The effect of silicon and vanadium alloying on the microstructure of air cooled forged HSLA steels

The paper presents comparison of results of microstructure investigations of HSLA steels: 38MnSi6 and SiV-steel. The main objective of this investigation has been to find the influence of the concentration of silicon increased to 1.26% and vanadium to 0.16% on the microstructure of SiV-steel in comparison to 38MnSi6. It has been found that SiV-steel represents higher volume fraction of proeutectoid ferrite, which is more evenly distributed in the structure, with finer prior austenite grain size. Higher concentration of vanadium and nitrogen characteristic of SiV-steel results in non-random dispersion of V(CN) precipitations. It has also been observed that microhardness of the proeutectoid ferrite, characteristic for SiV-steel, is about 70HV0.2 higher than in 38MnSi6 steel.