Rapid heat treatment yields excellent strength and ductility balance in a wear-resistant steel

Abstract

The rapid heating treatment with different tempering temperatures of 160, 200 and 320 °C was innovatively applied in one developed martensitic wear-resistant steel. The elaborate characterization on the evolution of microstructure-mechanical properties including the wear performance in different tempering temperatures were compared. Results manifested that the rapid heating treatment yielded a peak performance in the martensitic wear-resistant steel when tempered at 200 °C, by which the tensile strength and elongation were 1762.46 MPa and 13.13%, respectively, accompanied by the highest product of strength and elongation of 23.14 GPa·%. The enhanced work hardening contribution caused by the refined martensitic laths and carbides, as well as the appropriate recovery leaded to the peak performance at 200 °C. However, the mechanical properties both deteriorated by tempering at 160 and 320 °C subjecting to either the stress concentration or the coarsen carbides. Besides, the Baker–Nutting relationship between carbides and the matrix was established and furtherly proved the coarsen carbides resulted in the worst elongation by tempering at 320 °C. In addition, the main strength differences caused by different tempering temperatures were the grain refinement strengthening, dislocation strengthening, and precipitation strengthening, in which the grain refinement and precipitation strengthening played the dominating role. The current findings provide foundation for the industrial application of rapid heating techniques on the high-performance martensitic wear-resistant steels.