The pickling process is mainly to remove the iron rust on the surface of steel components and to melt zinc when galvanized.React with steel matrix to form galvanized layer. If the surface is not clean and the rust stain is not removed,When the workpiece enters molten zinc solution, the rust stain prevents the surface of the steel matrix from reacting with zinc to form zinc-ferroalloyLayer, resulting in leakage plating point (block), leading to rework replating; Single acid solution in new acid or immersionExcessive corrosion and hydrogen dissociation will occur on the surface of components over a long period of time, the mud slag with strong properties is difficult to be washed off on the surface of steel, so it can not be plated with solvent, hydrogen dissociation phenomenonThe hydrogen stored in the steel substrate is released by heat release in the zinc solution, which damages the crystallization of the galvanized layer.Gray spot, resulting in the workpiece missing plating rework or even scrap. The washing process is mainly to wash off the worksheet.Surface iron salt and impurities, reduce the zinc ash, zinc slag formation.
(1) distinguish the corrosion degree of workpiece from acid cleaningThe workpieces entering the hot dip galvanizing production line, including the hot dip galvanized workpieces and precast parts, are storedDuring the period of release, serious rust should be prevented. For steel parts that have been seriously corroded and generally mildThe corroded steel parts should be pickling separately. The acid washing time should be different depending on the degree of corrosion.To prevent slightly corroded steel parts from pickling during pickling to avoid hydrogen dissection and steelPitting appeared on the surface. Methods for workpieces with severe corrosion: 1. Physical and mechanical rust removal method,After a certain period of pickling, a small iron shovel is used to remove some of the non-derusting layers: 2"Lift and place for 10-24 hours to allow the workpiece to generate new rust, so that the rust removal effect is good; So, theta is medium,The acid will be soaked in the concentration of acid for a certain period of time.The scale. In order to avoid the workpiece overlap pickling not clean, in the workpiece pickling forward line loading basket, diagonalSteel workpieces are separated and stacked or put into special basket tools to carry out pickling of steel workpieces by hanging cageThe pickling speed is fast and good.