Effects of Fluid Flow Rate and Stress Amplitude on the Initiation and Growth Behavior of Corrosion Pits on an Annealed Carbon Steel

摘要

In order to clarify the effects of the fluid flow rate and stress amplitude on the initiation and growth behavior of corrosion pits, round, smooth specimens were rotated at various speeds in sodium chloride aqueous solution. The results are summarized as follows: (1) The pit growth behavior was adequately predicted by Eq. (1), regardless of the fluid flow rated and stress amplitudes. (2) The pit initiation time decreases with an increase in the fluid flow rate and stress amplitudes. (3) For small pits whose sizes are about 0.03mm, the pit growth rates increase with an increase in the fluid flow rate, while the growth rates for pits above 0.08mm are independent of the fluid flow rate and smaller than those of 0.03 mm. The pit growth rates in the case of 100 MPa are 5～10 times larger than those of the nonstressing condition.