The corrosion behavior of X65 steel in a flowing solution

摘要

A device was developed to simulate the flowing aqueous medium in pipelines. This new sinulating method allowed normal electrodes or any specimens with a flat working surface area to be installed or removed directly any time during experiment. Meanwhile, many other monitoring techniuqes may also be simply used together witht the electrode in the device. By weight loss analysis, electro-chemistry test and surface investigation after the immersion in the flowing NaCl solution, the corrosion behavior of X65 pipe line steel was studied. The results showed that the steel had a varying corrosion rate, increasing at first and then decreasing with the increase of flow velocity, exhibiting a peak on the corrosion rate -flow velocity curve. This confirmed that there was a critical flow velocity for X65 in acqueous flow [1]. At the low flow velocity range, oxygen diffusion in the liquid should be controlling the corrosion process. When the flow velocity exceeded the critical flow velocity, corrosion mechanism might change.