liquid is low (less than 0.15%), and the surface of the strip cannot be formed. The effective Fe2Al5 barrier layer, after the steel enters the molten zinc pot, the surface iron is inevitably dissolved in the zinc liquid in a large amount, causing the iron content in the zinc pot to rise sharply to about 0.04%, and the iron which is supersaturated in the zinc liquid will be the zinc in the zinc solution reacts to form a large amount of zinc-iron compound which sinks to the bottom of the pan to form a bottom slag. After the production of the alloyed galvanized sheet product is completed, the zinc pot is switched to produce the pure zinc hot-dip galvanized product. At this time, the zinc liquid component in the molten zinc pot needs to be adjusted to react the bottom slag with the aluminum in the zinc liquid to form dross (melting zinc). The pot is replaced by adding a high-aluminum ingot to the zinc-iron compound bottom slag in the zinc pot to form a molten zinc-aluminum compound to form a scum, thereby replacing the bottom slag in the molten zinc pot.
The method for quickly removing the bottom slag in the molten zinc pot is specifically: after the production of the alloyed galvanized sheet is completed, a zinc-aluminum alloy ingot with an aluminum content of 8% is added to the zinc pot to increase the aluminum content of the zinc liquid in the zinc pot. To 0.38% to 0.5%, the aluminum content in the zinc solution in the zinc pot is detected in real time during the addition of the zinc-aluminum alloy ingot; when the aluminum content reaches 0.38% to 0.5%, the addition of the zinc-aluminum alloy ingot with the aluminum content of 8% is stopped. Adding a zinc-aluminum alloy ingot with an aluminum content of 0.575% to the molten zinc pot, when the iron content of the zinc liquid in the zinc pot is stabilized within 0.01%, the bottom slag of the molten zinc pot is removed. The patented technology of the invention can quickly replace the bottom slag formed in the production process of the alloyed galvanized sheet by the single zinc pot production line, reduce the iron content in the zinc liquid, inhibit the generation of zinc particles, and reduce the probability of occurrence of zinc particle defects.
Eternal Bliss Alloy Casting & Forging Co, Ltd.
Tel：0086-130 930 23772