engleski

Corrosion behaviour of tempered 42CrMo4 steel

Low-alloy 42CrMo4 steel (AISI 4140) is a medium carbon steel, commonly used as a quenched and tempered steel. Because of its good mechanical properties, high tensile strength and toughness, 42CrMo4 is one of the widely used and investigated steels. To increase ductility even more, in addition to standard quenching and tempering, the steel is often hardened by double quenching and tempering and austempering. The aim of this paper was to investigate the corrosion behaviour of 42CrMo4 steel after quenching and tempering, double quenching and tempering and austempering. For this purpose, microstructural characterization and electrochemical investigation after different hardening processes were performed. The microstructure of the specimens was observed using optical microscopy and scanning electron microscopy. Open circuit potential and potentiodynamic polarization measurements of the tempered specimens were carried out using a computer- controlled potentiostat with a three- electrode set- up in 0.6 M NaCl naturally aerated solution. It was concluded that applied heat treatment processes increase the corrosion resistance of the 42CrMo4 steel in comparison to normalized steel. In comparison to quenched and tempered steel, double quenching and tempering, as well as austempering, do not significantly change the corrosion resistance of the steel.

quenching ; tempering ; characterization ; corrosion

nije evidentirano