The Damage Assessment Of Q345R Under The Synergistic Effect Of High Stress And Corrosive Environment

Special equipments are widely used in the production and living areas, on many occasions the materials in use are not only subject to environmental or corrosive medium, but also to bear the high stress of the load. Therefore, to ensure the safety of special equipments, we must fully consider the corrosion and load synergy of materials, and to study its behavior under the synergistic effect of corrosion and load damage.(1)For the forms and the mechanism of the synergy of media and stress, the author proposed a new form of injury of the medium and stress:the synergistic damage of the plastic damage and corrosion damage. Such injury is different from existing corrosion fatigue and wear corrosion, it’s a new form of synergy of media and stress.(2) For this new form of injury, based on the basis of the damage theory of thermodynamics, the author studied the injury thermodynamic relations including electrochemical energy. Through the introduction of energy dissipation in the process of corrosion damage, we established the corrosion current and quality loss damage, in order to bulid the foundation to carry out the research of corrosion and stress synergy mechanism..(3) For the Q345R materials’ corrosion mechanism and behavior in the typical corrosion environment of acidic salt spray, through salt spray test on whether the load and whether the defect three Q345R accelerated corrosion test, we studied the corrosion degradation of material properties as well as the load and environment synergistic acceleration effect on the materials.(4) For the Q345R materials’ mechanical-chemical effects and chemical-mechanical effects in corrosion environment, we measured the Q345R specimens’ polarization curves and corrosion current density in different stress levels using the electrochemical workstation, and proved that the level of stress within the plastic range have obvious effects on the corrosion rate.