1. ArcelorMittal Research June 2008 Optimization of lubrication and cooling in cold rolling from 17 mars to 12 September 2008 - RFCS Optcoolub - Tutor: NGO Quang Tien Project leader : Nicolas LEGRAND
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7. Thermal simulator : HTC(x) What happen in a high strip temperature “Typically Ts >100°C at least “ ? Problem the material-coolant interface: vapor ,HTC The first appearance of bubbles promotes the exchange of heat. Higher the temperature higher the agitation of water “convection" 20°C 300°C
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10. Thermal simulator: Rheology Problem : the graphics show that strip rheology depends on the strain rate We made those experiences for 3 steel grades of AVILES. To validate the LUCY-BALISTIK model. Influence of speed Our experiment Influence of temperature Literature data
11. Thermal simulator: Rheology Advantage predicting precisely the evolution of metal hardness along the rolling mill Improvement Integrate LUCY-BALISYIK model in our simulator:
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13. Conditions defined for realization at stand #4 of Aviles TDM2 Brno has characterized 13 roll cooling configurations for Optcoolub project
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15. AV13-4 Evolution of Flux and HTC with a temperature of the cylinder HTC mesuré et HTC Loi en fonction de la température moyenne de surface de cylindre 0 5000 10000 15000 20000 25000 0 50 100 150 200 250 300 Température moyenne de surface cyl °C HTC ( w / m ² K ) HTCmoy w / m ² K Flux dependency to roll surface temperature is higher
16. Results with our analysis Results with Brno analysis ±500 : 13- 12- 8- 6 - 11 HTC average for each configuration “ position 4” at T water = 0°c Results obtained with Brno analysis Results with Brno analysis ±200 : 13- 6- 8- 12 - 9 Configuration common among all tests: 13-6-12 HTC average for each configuration
17. If we use the flux as an indicator of the efficiency of cooling, somme differences in the classification are obtained (compared to classification with HTC) However, we can conclud that config. N°6 is a good configuration as already concluded by Brno Average flux for each configuration 0 200 400 600 800 1000 1200 1400 1600 1800 Flux moy (w/m²) AV4-1 AV4-2 AV4-3 AV4-4 AV4-5 AV4-6 AV4-7 AV4-8 AV4-9 AV4-10 AV4-11 AV4-12 AV4-13 Mean heat Flux for each test. Sensor n°4 Phi moyenne
18. N°13 Uniformity of HTC with distribution of flow Conclusions : globally, when the flow is strongly heterogeneous, the HTC seems heterogeneous also, but HTC does not follow irregularities of the flow HTC w/m²°C
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