Dynamická simulace brámi během plynulého odlévání oceli pro velké rychlosti lití na výslednou kvalitu vnitřní struktury

Dynamic Simulation of Slab Centerline Behavior of the Continuous Casting Process during Large Speed Transitions and Their Effects on Slab Internal Quality

conference paper

en

The centerline quality of a continuously cast slab is one of the major quality indicators for further downstream processing to manufacture defect-free final products. Monitoring of centerline quality during casting can be approached either by direct measurement of the solidification front position or by online dynamic simulation based on a verified solidification model. ArcelorMittal Global R&D East Chicago Laboratory developed a dynamic solidification model to control secondary cooling for optimal slab surface temperature. One of the features of this model is the calculation and graphical display of liquid core position within the caster each 5 seconds. The model calculates the thermal distribution for 250 slices within the caster every 5 seconds. Each slice has its own thermal history and therefore during heavy speed transition cases (tundish fly, SEN change, ladle change or breakout prevention), the model takes into account the longer residence time of the slab inside the machine. These transition events can cause bridging inside the slab and centerline unsoundness will appear. This paper will present results of the model simulations during large casting speed changes on solidification behavior and quality. Furthermore possible countermeasures to prevent these undesired effects during speed changes will be discussed.

Kvalita ve středním řezu plynule odlévané brámi je jeden z hlavních ukazatelů kvality pro následné zpracování a docílení výrobku bez vad. Monitorivání středního řezu (línie tuhnutí) je prováděno pomocí on-line dynamickým modelem, jehož základ tvoří verifikovaný model tuhnutí. ArcelorMittal Global R & D East Chicago výzkumná laboratoř vyvinula dynamický model tuhnutí, který slouží k optimalizaci povrchové teploty brámy během sekundárního chlazení. Tento článek prezentuje výsledky simulací pro velkou rychlost lití a její vliv na změny procesu tuhnutí a výslednou strukturu. Budou navrhnuta též možná protiopatření, aby se zabránilo tomuto nežádoucímu efektu.

The centerline quality of a continuously cast slab is one of the major quality indicators for further downstream processing to manufacture defect-free final products. Monitoring of centerline quality during casting can be approached either by direct measurement of the solidification front position or by online dynamic simulation based on a verified solidification model. ArcelorMittal Global R&D East Chicago Laboratory developed a dynamic solidification model to control secondary cooling for optimal slab surface temperature. One of the features of this model is the calculation and graphical display of liquid core position within the caster each 5 seconds. The model calculates the thermal distribution for 250 slices within the caster every 5 seconds. Each slice has its own thermal history and therefore during heavy speed transition cases (tundish fly, SEN change, ladle change or breakout prevention), the model takes into account the longer residence time of the slab inside the machine. These transition events can cause bridging inside the slab and centerline unsoundness will appear. This paper will present results of the model simulations during large casting speed changes on solidification behavior and quality. Furthermore possible countermeasures to prevent these undesired effects during speed changes will be discussed.

Dynamická simulace, plinulé odlévání, bráma, sekundární chalzení

Dynamic Simulation, Continuous Casting, Slab, Secondary Cooling

2013

12.09.2013

VŠB - Technical university of Ostrava

Ostrava

978-80-260-3912-9

Steelsim 2013

1–12

12