The Study Of Electrochemical Behavior And Stress Corrosion Behavior Of316L Stainless Steel In Seawater Under Industrial Applications

316L stainless steel is chosen as the evaporimeter shell material of seawaterdesalination equipment of Low-temperature multi-effect distillation(LT-MED), and itis often corroded by industrial seawater. Electrochemical impedance spectroscopy,cyclic voltammetry, slow strain rate test, SEM observation of fracture surfaces wereused to study the corrosion behavior of316L stainless steel in industrial seawater. Thearticle analyses and evaluates corrosion resistance of temperature and solutionconcentration on the316L stainless steel. Based on the research contents, severalresults were required as follows:(1)Measuring electrochemical behavior of316L stainless steel in differentsolution and temperature. Test results of EIS show that: Rp of316L stainless steeldecreased with the temperature up, strengthening corrosion susceptibility;Polarization resistance is maximum in0.07times concentrated seawater and in1.5times concentrated seawater when zhe temperature is35℃,50℃,70℃; Polarizationresistance is minimum in0.36times concentrated seawater and in2timesconcentration of seawater; The pitting potential Ebof every solution decreased withthe temperature up by cyclic voltammetry method; While the temperature is invariable,solution resistance decreased with the concentration of the solution increasing, thenthe corrosion strengthen.(2) Measuring stress corrosion behavior of316L stainless steel in differentsolution and temperature, test results show that:316L stainless steel is relativelysensitive in0.07times concentration of seawater,1.5times concentrated seawater,2times concentrated seawater with the temperature up; Sensitivity of SCC firstlydecreased and then increased in0.36times concentration of seawater and nature seawater, and it is the lowest when the temperature is70℃; While the temperature isinvariable, elongation and maximum tensile strength decreased with the concentrationof the solution increasing by the experiment SSRT, then the sensitivity of SCCincreased. Results of SEM show that: in the same solution, micro fracturemorphology developd from ductile fracture to brittle fracture with the temperature up;In the same temperature, the sensitivity of SCC increased observing micro fracturemorphology with the concentration of the solution increasing.