|JURČI Peter||STU, MtF v Trnave|
|Spoluautoři ZAHRADNÍK Juraj, SALABOVÁ Petra, PRIKNER Otakar|
The ledeburitic steel Vanadis 6 has been austenitized at the temperatures from the range 1000 – 1075 oC, nitrogen gas quenched and twice tempered at the temperatures 100 – 600 oC. Each tempering cycle was 2 h. One half of the samples, processed via any regime of heat treatment, have been subjected to sub-zero period realised at -196 oC/4 h. The effect of sub-zero processing on the tempering characteristics has been investigated and the results will be presented in the current paper. It has been found that the martensite after sub-zero processing differs from that of conventionally transformed in terms of substructure. The sub-zero processing induced a multiple reduction of the volume fraction of retained austenite. This makes a difference between as-tempered microstructure of sub-zero processed and no-sub-zero processed steel, which results in different as-tempered hardness and heat resistance.