Corrosion Behavior of P/M Plain Carbon Steel under the Influence of Various Heat Treatment Processes

ABSTRACT The present research work focuses on the effects of heat treatment on corrosion behavior of sintered plain carbon steel (Fe-0.5%C). Investigation on corrosion mechanism has been carried out on three different heat-treated (annealing, normalizing, and hardening) powder metallurgy plain carbon steel specimens. Aqueous immersion and electrochemical pickling corrosion tests were conducted on the heat-treated specimens. It has been found that the heat treatments have enhanced the percentage of theoretical density as well as the hardness of the specimen compared with the as-sintered specimen. The corrosion resistance of the oil-quenched specimen was found to be higher than that of the other heat-treated specimens. Larger grains are observed in the case of as-sintered and annealed specimens, and more iron carbides are observed in the normalized and oil-quenched specimens. Intergranular and pitting types of corrosion have been observed in the scanning electron microscopy images of corroded specimens.