Abstract
A systematic study on austenitizing behavior and mechanical properties of martensite steel 40CrNi2Si2MoVA has been made in this work. The effect of austenitizing temperature on Rockwell-C hardness and mechanical properties were measured and correlated with the microstructural features measured by scanning electron microscopy and transmission electron microscopy. The grain size grew larger with martensite laths coarsened and the carbide precipitates measured by X-ray diffraction were found to dissolve gradually by raising the austenitizing temperature. Rockwell-C hardness values of samples quenched from different austenitizing temperatures indicated that the solid solution hardening behavior became weaker. Tensile tests and impact tests showed that the strength decreased while the impact toughness improved obviously with increasing the austenitizing temperature from 870 to 980 °C. The fracture mode was changed from brittle fracture to ductile fracture with increasing austenitizing temperature.