Srovnání teplotního pole kontinuálně litých ocelových bram rozdílného chemického složení

Comparison of the Temperature Field Continuously Cast Steel Slabs of Different Chemical Composition

článek ve sborníku ve WoS nebo Scopus

en

Original numerical model was applied to the simulation of the transient temperature field of concast steel slab of two different chemical composition. The model solves the Fourieor-Kirchhoffs equation of the temperature field of slab- crystallizer system respectively slab-ambient system with these main thermophysical parameters : thermal conductivity, specific heat capacity, density and enthalpy. When both melts follow closely after each other, the critical state of so called break out occurs at a certain point secondary cooling zone of a caster. It is probably a combination of surface defects. However different chemical composition of two steels and their mixing is apparently decisive. Therefore the temperature model has simulated the temperature history of every point of a cross-section of a slab during its movement through the whole caster from the level of the melt in the crystallizer to the cutting torch for both melts and and for their mixture. Calculation of the temperature field of a slab has focused mainly on the part of the slab before the break out and its surroundings. Calculation results were compared graphically by means of a graph of temperatures in characteristic points of the cross section, a graph of isotherms in the critical cross-section passing through the break out including isoliquidus and isosolidus, a graph of isotherms in longitudinal sections and a graph of increase in thickness of a solidified shell. The results of the temperature field can establish a model of the chemical heterogeneity of steel supported by material expertise on samples taken from the break out

Pro řešení nestacionárního teplotního pole dvou kontinuálně odlévaných ocelových bram rozdílného chemického složení je použito originálního numerického modelu. Když obě tavby následují těsně po sobě, kritické místo t.zv. průvalu se nachází v určitém místě sekundární zony chlazení. Jedná se pravděpodobně o kombinaci povrchových defektů, avšak vliv rozdílného chemického složení je zřejmě rozhodující. Výsledky řešení teplotního pole pro obě tavby a jejich směs jsou vyjádřeny graficky. Jsou rovněž základem pro model chemické heterogenity ve spojení s materiálovou expertizou odebraných vzorků.

Original numerical model was applied to the simulation of the transient temperature field of concast steel slab of two different chemical composition. The model solves the Fourieor-Kirchhoffs equation of the temperature field of slab- crystallizer system respectively slab-ambient system with these main thermophysical parameters : thermal conductivity, specific heat capacity, density and enthalpy. When both melts follow closely after each other, the critical state of so called break out occurs at a certain point secondary cooling zone of a caster. It is probably a combination of surface defects. However different chemical composition of two steels and their mixing is apparently decisive. Therefore the temperature model has simulated the temperature history of every point of a cross-section of a slab during its movement through the whole caster from the level of the melt in the crystallizer to the cutting torch for both melts and and for their mixture. Calculation of the temperature field of a slab has focused mainly on the part of the slab before the break out and its surroundings. Calculation results were compared graphically by means of a graph of temperatures in characteristic points of the cross section, a graph of isotherms in the critical cross-section passing through the break out including isoliquidus and isosolidus, a graph of isotherms in longitudinal sections and a graph of increase in thickness of a solidified shell. The results of the temperature field can establish a model of the chemical heterogeneity of steel supported by material expertise on samples taken from the break out

kontinuálně litá brama, teplotní pole, chemické složení, heterogenita, numerický model, průval

concast slab, temperature field, chemical composition, heterogeneity, numerical model, breakout

2012

23.05.2012

Tanger

Ostrava

978-80-87294-31-4

METAL 2012 Conference proceedings (CD-ROM)

142–147

6