Corrosion protection of steel products The pretreatment line combines the preheating, shot blasting, painting and drying of workpieces (such as steel plates and profiles) in one automatic production line. Pretreatment lines are ideal when there are lengthy manufacturing or storage times between blasting and coating. In order to prevent re-rusting, timely spraying of primer can guarantee corrosion resistance for several weeks. The width of the plate can reach 5500mm, and the conveying speed of the roller table is from 1.0-6.0 m/min.