共查询到19条相似文献,搜索用时 109 毫秒
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介绍了由英国Davy开发的铝热连轧凸度闭环控制系统.内容涉及凸度控制的理论依据和关键环节.以及该系统各功能模块的作用。带材的凸度控制是铝热连轧机控制领域的关键技术之一。 相似文献
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中铝西南铝从国外引进的1+4热连轧生产线是我国第一条具有世界先进水平的铝热连轧线。该生产线的自动凸度控制系统AGC是由一级PLC和二级计算机组成的。一级PLC系统完AGC的执行与反馈控制,二级计算机完成凸度控制的模型计算和设定,整个控制系统达到了当今世界最高水平。本文将对该生产线的自动凸度控制系统作全面详细的介绍。 相似文献
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提出了用于热连轧分层递阶智能控制中的张力复合最优控制系统,板形板厚协调最优控制和速度设定的温度控制等3个子控制系统的优化设计方案,应用轧制主程和二次型目标函数推出板形板厚协调闭环最优控制、穿带过程辊缝最佳校正、轧辊凸度实时估计,最佳轧辊凸度设定和最佳弯辊力设定等热连轧过程优化策略。 相似文献
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三、带钢热轧机的板形检测和 控制系统 1.具有喷水式平直度检测器的控制系统 日本水岛厂带钢热连轧机的板形控制系统包括凸度控制和平直度控制,如图15所示。在轧制带钢时,沿宽度方向的厚度分布(带钢凸度)同平直度有密切关系。轧制过程产生的极其微小的凸度变化就足以改变平直度。相反地,平直度的变化却极少引起带钢凸度的变化。在实际轧制过程中,要求带 相似文献
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为了提高板形控制精度,对凸度平坦度控制耦合关系以及板形板厚控制耦合关系进行深入的研究分析,并采用相应的解耦控制策略是十分必要的。在板形板厚解耦设计的基础上,分析了不同控制方案下凸度平坦度控制之间的耦合影响关系,建立了相应的凸度平坦度耦合模型,并对其耦合特性进行了分析比较;之后,针对耦合模型特点进行凸度平坦度半解耦设计,以补偿凸度控制和平坦度控制之间的耦合影响关系,进而设计凸度平坦度解耦控制系统,并给出热连轧机组凸度平坦度解耦控制应用策略,组成完整的动态板形控制系统。在某厂1580 mm四辊七机架热连轧机组投入使用后,较好地补偿了板形板厚控制、凸度平坦度控制之间的耦合影响关系,板形控制精度明显提高。 相似文献
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从板形控制方程和生产线的板凸度控制结构入手,针对"1+4"热连轧生产线的板形板凸度控制系统的轧制力分布、工作辊冷却喷射、工作辊弯辊力控制、轧制力跟随控制等功能及其实现作了全面详细的介绍,给出了板形板凸度的实时控制方法,对工艺技术的提高和带材板形的改善有很好的帮助. 相似文献
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铝合金热连轧板形控制策略 总被引:1,自引:0,他引:1
本文对铝合金板带热连轧板形控制进行分析,介绍了板形的概念,板带材凸度的影响因素及控制机构,热轧板带凸度及板形控制数学模型,热连轧板形控制策略和板形控制实践。 相似文献
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板凸度和平直度是衡量板形质量的重要指标,它们既相互独立又彼此相互作用,而板凸度主要取决于有载辊缝的形状,所以准确计算辊系的弹性变形,对辊缝的设定有重要意义。采用影响函数方法对UCM轧机的辊系弹性变形进行了系统分析,通过修改工作辊、中间辊和支撑辊的影响函数模型,建立更适合现场的模型,用Vsual Basic语言编写计算流程的程序,设定初始数据,采用Bland—Ford轧制力计算公式进行计算。通过计算,第1机架轧制力的计算值与实测值相差8.2%,后面各机架与实测值更为接近,因此,所用方法是可行的。进一步分析得出影响有载辊缝形状的诸因素(辊间压力、辊间压扁、轧制力、挠度、弯辊力等)的结果,并与现场进行比较,达到提高板形质量的目的。 相似文献
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The internal radiative contributed on heat transfer will enhance the heat transport inside the crystalline phase during growth the transparent sapphire crystal using a heat-exchanger-method (HEM). The artificially enhanced thermal conductivity of the solid to include the internal radiation effect was used in the present study. Numerical simulations using FIDAP were performed to investigate the effects of the thermal conductivity on the shape of the melt-crystal interface, the temperature distribution, and the velocity distribution. Heat transfer (including radiation) from the furnace to the crucible and heat extraction from the heat exchanger can be modeled by the convection boundary conditions. In the present study, we focus on the influence of the conductivity on the shape of the melt-crystal interface. Therefore, the effect of the others growth parameters during the HEM crystal growth was neglected. For the homogenous conductivity (km=kS=k), the maximum convexity decreases as k increases and the rate of maximum convexity increases for a higher conductivity is less abrupt than for a lower conductivity. For the no homogenous