Impact of Surface Structure Control Cooling during Continuous Casting on Hot Ductility of Microallyed Steel

Abstract

Crack formation on the surface of continuously cast microalloyed steel can cause severe production problems. In the present investigation, the impact of the thermal history of "Surface Structure Control Cooling" (SSCC) on the ductility behavior of Ti-killed microalloyed steel is examined with the goal of preventing transverse cracks. The SSCC heat treatment consists of a double phase transformation as a result of intensive cooling and reheating. Metallography and transmission electron microscopy analysis are carried out to describe the evolution of microstructure and precipitation state. In addition, the precipitate phase fraction, mean radius, and number density are simulated with the thermokinetic software MatCalc and compared with experimental results. The results of the computer simulations are in good agreement with experimental observation and a clear correlation between precipitation and reduced ductility is observed.