【作者】 王晓南；

【导师】 邸洪双；

【作者基本信息】 东北大学 ， 材料加工工程， 2008， 硕士

【摘要】 为了提高热轧带钢粗轧机组宽度控制精度及提高成材率,改善产品的表面质量,开展了对粗轧机组金属变形规律的研究,并侧重对“狗骨”材在随后平轧过程中的变形情况进行了分析和比较,为制定合理的工艺规程提供可靠的依据。本文以梅山钢铁厂热轧机组的现场条件为背景,针对其粗轧中间坯距板边缘10mm-20mm的区域出现“黑线”的问题进行理论分析。本文运用有限元软件ANSYS10.0/LS-DYNA建立立-平轧制三维有限元模型,模拟了该粗轧机组的轧制过程,重点研究了在立-平轧制过程中不同形状的立辊对板坯横断面形状、边角部金属的流动和应力应变规律,同时研究了立-平调宽轧制中轧辊和轧件的温度场分布。着重通过运用重启动方法和显示动力学方法相结合的方式模拟了5道次可逆立-平轧制过程,模拟结果与现场实测值对比,误差均在允许范围内,说明该方法的合理性和可行性。通过数值模拟得到以下结论：1)当0<l/h<1.5时为厚件的轧制变形,由于受到外端刚性区影响,易出现双鼓形；而l/h>1.5时为薄件的轧制变形,主要受表面摩擦的影响,一般为单鼓形。孔型立辊能更有效的纠正双鼓变形,避免产生边部夹层；2)轧件的边角部金属在轧制过程中逐渐流动到轧件的上下表面；且在相同轧制工艺条件下,孔型立辊轧制的翻平量大于平立辊轧制的翻平量,且随着孔型内倒角半径的增加翻平量逐渐增大,横断面鼓形随之变小；3)轧件边角部的金属在轧制过程中一直处于低温、高应变和高应力的状态,并逐渐向板坯的宽度中心移动,原始边界和每道次生成的边界在轧件边部逐渐累积,最终有可能引起沿轧件的长度方向产生“黑线”等缺陷；4)立轧具有一定的修复微小缺陷的作用,从而改善和提高了带钢的边部质量。合理的设计立辊的形状和优化侧压制度,可以有效的提高产品的质量。更多还原

【Abstract】 To improve the precision of the width control and the rolling yield of the strip hot-rolling’s rough rolling units, and amend the product’s surface quality, this paper studies the deformation law of work-piece processed by rough rolling units. It focus on the analysis and comparison of the dog-bone material’s deformation condition during horizontal rolling which provides reliable basis for making reasonable technological procedure. The hot-rolling units’field condition of Meishan Steel Industry is quoted. And the seam-defect appears at the area which in the distance of 10mm-20mm to the plate edge of rough-rolling medium billet is studied. The ANSYS10.0/LS-DYNA finite element software is used to establish the Vertical-Horizontal rolling’s three-dimensional finite element model. The rolling process is simulated, the main part of this paper are the effection of blank transverse shape caused by different shapes of vertical rolls; the flow law of the corner and edge metal; the transformation law of stress and strain and temperature filed distribution of rolled piece and roll. This paper numerically simulated the five-pass reversible V-H Rolling process by using explicit dynamic method and restart method. Contrasted simulation results with field test data the error is all in the limit of tolerance which shows the rationality and feasibility of this method. Outcomes show the following results:1) When 0<l/h<1.5, it’s thick piece, with the effect of the external rigid area, the workpiece appears to be twin drum. When l/h>1.5, it’s thin piece, the main effect is caused by surface friction, appears to be single drum. And it also shows that the groove vertical rolls can corret twin drum so that avoiding marginal interlayer.2) We found the metal of corner and edge gradually flowed to the upper and nether surfaces; and on the same rolling process conditions, the value of side tumbling on groove vertical rolling more than the value of side tumbling on flat vertical rolling, and the value of side tumbling increases while the drum of transversal profile decrease with the increasing of the groove fillet radius.3) During rolling process, the corner and edge metal is in the status of low temperature, high strain and high stress, and gradually flow to the width centre portion of blank, original boundary and new boundaries generated in each pass gradually cumulate on the edge of the workpiece, which may bring the seam-defect along the length of the workpiece.4) Vertical roll has the ability to repair minimal defects, so that it can increase and improve the quality of the edge of strip steel. Reasonable design of the vertical roll shape and optimization of the side pressure system can effectively improve the quality of the product.更多还原