| Mould is the heart of continuous caster, and plays an important part in this area. During the processing of wide and thick slab continuous casting, mould heat transfer and mechanical behaviors have significant effects on the slab's quality. Due to the limited methods of detection, it is very difficult to obtain heat flux,distortion and the process of steel solidification in the mould, so numerical simulation becomes the important method to calculate mould heat transfer and mechanical behavior.Taking the mould of wide and thick slab continuous casting as an object, the analysis is focused on mould heat transfer and mechanical behaviors. A two-dimensional heat transfer inverse problem model is developed from the measured data of mould temperature by thermocouples embedded in various transverse and longitudinal sections. By identifying the heat flux between the mould and strand, the non-uniform mould heat transfer and strand solidification are calculated, which can reflect the real process. Based on it, the calculated temperature fields of mould, which are taken as thermal loads, are put into a two-dimensional mechanical model. The mechanical behaviors of copper plate are simulated. Casting speed, layer, copper thickness and ferrostatic pressure are taken into account.Calculated results of temperature field indicate:the simulated values of temperature from inverse mathematical model agreed well with the measured ones. The correctness and reliability of model was verified. The temperature and heat flux distribution shows obvious non-uniform characteristics. Along the casting direction, three layers of thermal couples decrease gradually. But distribution and variation shows the same as it, and non-uniformity decrease gradually. Heat transfer indicates inheritance trend in a great degree. The different casting speed has a different affection on temperature and heat flux on different locations of mould, and the hot face temperature has a sensitive reaction on it, and the other conditions were not changed, the average increment of casting speed was 0.15m/min, Mould hot face temperature increases 10℃more or less. The heat flux between mould/strand determines the distribution of shell thickness.Owing to the non-uniform heat transfer, the calculation results in respect of the thermal-mechanical behavior are non-uniform in each transverse section of mould. Through analyzing mechanical behavior of mould, maximum distortion of copper plate focuses on the central region. From the central line to the corner of copper plate, the deformation decreases gradually. When the distance below meniscus is 105mm, the distortion becomes the largest. The copper plate deformation acts as real-time transform according to measured temperature fluctuation, the distribution of distortion along wide direction is the same as the temperature distribution, Because of the non-uniformity of heat transfer, the distortion shows non-uniform, when the distance below meniscus is 325mm, the average increment of measured temperature is 1℃, the distortion of copper plate increase 0.02mm. The copper plate distortion increase as the casting speed increased. When the casting speed verify from 0.75m/min to 1.05m/min, the distortion increase from 0.60mm to 0.68mm.Compared with outside radius, the distortion of inside radius copper plate act more obviously. When the casting is 1.05m/min, the maximum distortion of inside radius copper plate is 0.87mm, and the maximum distortion of outside radius is 0.68mm,0.19mm more than outside radius. Building full size model, because of the differences of heat flux and cooling water flow in two wide faces, the distortion of inside radius and outside radius is different. Discussing other factors of mould distortion, when copper plate thickness of mould increase, mould heat resistance increase and copper plate temperature grow, the distortion increases. Ferrostatic pressure has a little influence on mould distortion, and the model is verified. |
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