Effects of Deformation Strains and Annealing Temperatures on Mechanical Properties of Martensitic Steels

The effects of deformation strains and annealing temperatures on microstructures and mechanical properties of martensitic steels were examined. The amount of cold deformation was changed as 30%, 50% and 60%, and annealing temperatures varied from 500°C to 600°C. In samples cold rolled 30%, the dominant microstructure for an annealing at 500°C was dislocation substructures with uniformly distributed rod-shaped carbide particles. For an annealing at 600°C, the microstructure consisted of equiaxed ultrafine grains, spherical carbide particles and elongated dislocation substructures. A proper annealing temperature for martensitic steels received 30% reduction, showing a good combination of a high strength, 1230MPa, and an adequate total elongation. 9.4%, was found as 500°C.