Analysis of suspected iron scale defects on surface of high-grade automobile outer panel

The suspected iron scale defects on the surface of high grade automobile outer panel affect the primary yield of the product. By means of SEM and EDS, the suspected iron scale defects on the surface of high grade automobile produced by Shougang Jingtang Company were studied. The results show that there are concave-convex points on the surface of the cold rolling roller in the production of high grade automobile outer plate. The main reasons for the suspected iron scale defects are the peeling-off of the coating on the rolls of the galvanizing furnace, the mould powder entrapment in steelmaking and hot-rolling descaling nozzles. In view of the above problems, effective measures such as strengthening the surface quality inspection of the rolls, improving the coating adhesion of the galvanizing furnace rolls, strengthening the protective casting, regularly checking and replacing the descaling nozzles to ensure the descaling pressure were taken in the process of producing high-grade automobile outer panel.