Analysis on Defects on Surface of Hot-dip Galvanized Automobile Steels Caused by Air Knife Splashing and Countermeasures
Aiming at the bright spot defects and white spot defects on the surface of hot-dip galvanized automobile steel sheets,their microstructures and structural constituents were analyzed by scanning electron microscopy (SEM). The analytical results showed that the above defects be-longed to zinc particle defects and zinc skin defects,which were caused by air knife splashing. Therefore,after taking such countermeasures as stably controlling the production line speed,opti-mizing the process parameters including air knife pressures,air knife heights and air knife angles,and strictly managing the maintenance and inspection for the air knife,the downgrade rate of zinc particle defects caused by air knife splashing was decreased to 0.11％ from 0.23％,the downgrade rate of zinc skin defects was reduced to 0.06％ from 0.11％,which met the requirements on the surface quality of automobile steel sheets asked by users.
万方数据
维普
