Corrosion Behavior of Q355B Steel Bar in Simulated Soil Solution of Sichuan-Tibet Railway Area

The effects of different concentrations of sodium chloride, sodium sulfate, potassium nitrate and sodium carbonate solution in Sichuan-Tibet railway soil simulation solution and different test temperatures on the corrosion behavior of Q355B carbon steel were studied by polarization curves and electrochemical impedance spectroscopy. The results showed that when the addition of sodium chloride, sodium sulfate, potassium nitrate and sodium carbonate was less than 0.3%, the increase of anion and cation concentration had a slight effect on the corrosion of Q355B steel. When the addition of sodium chloride, sodium sulfate and potassium nitrate reached 1 mol/L, the corrosion severity of Q355B steel in the simulated solution with different solutions was sodium chloride, sodium sulfate and potassium nitrate in turn, and there was no obvious corrosion and pitting trace on the surface of Q355B steel, and the steel surface could maintain passivation state. In the simulated solution, the corrosion rate of Q355B steel increased gradually with the increase of temperature, and the corrosion rate of Q355B steel at 70 ℃ was about 2.2 times that at 15 ℃.