PREDICTION OF SURFACE DEFECTS IN STRUCTURAL STEELS USING A REAL TIME COUPLED THERMAL-MECHANICAL MODEL

article in a collection out of WoS and Scopus

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The production of structural steel grades with various mechanical properties is still increasing nevertheless problems related to the quality of the strands persist. To obtain a strand of the highest possible quality or, in the best case, with no defects, the macro-solidification model monitoring the temperature field is needed. The authors of this article already developed the temperature solidification model called BrDSM and the effort depicted in this work is concentrated to the creation of the so-called thermo-mechanical model where the stress as well as temperature distribution in the strand is the crucial factor of the strand quality in order to avoid the zero ductility temperature (ZDT) and the liquid impenetrable temperature (LIT) in locations with bending and unbending of the strand. The article describes the limits of the use of these models and the theoretical description of implementation in a real casting process. The combination of these models in terms of influence of temperature and stress distributions is explained. The thermo-mechanical model also deals with the shrinkage of the strand in the whole scale of descending temperature, with mechanical deformations due to cooling rollers and it contains the precisely determined cooling intensities of cooling nozzles from laboratory experiments. The outputs from the thermo-mechanical model will be used in the future to resolve complex relationships, which allow the prediction of defects formations.

The production of structural steel grades with various mechanical properties is still increasing nevertheless problems related to the quality of the strands persist. To obtain a strand of the highest possible quality or, in the best case, with no defects, the macro-solidification model monitoring the temperature field is needed. The authors of this article already developed the temperature solidification model called BrDSM and the effort depicted in this work is concentrated to the creation of the so-called thermo-mechanical model where the stress as well as temperature distribution in the strand is the crucial factor of the strand quality in order to avoid the zero ductility temperature (ZDT) and the liquid impenetrable temperature (LIT) in locations with bending and unbending of the strand. The article describes the limits of the use of these models and the theoretical description of implementation in a real casting process. The combination of these models in terms of influence of temperature and stress distributions is explained. The thermo-mechanical model also deals with the shrinkage of the strand in the whole scale of descending temperature, with mechanical deformations due to cooling rollers and it contains the precisely determined cooling intensities of cooling nozzles from laboratory experiments. The outputs from the thermo-mechanical model will be used in the future to resolve complex relationships, which allow the prediction of defects formations.

CONTINUOUS CASTING; CRACK FORMATION CRITERIA; THERMAL MODEL; MECHANICAL MODEL; QUALITY PREDICTION

20.10.2021

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