Effects of Environmental Factors on Pitting Corrosion Behavior of 1.4539 Stainless Steel

The effects of temperature, load and Cl^- concentration on pitting corrosion behavior of 1.4539 stainless steel were investigated by immersion corrosion test and electrochemical test. The results show that the 1.4539 stainless steel had good pitting corrosion resistance when the temperature of medium was less than 50 ℃. But when the temperature was above 50 ℃, the pitting corrosion potential decreased rapidly with the increase of temperature. When the tensile stress generated by applied load was higher than 0.54σ_s, the passivation zone of the material disappeared, the anodic curves changed to active dissolution, and the anodic current density increased rapidly with the increase of tensile stress. In the electrochemical system coupled with Cl^- content and tensile load, when the mass fraction of NaCl was no more than 5%, tensile load could significantly increase the Cl^- corrosion sensitivity of the 1.4539 stainless steel; when the mass fraction of NaCl was no less than 7%, the effect of tensile load on the Cl^- corrosion sensitivity of the 1.4539 stainless steel reduced.