共查询到20条相似文献,搜索用时 171 毫秒
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钢板层流冷却终冷温度控制精度决定了钢板的性能和质量,而温降数学模型又是层流冷却控制的核心。随着钢板厚度的增加,钢板内部导热成为主要的传热方式,因此,建立二维导热温降模型,并利用有限元法求解。其中,水冷换热系数的精度决定了导热数学模型计算的准确率,利用BP神经网络的非线性、高容错性等优点建立了水冷换热系数模型。利用MATLAB仿真实现,预测结果显示产品合格率95%以上。因此,模型具有使用价值。 相似文献
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给出了钢板厚度方向温度分布随时间变化的数学模型,据此可以计算出钢板在不同冷却条件下的冷却时间和平均冷却速度,进而提出了钢板加速冷却过程的控制策略。 相似文献
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带钢在层流冷却过程中距表面较近的区域温度存在反复升降的现象,造成厚度方向上组织和性能的差异。结合酒钢CSP热轧带钢生产数据,建立一维热轧带钢有限元模型,计算层流冷却过程中带钢的温度场。提出了冷却过程中带钢冲击穿透深度的概念,并初步探究其影响因素。厚度为3和4mm的带钢计算得出的卷取温度比实测温度分别高3和8℃,相对误差分别为0.44%和1.16%,验证了模型和假设的合理性。结果表明,冷却过程中冲击穿透深度受带钢的导热系数、平流区的对流换热系数、带钢表面温度和喷嘴分布的影响;带钢上表面喷嘴分布较少,冲击穿透深度随对流换热系数的增大而增加,下表面喷嘴分布密集起主导作用,增加对流换热系数,冲击穿透深度几乎不受影响。 相似文献
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建立了热轧带钢层流冷却过程中温度场的三维有限元模型,对3 mm厚带钢轧后冷却过程带钢温度场进行模拟计算,得出卷取温度比现场测量值低9.5 ℃,相对误差为1.42%,验证了模型和假设的合理性。研究了上喷嘴直径对带钢温度的影响,带钢上表面宽度方向上存在2种不同的冷却区域:位于喷嘴正下方层流冷却过程中交替经过冲击区和平流区的区域和位于两喷嘴之间层流冷却过程中只经过平流区的区域,这造成带钢宽度方向上温度分布不均匀。计算结果表明,喷水量保持不变的情况下,存在一个最佳喷嘴直径,使带钢宽度方向上温度分布更均匀。喷水速度保持不变,增加喷嘴的直径有利于带钢宽度上方温度均匀,但增加了喷水量,降低了带钢的卷取温度。 相似文献
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Tathagata Bhattacharya Debadi Chakraborty Vikas Singh 《Metallurgical and Materials Transactions B》2006,37(6):1015-1024
The coil cooling and storage unit (CCSU) is used to cool cold-rolled coils to the temper rolling temperature after the annealing
cycle is over at the batch annealing furnace (BAF) in a cold rolling mill (CRM). In the CCSU, the coils are kept on the cooling
bases for any fixed time irrespective of the grade and tonnage. Therefore, the need for a mathematical model to accurately
predict the cooling time of the coils was felt. The current study involves experimental and numerical analysis of a stack
of coils with respect to heat transfer and fluid flow. A comparative study was carried out to ascertain the relative merits
of convectors and “C” inserts (CIs) in the cooling the coils. The air flow distribution for the case of different convectors
and CIs was measured by means of a full scale physical model. Two different mathematical models were applied to model the
fluid flow and flow distribution through the stack of coils. The first flow model uses the hydraulic resistance concept for
estimating the air flow rate distribution, whereas the second flow model uses commercial computational fluid dynamics (CFD)
software and predicts the velocity distribution in the flow path between two coils in a stack. The predictions from these
two models compare well with the experimental data. The flow models were used to calculate the average heat-transfer coefficient
in different flow passages in a stack. The heat-transfer coefficients thus obtained were used to tune and validate a two-dimensional
transient heat-transfer model of coils. The heat-transfer model predicts the cooling time of coils accurately and also suggests
a possible reduction of cooling time if CIs are used in place of convectors. 相似文献
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轧辊热凸度是影响热带钢连轧机负载辊缝的重要因素,高效率的工作辊冷却水系统是生产高质量热轧板带的重要保证。为了设计工作辊的冷却水量及分布,建立了工作辊横断面温度场计算模型、轴对称平面温度场计算模型和热凸度计算模型。在此基础上,采用优化设计方法对1450热带钢连轧机工作辊冷却水量及其沿轧辊周向和轴向的分布进行优化设计。 相似文献
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中厚板水幕冷却温度预报和冷却参数设定模型的研究 总被引:2,自引:0,他引:2
利用数值计算方法建立了多水幕下中厚板温度场计算模型,结合某中板厂的水冷工艺用模拟计算方法,分规格、分控制阶段回归出19个温度以 模型和其自学习模型;建立了水幂冷却工艺参数设定值计算模型。 相似文献
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A metallurgical through‐process model is presented which describes the microstructural evolution and predicts the final mechanical properties of low carbon steel during hot strip rolling. Process models concern the thermal and deformation phenomena, which take into account the strain, strain rate and temperature distribution along the length of the strip. And the metallurgical models cover five modules, which are (i) austenitization of cast slab in reheating furnace, (ii) recrystallization of austenite in hot rolling, (iii) phase transformation of austenite‐ferrite in laminar cooling on the