The galvanization on the gi steel sheet surfaces makes the steel have a great corrosion resistance. Then the service life is very long. Therefore, it is widely used into many industries. But during the gi steel sheet production process, it maybe come accross many problems because the production process is not rigorous.
Black spot is one of the problems. From the years of production experience, CAMELSTEEL finds that the black spot will affect its subsequent processing of surface quality. If it is very serious, the steel will scrap. So people need to give the tips according to the causes.
1. When people do the spray, the outfall is not seal up well, some organic thing mingled with the spray will cause the black spot on the surface.
2. On the chemical cause, the zinc produced in the zinc layer will produce hydrate, and the exposure parts will have chemical reaction and the color is black.
3. The passivation liquid is swing on the board.
4. The place, where the black spot in on, is not protected carefully. And it is damaged by extruded and friction.
Zibo Camel Material Co., Ltd. was created in 2009 and focus on creating famous steel coil brand – CAMELSTEEL. We are professional manufacturer and trading company of steel coils. Our main products include prepainted galvanized steel coil, prepainted galvalume steel coil, galvanized steel coil , galvalume steel sheet and corrugated roofing sheet etc. .And they are widely applied in the area of building, household appliances, light industry and decoration etc. , both domestic and foreign markets. We adopt advanced production technology in produce process. And there are two color coated steel line, two galvanized line and one galvalume line.