Corrosion Behavior of Cu Containing Anti-Corrosion Plastic Mold Steel in Dilute Hydrochloric Acid Solution

The corrosion behavior of copper-containing corrosion resistant plastic mold steel in 0.5%（mass fraction）dilute hydrochloric acid solution was investigated by using SEM, EDS and electrochemical measurements. The results indicate under different tempering conditions at 250 ℃ and 600 ℃, the corrosion rates of 4Cr13Cu exposed in dilute acid solution for 24 h are 2.62 mm·a^-1 and 8.22 mm·a^-1, respectively, while the corrosion rates of 4Cr13 are 15.86 mm·a^-1 and 18.03 mm·a^-1,which indicates that the corrosion resistance of 4Cr13Cu is better than that of 4Cr13. The polarization curves show that4Cr13Cu has higher hydrogen overpotential compared with 4Cr13, which suppresses cathodic hydrogen evolution reaction.The enrichment of copper in the corrosion products of 4Cr13Cu can weaken the galvanic corrosion effect caused by the undissolved carbides in cathode and anode matrix, which can reduce the corrosion tendency of 4Cr13Cu in dilute acidic solution environment.