Precipitation characteristics during isothermal γ to α transformation and resultant hardness in low carbon vanadium–titanium bearing steel

Abstract

The effects of isothermal holding time on precipitation behaviour and resultant hardness were investigated in detail. Of particular note, with prolonged isothermal holding time at 650, 700 and 750° C, the hardness peak moves to a higher value, nearly remains unchanged, and to a lower value, respectively. It has been demonstrated that the nanometer–sized particles can nucleate at migrating γ/α interface for both rapid or slow transformation kinetics, and the changes in hardness are mainly related to precipitation behaviour. Regardless of isothermal holding time, the hardness increases as the transformation temperature decreases due to particle size and particle spacing refinement.