Study of the Passive film on Hot -dip Zn -Al Galvanizing Extra deep Drawing Steel

摘要

In order to prevent the deformation area of the hot -dip Zn -Al Galvanizing extra deep drawing steel blackening during the drawing process, the microstructure and composition of the blackening area was researched by SEM and EDS. The blackening during the drawing process was caused by Zn -Al coating corrosion after the damage of passive film. And the effective measures that the surface passive film on Zn -Al coating had self-lubrication and the friction factor of the surface below 0.2 to prevent the blackened was determined, then a self-lubricating hot -dip Zn -Al Galvanizing extra deep drawing steel was developed. According to the results of research on reperformance and application of the products, self-lubricating hot -dip Zn -Al Galvanizing extra deep drawing steel has excellent drawing formability, the surface of deformation zone of this steel sheet had no obvious scratch, blackening and dezincification, and the passive film also has good performances on corrosion resistance, fingerprint resistance, water resistance and resistance to blackening. So it can meet the application stardards for home appliance.