【作者】 吴建峰；

【导师】 王国栋；

【作者基本信息】 东北大学 ， 材料加工工程， 2009， 博士

【摘要】 为了提高热轧带钢粗轧机组宽度控制精度和提高成材率,广泛开展了粗轧机组金属变形规律的研究。本文以宝钢2050粗轧机组的现场条件为背景,对HV(H：平轧,V：立轧)调宽轧制过程进行了有限元仿真分析和优化研究。所取得的新进展如下：1)用大型刚塑性有限元软件建立立轧/平轧的三维热应力耦合轧制模型,并将其应用到宝钢2050粗轧机组仿真研究中。选取宝钢轧制带钢的现场实际参数进行模拟计算,得出的粗轧出口宽度值与实测值吻合良好,充分验证了模型的有效性。为了解决宝钢2050粗轧机组宽度难以控制的问题,对现场各种轧制工艺的宽展进行了仿真计算,并给出了自然宽展、纯狗骨宽展和综合宽展的分布规律。2)用刚塑性三维热应力耦合有限元模型,对宝钢2050热轧带钢粗轧机组轧制过程进行了全过程模拟。模拟所得的带钢尾部形状与现场图片吻合良好,有效地验证了计算模型。通过有限元仿真计算,研究带钢尾部鱼尾形状形成机理,得到了粗轧各道次轧后带钢尾部鱼尾切损的分布规律。提出了立轧/平轧负张力控制轧制带钢尾部的方法,通过计算表明该方法能够有效减少带钢尾部鱼尾切损量。3)建立立轧/水平轧制过程缩微有限元模型,分析了不同板宽、宽度压下量时带钢头尾部的失宽规律,并以此取反作为立辊短行程控制曲线进行加载计算模拟。通过轧制后的头尾形状反复修正短行程曲线,最后得出了较好的短行程控制曲线。随后建立了短行程的多项式过程控制模型,实际生产证明可以在一定程度上进一步减少切损。4)采用粒子群算法对粗轧宽展模型中的狗骨宽展系数进行优化,解决了传统方法难以解决的问题,结果表明优化后的模型控制效果明显优于原来模型,体现了粒子群算法在优化领域的优越性。5)通过分析影响精轧自然宽展的主要因素,运用递推最小二乘法建立了精轧自然宽展的综合预报模型,仿真结果和实际生产数据分析均表明其预报精度优于老模型。上述研究工作揭示了HV轧制过程的变形规律,提出了减少带钢头尾切损的若干工艺方法,得到了较好的短行程控制多项式曲线,也表明了粒子群算法在优化领域的良好效果,建立了精轧自然宽展综合预报新模型。经过宝钢2050热轧现场应用的检验,证明了本文研究方法和结果是富有成效的。更多还原

【Abstract】 In order to improve the width control and crop loss in hot strip roughing mill, HV rolling process(H: horizontal, V:vertical) are studied and optimized for roughing mill of 2050mm tandem hot strip line in Bao Steel. The main achievements contain:1) A 3D thermo-mechanical coupled model for vertical/horizontal rolling is established using a rigid-plastic FEM software, which is applied to simulate the rolling processes on 2050mm roughing mill of Bao steel. The calculated width of strip using the actual parameters is in good agreement with the measured value at the exit of roughing mill, thus the model is effective. Aiming at the question that the strip width is controlled difficultly, in this study, the spread law is investigated by FEM simulation. The law of the strip spread (natural spread, dogbone spread and combined spread) is obtained.2) Using the 3D thermal-mechanical coupled rigid-plastic FEM model, we simulated the rolling processes on 2050mm hot roughing mill of Baosteel company. The calculated tail shapes of st rip are in good agreement with actual pictures, thus the model is validated. Based on FEM simulation, the forming mechanism of fish-tail on the strip tail end was investigated, and the distribution of tail cropping at each pass was obtained. A negative tension control between vertical and horizontal rollers was brought forward, which could reduce the crop loss offish-tail according to calculated results.3) The 3D thermal-mechanical coupled FEM model for edging and horizontal rolling also has been used to investigate the SSC model for controlling head and tail shape in the roughing mill of 2050mm hot mill of Baosteel. The law of width shrinkage on head and tail ends is analyzed, and a new SSC model is induced by the function of both the steel width and the draught of edging. By comparison of calculation results of the original model and the new model, it can be seen that the width shrinkage of the head and tail ends is well decreased using the SSC model established.4) Particle Swarm Optimization(PSO) algorithm is applied in model optimization more and more frequently and it was used to optimize the mathematical model for the width expansion. The result from the computer simulation demonstrated the algorithm’s validity and effectiveness.5) Under the analysis of the main factor influencing on the width spreading at finishing mill(FM),a integrated width spreading and narrowing prediction model has been established based on the the recursive least square method(RLSM), The result from the computer simulation and actual production demonstrated that the accuracy of width spreading prediction was improved.In a sentence, the series of research works have brought to light the laws of HV rolling process, some technics methods have been brought forward, which could reduce the crop loss of the strip head and tail ends, and developed the relevant programs,and a better SSC polynomial curve is obtained,also the algorithm’s validity and effectiveness is proved,finally,a integrated width spreading and narrowing prediction model is established.It has been proved that these obtained results are reasonable by applications in Baosteel.更多还原