Effect of tempering temperature and grain refinement induced by severe shot peening on the corrosion behavior of a low alloy steel

Abstract

In this study, the effect of tempering temperature on the corrosion behavior of a low carbon steel (F1272) was analyzed by means of electrochemical tests: linear polarization resistance, potentyodinamic polarization and electrochemical impedance spectroscopy (EIS) in freely aerated 3.5% NaCl solution, at room temperature. The results show that corrosion resistance of the steel increases with elevating tempering temperature from 200 to 500 °C and finally, to 680 °C. Additionally, a severe shot peening (SSP) treatment was applied in the sample with the best corrosion behavior (TT680), in order to modify the grain structure. Results evidence that corrosion resistance of the TT680 sample decreases after the applied SSP treatment (10A and 5000% coverage). Corrosion behavior is discussed through the different microstructural singularities induced both the heat treatments and the SSP.