IMPROVEMENT OF CARBIDE MORPHOLOGY ANDMECHANICAL PROPERTIES OF Cr12MoV STEELS

Compared with conventional cast Cr12Mo V steel and forged Cr12Mo V steels, carbide morphology and properties of modified cast Cr12MoV steels were investigated by performing hardness test, impact test, fracture toughness test, fatigue crack propagation test, metallographic examination and quantitively metallographic analysis. The results indicate that the carbide morphology in modified cast steel is characterized by granular carbide uniformed- distributed, which is different from that of conventional cast steel, but similar to that of forged steel. The impact toughness of modified cast steel is distinctly increased to 12.75J/cm2 from 6.8J/cm2 in the conventional cast steel with networked carbide, because of carbide granulation. Furthermore, The fracture toughness and fatigue - cock-propagation threshoid of modified cast steel are not only higher than that of the conventional cast steel, but also higher than that of the forged steels.