run‐out‐table, (iv) grain growth after coiling, and (v) final structure‐mechanical properties of products. Temperature is the main parameter and has dominant influence on the microstrutural evolution and the mechanical properties. The related temperature variation in hot strip rolling concerns air cooling, scaling, water cooling, heat transmission by roll contact, heat generation by deformation and friction. These complex factors are incorporated into the thermal models to simulate the temperature distribution along the length of the strip from the reheating furnace exit to the down‐coiler. A self‐learning algorithm is employed to improve the calculation accuracy and the computational temperatures are compared with the measured ones at typical locations. In the structure‐property relationships, two key process parameters (e.g., finishing exit temperature (FT7) and coiling temperature (CT)) are introduced in the model to consider the influence of morphology of microstructure on mechanical properties. 相似文献
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In this paper, a compensation control model of secondary cooling process of billet continuous casting for quality steel has been presented. The effects on the spray control of the various parameters such as steel superheat, casting speed, cooling water temperature and chemical component of steel were considered. The parameters of control model were determined to associate with the two‐dimensional heat transfer equation and solved by finite‐difference method. Effects of steel superheat and cooling water temperature on surface temperature, solidification structure and solidifying end point were discussed. Results indicate that steel superheat significantly affects solidification structure and solidifying end point but has a little effect on slab surface temperature. Moreover, secondary cooling water temperature affects surface temperature and solidifying end point but has a little effect on solidification structure. The surface temperature and solidifying end point can be maintain stabilized through applying the compensation control model when steel superheat and cooling water temperature vary. The models have been validated by industrial measurements. The results show that the simulations are in very good agreement with the real casting situation. 相似文献
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钢液连铸二次冷却的效果直接影响连铸坯质量,为了合理地控制二次冷却过程,多种静态和动态控制工艺模型被提出。系统综述了目前二冷静态和动态控制工艺模型的发展,包括二冷区各回路水量与拉速呈一次线性或二次曲线关系的二冷控制工艺模型、基于修正有效拉速的二冷动态控制工艺模型和基于在线传热计算的二冷动态控制工艺模型等,以及基于钢液过热度和二冷进水温度的二冷控制先进工艺模型和基于在线温度测量反馈调节各回路水量的二冷动态控制工艺模型。随着二冷控制工艺模型的发展,其控制的实时性、可靠性、准确性以及运行的稳定性也逐渐提高,从而为高质量铸坯生产及智能化二冷控制奠定了基础。 相似文献
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H. Fang M. G. Mecozzi E. Brück S. van der Zwaag N. H. van Dijk 《Metallurgical and Materials Transactions A》2018,49(1):41-53
A 3D model has been developed to predict the average ferrite grain size and grain size distribution for an austenite-to-ferrite phase transformation during continuous cooling of an Fe-C-Mn steel. Using a Voronoi construction to represent the austenite grains, the ferrite is assumed to nucleate at the grain corners and to grow as spheres. Classical nucleation theory is used to estimate the density of ferrite nuclei. By assuming a negligible partition of manganese, the moving ferrite–austenite interface is treated with a mixed-mode model in which the soft impingement of the carbon diffusion fields is considered. The ferrite volume fraction, the average ferrite grain size, and the ferrite grain size distribution are derived as a function of temperature. The results of the present model are compared with those of a published phase-field model simulating the ferritic microstructure evolution during linear cooling of an Fe-0.10C-0.49Mn (wt pct) steel. It turns out that the present model can adequately reproduce the phase-field modeling results as well as the experimental dilatometry data. The model presented here provides a versatile tool to analyze the evolution of the ferrite grain size distribution at low computational costs. 相似文献