Optimizing Surface Roughness to Improve Steel-rubber Adhesion Strength through Electro-cleaning Simulation

Abstract

In this study, we have simulated the electro-cleaning process considering the actual surface topography of steel sheet to determine the final topography and roughness of the steel surface (R_z, distance between the surface peak and the valley) after different duration of electro-cleaning. COMSOL Multi-Physics^® simulation module with moving mesh technique was used for the electro-cleaning simulation. The effect of applied current density (A/m²), electrolyte concentration (H₂SO₄, g/l) and temperature (°C) on the change in roughness (ΔR_z, µm) of steel surface was evaluated by the simulation. Simulation results show that the current density has the highest effect towards the change in roughness of steel surface. The change in roughness increases with increase in current density. The current density of 500–700 A/m² is required for appreciable electro-cleaning roughness in this study. An electrolyte concentration of 40–60 g/l would provide the maximum change in roughness for any fixed applied current density. The change in roughness also increases with increasing the electrolyte temperature. Lab scale experimentation showed good agreement with the simulated results. Finally, it was determined that 600 A/m² of applied current density and 4.75 µm of steel surface final roughness (R_z,f) would provide the maximum adhesion strength of 110 N between the steel and rubber.