Study of the Growth Rate of Rust Spots on Steel Surface Under the Effect of Low-Temperature Heating and Cooling in Different Media

Abstract

This research investigates the corrosion rate on the surface of steel samples exposed to low-temperature heating and cooled in two different media (freshwater and natural seawater).

The surface of steel samples were first cleaned with a steel brush and then heated to a temperature of 125℃. They were then immediately quenched in basins containing either freshwater or natural seawater for 1 minute. After cooling, the samples were kept in laboratory conditions to monitor surface changes using visual inspection and a microscope. 

After Microscopic images were taken over specific time periods, the change in the area of a specific rust spot on the surface of each steel sample was calculated over time using MATLAB software, in order to determine the corrosion propagation rate.

The results showed an increase in the rate of growth of rust spots (corrosion rate) and a change in the color of rust spots formed on the steel surfaces that were heated and cooled in seawater, compared to those cooled in freshwater.