| The staircase test block with 20, 45 and 75 mm wall thickness were performed on low alloyed Mn-Ni cast steels microalloyed by V or V + Nb additions. Precipitations of carbonitrides in these alloys are related to the different cooling rate and segregation during solidification process. The effects of V + Nb nanoparticles and heat treatments increased yield strength up to 850-950 MPa at the elongation above 8-10%. Particle size changes from 10 nm (in thin sections) to 60 nm (in 60-75mm wall thickness) and depends on the cooling rates (0.15-0.9 °C/s) and the process of microalloying. |
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