GAS KNIFE PROCESS FOR CONTROLLING HOT-DIP ALUMINUM COATINGS

摘要

A gas knife process for controlling the thickness profile of hot-dip aluminum coatings, employs a hybrid gas knife design incorporating both a "curved-lip" with a "bow-tie" orifice. This design, in combination with very close knife to strip distance at the strip edges, was found to provide desirable coating profiles. Best results are obtained with knife deflections of 5 DEG to 30 DEG below the horizontal while utilizing orifice pressures of 15 to 70 mm of Hg at line speeds of 20 to 150 m/min.