A STUDY OF DRY COATING PROCESS

Dry zinc coating processes similar to the shot pinning was studied in the aspects of environmentally benign process to substitute traditional wet type phosphate coating of the work-piece, which is for protection from the deterioration of the surface quality and the shortening of the lifetime of the die during cold extrusion. Experiment and simulation on the collision and coating process of the zinc coated steel balls onto the steel target was performed. Coating patterns on the target and damage of the zinc shell of the ball with respect to the colliding speed were observed during the experiment. Explicit finite element analysis showed the deformation and the fracture of the zinc shell were similar to the experimental results even though the adhesion of the zinc layer onto the work-piece could not be expressed directly. The optimal velocity of the balls was obtained considering effective zinc coating and maximum lifetime of the ball.