ĎURICA, Juraj – PTAČINOVÁ, Jana – DOMÁNKOVÁ, Mária – ČAPLOVIČ, Ľubomír – ČAPLOVIČOVÁ, Mária – HRUŠOVSKÁ, Linda – MALOVCOVÁ, Veronika – JURČI, Peter
In Vacuum. Vol. 170, (2019)
The microstructure of Vanadis 6 ledeburitic steel subjected to sub-zero treatments at −140 °C for different durations followed by various tempering regimes was investigated. The obtained results infer that: i) retained austenite amount is fivefold reduced by this treatment, and compressive stresses higher than 1500 MPa are generated in this phase, ii) martensite is refined due to SZT, and it contains enhanced number of crystal defects, iii) great number of “extra” cementitic carbides is formed during the sub-zero period; this number is higher than what is achieved by sub-zero treatments at −196 °C, iv) the number of “extra” carbides decreases with tempering, however, it remains higher than after in both the conventionally quenched and sub-zero treated at −196 °C steel, v) sub-zero treatments at −140 °C modify the precipitation behaviour substantially; coherent nano-sized ε-carbides and cementite were found already prior tempering the steel, and besides the cementite also M7C3 phase was detected after tempering treatment.