Effects of Cr-rich Carbide Dissolution on the Electrochemical Corrosion Resistance of Laser Shock Peened High Strength Low Alloy (HSLA) Steel
Y.W. Ju, C.Y. Wang, K.Y. Luo and J.Z. Lu
Laser shock peening (LSP) is considered an effective surface treatment technology to enhance the corrosion resistance of metallic materials. Herein the electrochemical corrosion behaviours and dual-phase microstructure changes of a high strength low alloy (HSLA) steel after LSP with a Nd:YAG laser were studied by surface morphological assessment, microstructural characterization and electrochemical corrosion tests. The results showed that charge transfer resistance was increased by 101.2% and corrosion current density was decreased by 45.7%, indicating that LSP can effectively improve the electrochemical corrosion performance of HSLA steel. In addition, LSP promoted the production of ultrafine grains as well as the complete dissolution of Cr-rich carbides, helping to enhance corrosion resistance.
Keywords: Nd:YAG laser, high strength low alloy (HSLA) steel, laser shock peening (LSP), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), phase, microstructure, corrosion