Effects of various double-quenching treatments on the microstructure and corrosion properties of D2 tool steel

The purpose of this paper is to study the effects of the various double-quenching treatments on the microstructure and corrosion properties of D2 tool steel. The percentage and the size of carbides and the phase types were parameters that affected the properties of various specimens. Both optical and field emission scanning electron microscopy were used to study the specimen microstructure. Moreover, the Tafel polarization, electrochemical impedance spectroscopy, and weight loss tests were evaluated to investigate the corrosion behavior. The obtained results showed that the martensite and tempered martensite phases exhibited the highest and lowest corrosion rates in 0.6 M NaCl solution, respectively. A Higher percentage of (Cr, Fe)7C3 carbides with a higher size also caused an increase in the corrosion resistance up to 91.2%. The lowest corrosion rate after 96 h was also related to tempered specimens. •New various double-quenching treatments were done on D2 tool steel.•The corrosion rate decreased by about 100% when specImens were tempered at 500 °C.•A high size of carbides in tempered martensite increased the corrosion resistance.