Electrochemical Polishing of Structural Alloyed Steels
The process of electrochemical polishing of structural alloyed steels of the grades St25H3M3NBTSA and St30KhNMFA in solutions based on phosphoric and sulfuric acids with various additives on a rotating disk electrode (VDE) was carried out at different speeds of rotation. Imitation of the hydrodynamic processing conditions in the flow electrolyte with the aid of VDE facilitates the process of smoothening of surface microrelief. Carrying out the process at room temperature does not allow to obtain a high quality of the treated surface, since the steel St25X3M3NBTSA and St30HN2MFA tends to be passivated. Increasing the temperature to 65-70°C facilitates the dissolution of passive films, and roughness value of Ra = 0.16 μm is obtained when the process in is performed the electrolyte containing chromic anhydride and 0.08 μm in a solution with triethanolamine. It has been shown that the use of electrolyte based on phosphoric and sulfuric acids with the addition of triethanolamine is preferable, since it is more environmentally friendly and gives better quality of the treated surface than the phosphoric sulfuric acid solution.