Dipl.-Ing. Dr.mont. Susanne Koch
Polyolefin coatings enhance the corrosion resistance of galvanized steel strips in aggressive environments like abrasive wear, highly concentrated acids, salts or bases. Applications, for example in the field of road construction (Figure 1), benefit from the achieved long-term resistance under extreme conditions. The rebated joints (Figure 2) are sensitive points due to the high degree of deformation. Observed defects of the polymer coating are: • cracks • delamination • coating thickness minimization The objective is to quantify the impact of the following process parameters: • contact pressure p • steel strip temperature T • steel strip thickness d • surface roughness Rz • primer application mg • primer composition c Terms and conditions for improved coating adhesion are identified with Design of Experiments (Modde®7.0). The testing facility comprises a computer for temperature recording, a resistance furnace for strip heating to lamination temperature, a rolling mill and a water basin for quenching the coated strip. The coating adhesion is evaluated via peel test.
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