共查询到19条相似文献,搜索用时 250 毫秒
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矩形坯连铸凝固传热的数学模型 总被引:5,自引:0,他引:5
根据连铸矩形坯凝固传热特点,在上海浦东钢铁有限公司1号连铸机二冷系统改造中,动用直接差分法建立了二维非稳态矩形坯凝固传热数学模型,已应用于连铸凝固过程的模拟计算,在分析拉速、浇注温度等在数对钢水凝固过程的影响后,为提高拉速找到了理论依据。 相似文献
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根据连铸矩形坯凝固传热特点,运用直接差分法建立了二维非稳态矩形坯凝固传热模型,对首钢矩形坯进行了凝固末端位置的模拟计算,得出了3种断面的液芯长度,找了搅拌器的合适位.置。 相似文献
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介绍了连铸坯在二冷区凝固传热的传热方式,传热系数和影响二冷区传热的因素,同时也介绍了二冷区传导热流的计算公式以及用来表达传热系数与水流密度之间的经验公式。 相似文献
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根据连铸矩形坯凝固传热特点,在上钢三厂转炉1号连铸机二冷系统改造中,运用直接差分法计算了二维非稳态矩形坯凝固传热数学模型,又依二冷区各段出口目标温度不随拉速改变为配水原则,进行了矩形坯连铸机二冷配水计算,为该铸机提高拉速找到了理论依据。 相似文献
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根据连铸坯凝固传热的特点,在电炉厂小方坯的连铸机二冷改造过程中,建立了二维的传热模型。对改造前后的系统进行分析,为二冷系统的改造提供了理论依据,进而实现二冷三段和四段汽雾改造。 相似文献
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凝固模型在高碳钢方坯连铸中的应用 总被引:5,自引:0,他引:5
依据湘钢现场条件,建立了连铸方坯凝固传热数学模型,分析了过热度、拉坯速度、二次水量对高碳钢方坯凝固过程的影响,确立了二次冷却与高碳钢二次枝晶间距的关系式,提出了改善高碳钢方坯连铸中心缩孔的途径。 相似文献
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C. A. Muojekwu I. V. Samarasekera J. K. Brimacombe 《Metallurgical and Materials Transactions B》1995,26(2):361-382
Transient heat transfer in the early stages of solidification of an alloy on a water-cooled chill and the consequent evolution
of microstructure, quantified in terms of secondary dendrite arm spacing (SDAS), have been studied. Based on dip tests of
the chill, instrumented with thermocouples, into Al-Si alloys, the influence of process variables such as mold surface roughness,
mold material, metal superheat, alloy composition, and lubricant on heat transfer and cast structure has been determined.
The heat flux between the solidifying metal and substrate, computed from measurements of transient temperature in the chill
by the inverse heat-transfer technique, ranged from low values of 0.3 to 0.4 MW/m2 to peak values of 0.95 to 2.0 MW/m2. A onedimensional, implicit, finite-difference model was applied to compute heat-transfer coefficients, which ranged from
0.45 to 4.0 kW/m2 °C, and local cooling rates of 10 °C/s to 100 °C/s near the chill surface, as well as growth of the solidifying shell. Near
the chill surface, the SDAS varied from 12 to 22 (μm while at 20 mm from the chill, values of up to 80/smm were measured. Although the SDAS depended on the cooling rate and local solidification time, it was also found to be a direct
function of the heat-transfer coefficient at distances very near to the casting/chill interface. A three-stage empirical heat-flux
model based on the thermophysical properties of the mold and casting has been proposed for the simulation of the mold/casting
boundary condition during solidification. The applicability of the various models proposed in the literature relating the
SDAS to heat-transfer parameters has been evaluated and the extension of these models to continuous casting processes pursued. 相似文献
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Real-time simulation of heat transfer in continuous casting 总被引:10,自引:0,他引:10
Seppo Louhenkilpi Erkki Laitinen Risto Nieminen 《Metallurgical and Materials Transactions B》1993,24(4):685-693
A real-time heat-transfer model for continuous slab casting is presented. The model calculates the strand temperatures and
the solid shell thickness profile along the machine as a function of the actual casting variables, strand geometry, and steel
grade. The special requirements con-cerning the real-time use of the model and, in general, the accuracy of the model are
also studied and discussed. The model has been tested by carrying out industrial trials. Some examples of the differences
between the calculated and measured surface temperatures are presented. A spe-cial procedure to determine the boundary conditions
for the secondary cooling zones from tem-perature measurements is also described. 相似文献
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Etienne J. F. R. Caron Amir R. Baserinia Harry Ng Mary A. Wells David C. Weckman 《Metallurgical and Materials Transactions B》2012,43(5):1202-1213
Thermal modeling of the direct-chill casting process requires accurate knowledge of (1) the different boundary conditions in the primary mold and secondary direct water-spray cooling regimes and (2) their variability with respect to process parameters. In this study, heat transfer in the primary cooling zone was investigated by using temperature measurements made with subsurface thermocouples in the mold as input to an inverse heat conduction algorithm. Laboratory-scale experiments were performed to investigate the primary cooling of AA3003 and AA4045 aluminum alloy ingots cast at speeds ranging between 1.58 and 2.10 mm/s. The average heat flux values were calculated for the steady-state phase of the casting process, and an effective heat-transfer coefficient for the global primary cooling process was derived that included convection at the mold surfaces and conduction through the mold wall. Effective heat-transfer coefficients were evaluated at different points along the mold height and compared with values from a previously derived computational fluid dynamics model of the direct-chill casting process that were based on predictions of the air gap thickness between the mold and ingot. The current experimental results closely matched the values previously predicted by the air gap models. The effective heat-transfer coefficient for primary cooling was also found to increase slightly with the casting speed and was higher near the mold top (up to 824 W/m2·K) where the molten aluminum first comes in contact with the mold than near the bottom (as low as 242 W/m2·K) where an air gap forms between the ingot and mold because of thermal contraction of the ingot. These results are consistent with previous studies. 相似文献
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应用二维非稳态传热数学模型,以目标表面温度控制为指导,建立板坯连铸机二冷配水计算模型,比较了二冷区三种实时控制模式,指出浇注温度前馈的表面温度反馈控制更有利于稳定铸坯表面温度分布和改善铸坯质量。 相似文献