Estimation of Internal Cracking Risk in the Continuous Casting of Round Bars

An internal cracking indicator is designed to quantify the risk of hot tearing in the continuous casting of round billets. For this purpose, the tensional state of the bar is acquired by implementing a thermo‐mechanical model that uses a steel material law calibrated with hot tension tests. The cracking indicator is then applied to the phenomenon of diametral pinch‐roll compression. Critical combinations of casting speed and steel carbon content are defined to estimate the cracking risk. At last, macro‐etching is applied on industrial bars in order to reveal internal cracking, which is then compared to model results to assess its predictability. Influence of pinch‐roll pressure and roll shape on the cracking risk is also analyzed. A modeling methodology is developed to assess the risk of hot‐tearing in round billets, consisting of a thermo‐mechanical model followed by the codification of failure criteria. A cracking indicator is then obtained and applied to evaluate the effect of pinch‐roll compression. Finally, influence of operative variables on the cracking risk is analyzed. Model results present a good agreement with cracked bar macro‐etchings.