Corrosion Behavior of DP590 Steel in Vapor of Three Salt Solutions

Corrosion tests were carried out on high-strength steel DP590 for automobiles in three kinds of salt solution vapor of CaCl₂、MgCl₂ and NaCl, and the corrosion behavior of DP590 steel was studied by observation of macro and micro morphology, weight gain method and electrochemical testing. The results show that red rust with different degrees appeared on the surface of DP590 steel corroded in the salt solution vapor for 40 h. As the salt concentration increased, the corrosion mass gain of DP590 steel increased. The corrosion products on the surface of the steel were Fe₃O₄ mainly, and a small amount of Fe₂O₃, FeO(OH). With the increase of salt concentration, the free corrosion potential of DP590 steel shifted negatively, and the corrosion current density increased, indicating the decrease of corrosion resistance of DP590 steel.