Four Roles of Surface Finishing of Galvanized Steel
(1) Improve the surface flatness of galvanized steel sheet. After smoothing, the flatness of the galvanized steel sheet is improved to a certain extent, and the wave shape of the galvanized steel sheet is partially eliminated. At the same time, the surface slag particles or other uneven points can be flattened to make the surface smooth and flat.
(2) Adjust the surface roughness of the galvanized steel sheet. By controlling the roughness of the surface of the work roll of the light finishing machine, the original uneven roughness of the surface of the galvanized steel sheet can be unified to a certain range. This can improve product paintability and lubricity during processing.
(3) Improve the surface color of galvanized steel sheet. For small zinc flower and non-zinc flower products, the surface of the galvanized steel plate can be more uniform and uniform through smoothing. For some private enterprises to use large zinc flower products as color-coated substrates, the zinc flower bumps and different glossiness formed by large zinc flower crystals can be flattened and unified, making the zinc flower blurred and conducive Cover zinc flowers during painting.
(4) Improve the workability of galvanized steel sheet. Through the finishing, the yield platform of the galvanized steel sheet can be disappeared or inconspicuous, and the metal slip line can be prevented from being generated in the subsequent processing.
0.6mm galvanized sheet
缺陷 Surface defects of galvanized steel
The main defects of galvanized steel plate are: shedding, scratches, passivation spots, zinc particles, thick edges, air knife streaks, air knife scratches, exposed steel, inclusions, mechanical damage, poor steel base performance, wave edges, and curl , Size mismatch, embossing, zinc layer thickness mismatch, roll printing, etc.
The main reasons for the zinc layer to fall off are: surface oxidation, silicon compounds, cold rolled emulsions are too dirty, the NOF stage oxidation atmosphere and protective gas dew point are too high, the air-fuel ratio is unreasonable, the hydrogen flow is low, the furnace has oxygen infiltration, strip The temperature of the pot is too low, the furnace pressure in the RWP section is low and the furnace door is suctioned, the temperature in the NOF section is low, the oil is not evaporated, the aluminum content in the zinc pot is too low, the unit speed is too fast, the reduction is insufficient, and the zinc stays The time is too short and the coating is too thick.