Effect of precipitation strengthening in low alloyed Mn–Ni cast steels

The influence of modification and heat treatment on the properties of low alloyed C–Mn 1.4-V cast steels has been investigated. A new type of cast steel with a yield strength above 850 MPa and elongation higher than 8% obtained in stepped samples with 20–75 mm wall thickness by microalloying, optimal tempering and control of ferrite volume in the matrix has been developed. Yield strength and toughness were controlled by the precipitation of carbonitrides in substantially ferritic microstructure. The morphology of these precipitates was controlled by the cooling rate during crystallization of the alloy.