Effects of C and Si Content on Corrosion Behavior of Wheel Steel

Corrosion behavior of wheel steel with different C and Si contents was investigated using alternate immersion test and electrochemical test in 3.5% (mass fraction) NaCl solution. The corrosion rate was calculated based on the weight loss measurement. The surface morphology and cross section of specimens corroded for different times were observed. The surface roughness and the size of corrosion pits on the surface of specimens corroded for different times were measured using optical metrology. The results show that the corrosion rate increased with the increase of C content and with the decrease of Si content. The free corrosion potential and charge transfer resistance increased with the increase of Si content, resulting in the improvement of corrosion resistance of wheel steel. Corrosion pits existed on the surface of specimens corroded for 3 days, and the surface roughness and the size of corrosion pits increased with the prolongation of corrosion time. Corrosion pits can destroy the integrity of wheel surface and make stress concentrate on the bottom of pits, which are harmful to the operation safety of the wheels.