conductivity (km≠kS), the higher solid's kS generates lower maximum convexity and the variation in maximum convexity was less abrupt for the different melt's km. The maximum convexity decreases slightly as the enhance conductivity of the sapphire crystal increases. The effects of the anisotropic conductivity of the sapphire crystal were also addressed. The maximum convexity of the melt-crystal interface decreases when the radial conductivity (ksr) of the crystal increases. The maximum convexity increases as the axial conductivity (ksz) of the crucible increases. 相似文献
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Jiri Plesek Heidi P. Feigenbaum Yannis F. Dafalias 《Canadian Metallurgical Quarterly》2010,136(4):477-484
The present paper examines the convexity of the yield surface in the directional distortional hardening models by Feigenbaum and Dafalias. In these models anisotropy develops through kinematic and directional distortional hardening, supplemented by the classical isotropic hardening, and the associative flow rule is used. However, the issue of convexity, which naturally arises due to the distortion of the yield surface, was not fully addressed. The present paper derives the necessary and sufficient conditions to ensure convexity of the yield surface for the simpler Feigenbaum and Dafalias models, but it is not as straightforward to derive corresponding conditions for convexity of the Feigenbaum and Dafalias model version which contains an evolving fourth-order tensor. In this case convexity will be addressed first in general and then at the limit state for which simple restrictions on the material constants to ensure convexity are derived. Numerical examples will show that some of the yield surfaces simulated in the original Feigenbaum and Dafalias publication will not stay convex if loaded beyond what was done in these publications. Therefore the material constants for these cases are recalibrated based on the derived relations for satisfaction of the convexity requirement, and the fitting of the yield surfaces is repeated with the new set of constants and compared with the previous case. 相似文献
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Twenty-three patients with Duchenne muscular dystrophy and scoliosis were studied. In all but one patient the major convexity was to the side of the dominant hand. The unsupported growing spine is easily unbalanced by asymmetrical forces imposed on it. From our observations we believe major use of a single upper extremity will result in scoliosis with the major convexity toward the side of the dominant hand. Management should include counterbalancing the postural abnormality imposed by hand dominance as well as unloading the spine frequently during the patient's waking hours. 相似文献
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在带钢轧制过程中,针对工作辊轴向方向凸度分布不均匀造成轧后带钢内部应力分布不合理,导致带钢局部出现黏结被撕断的问题,根据涡流加热原理,设计了电磁加热梁装置,动态地改变工作辊局部圆周凸度,降低轧后带钢内部的残余应力。该装置与板形控制系统有效结合,使板形测量值更加接近于设定值。经过现场测试和工业验证,该装置有效降低了带钢内部应力分布不合理状况,达到提高板形控制精度、改善带钢板形质量的目的,满足了轧机的精细板形控制要求。 相似文献
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