Increase in the structural strength of carbon steel by HTMT with isothermal decomposition of austenite

Abstract

1. After HTMT with isothermal decomposition of austenite in the pearlitic region (HTMDIT) the mechanical properties of carbon steel U8 are higher at all decomposition temperatures of austenite tested than after standard isothermal treatment (DIT). 2. After HTMDIT the maximum increase in the strength (σb increases by 8 kgf/mm2, σ0.2 by 15 kgf/mm2) and ductility (Sk by 57 kgf/mm2, ψ by 15%) in comparison with DIT is obtained with isothermal decomposition of austenite at 500°. 3. The increase in the structural strength after HTMDIT as compared with DIT is also confirmed by the resistance to microplastic deformation and the fracture toughness of samples with a started crack.