Tempering Behavior of Novel Low-Alloy High-Strength Steel

The effect of tempering on the mechanical properties, structure, and dispersion secondary phase particles is studied in 0.4%C-2%Si-1%Cr-1%Mo-VNb steel. This steel austenitized at 900 °C with subsequent water quenching exhibits a yield stress 1445 MPa lath martensite structure MX ~40 nm located matrix boundary M6C carbides ~210 nm. Tempering temperature interval 200–400 provides 1625 due to precipitation ε-carbide cementite within laths. decreases 1415 1310 after 500 650 °C, respectively, replacement by M23C6 carbide. A Charpy V-notch impact energy ~12 J/cm2 almost independent from temperatures up 400 increases ~33 decreased stresses increased plasticity.