One of the problem in galvanized strip production lines in the world, is edge-over coating. In hot-dip coating process, after passing the zinc pot and after small distance from melt surface, air jet flow contact to strip, and coating thickness is controled by various parameters such as, jet supply pressure, line speed, geometric distances and angle of jet flow. At first in this work, coating thickness was measured in galvaniziation laboratory experimentally in many production conditions in lateral direction, and then coating thickness was determined in center to edge of strip. Measuring was done by chemical and tool measurement. According to lack of information for pressure and shear stress distribution in Mobarakeh Steel corporation air knives, this work was validated with past work. Then jet flow of Mobarakeh Steel corporation air knives was simulated by commercial code and pressure and shear stress which was determined on moving strip. Then sensitive analysis was done to some of production parameters, such as line speed, supply jet pressure. Pressure and shear stress is as an initial condition to thickness code to determine coating thickness. To prevent edge over coating some devices was presented. At first these devices was simulated and then cylinder device by 10 mm diameter was tested in galvanizing by personnel assistance experimentally. Coating thickness was measured by tool measurement. Results of measuring display that edge over coating was reduced. Reducing of edge over coating cause to low consumption of zinc and usag of this strip in specification consumptions.
