Modeling of Cracks Presence in Steel after Hot Rolling

The optimal material processing in steel industry is difficult because of the multi-constituent and multiphase character of the commercial steels, variety of the possible processing paths, and plant specific equipment characteristics. This paper shows implementation of the genetic programming approach for crack presence modeling after rolling. The data (110 samples covering 7 different steel grades) on diffusive annealing, last pass rolling temperature, chemical composition of steel (weight percent of Mn, Cr, Mo and V), steel bar dimensions (width and thickness), heating time of the first and the last batch billet were collected during daily production. The manual ultrasound method was used for crack detection. On the basis of the monitored data a mathematical model for crack presence was developed by genetic programming. For the modeling it was adopt that after the rolling the material was treated equally. The modeling results assume that the material processing after rolling is probably very influential on crack occurrence.