Microstructural evolution in microalloyed steels during thermomechanical rod rolling

Abstract

Steel rods are hot-rolled at high strains and strain rates with a subsequent controlled cooling process to influence the microstructure. The microstructure and mechanical properties of the hot-rolled rods are controlled to produce high-strength fasteners in the cold heading process without subsequent heat treatment. In the present study, simulations of rod rolling by torsional deformation and controlled time-temperature schedules were conducted to examine the effects of thermomechanical processing parameters and microalloying additions on the microstructure evolution and mechanical properties of low-carbon steel rods. Transformation and precipitation behaviors during the thermomechanical process were investigated and related to the increased strength in the steel rods.