Experimental investigation on corrosion behaviour of Fe‐C‐Cr P/M alloy steels

Abstract

Experimental investigation is under taken in the present work to understand the corrosion mechanism of sinter‐forged Fe‐0.5%C, Fe‐0.5%C‐1%Cr and Fe‐0.5%C‐2%Cr low alloy steels. Aqueous immersion and electrochemical corrosion tests were conducted on the forged alloys using 18% HCl acid solution for various timings to simulate the pickling corrosion. Weight loss measurement was made on the corroded specimens. Corrosion rate is found to decrease drastically with increase in percentage theoretical density irrespective of the alloy compositions. It is found from the results that addition of Cr enhances the corrosion resistance of the alloy steels. The enhanced hardness of the densified alloy steel specimen improves the corrosive resistance of the alloy steel. Corrosion rates were determined using Tafel plots in the case of electrochemical corrosion. Microstructure of the forged alloys revealed the presence of numerous fine rounded pores both within the grains and along the grain boundaries. SEM and XRD were taken for all the compositions and correlated with the corrosion behaviour of the alloy steels.