【作者】 仉志强；

【导师】 宋建丽；

【作者基本信息】 太原科技大学 ， 材料加工工程， 2014， 博士

【摘要】 厚度>100mm的特厚板卷焊筒节是制造大型中高压厚壁容器和反应器的关键部件。近年来，在石油、化工、核电、造船等行业市场刚需与“十二五”重大装备国产化方针的合力推动下，重型三辊卷板装备研制和大型厚壁筒节成形工艺控制成为卷板行业研究重点。由于特厚板弯曲机理复杂、弯卷工艺影响因素多，因此，在重型卷板机设计阶段和厚壁筒节弯卷成形阶段存在诸多问题，如特厚板弯矩计算误差大、人工操控依赖度大、弯卷道次多和效率低等。本文在山西省科技重大专项——重型三辊卷板成套设备研发（NO.20111101032）的资助下，以提高重型卷板装备设计水平与厚壁筒节弯卷成形控制水平为目标，采用理论建模、有限元模拟和实验研究相结合的方法，对特厚板三辊弯卷成形工艺进行了系统研究；建立了特厚板弯矩模型、三辊预压弯和滚弯模型，制定了特厚板弯卷成形工艺规划方案，确定了工艺参数算法并提出了厚壁筒节成形质量控制策略。论文主要研究内容包括：1.阐述了大型厚壁中高压容器和重型卷板机的市场背景和研制现状；对厚壁卷焊筒节和重型三辊机的关键工艺参数、多辊弯卷成形理论模型和板材弯卷成形有限元模拟关键技术及国内外研究现状进行了分析和评述。2.以Q235特厚板为研究对象，在厚向不同位置截取圆棒拉伸试样并进行静拉伸试验，得到了特厚板厚向强度和塑性分布规律；建立了厚向强度非均匀分布的特厚板纯弯曲工程模型及回弹模型；研究了特厚板弯曲机理、弯矩影响因素及其影响比重随曲率的变化规律。3.在考虑厚向强度分布、材料硬化特性、回弹、板-辊接触点偏移等因素的基础上，建立了特厚板三辊滚弯精确模型，制定了上辊压下量与滚弯半径的工艺曲线及近似公式；分析了厚向强度分布和下辊中心距等对滚弯成形力学参数和几何参数的影响规律。4.建立了特厚板三辊预弯成形精确模型，获得了上辊压下量与预弯角工艺曲线及理论计算方法；分析了厚向强度分布等对预弯工艺参数的影响，并优化了预弯工艺；采用中厚板不对称压弯试验验证了所建预弯模型的正确性。5.将特厚板单道次弯卷成形流程规划为多个工步和动作步，建立了工作辊速度算法；针对重型卷板机的上辊驱动系统的严重时滞特性，建立了以分段恒速为特点的低阶速度响应算法；采用有限元方法对单道次弯卷成形和回弹过程进行了数值模拟；研究了悬置板材的动态惯性、卷板速度、滚弯道次和上辊变形对厚壁筒节质量的影响。6.建立了多道次滚弯成形控制算法；采用四种厚壁筒节的多道次滚弯成形模拟结果验证了新算法的精度和适用性；分析了厚壁筒节多道次滚弯成形质量的影响因素，提出了相应的控制策略。更多还原

【Abstract】 Cylindrical segment with a thickness of more than100mm is one of the keycomponents of large, medium-high pressure, thick-wall vessels and reactors. Inrecent years, the research and production (R&P) of heavy three-roller bendingequipment and the forming process control of cylindrical segment have becomethe key research points in the field of plate bending, under the promoting ofmarket requirement of oil, chemical, nuclear power, shipping industries, etc. andthe “Twelfth Five Plan” policy on the demostic of heavy machine equipments.Because the mechanism of super-thick plate bending is complexy, and there aremany factors influencing the bend-rolling process, many problems exist in thedesign of heavy bender and the bend-rolling forming of thick-wall cylindricalsegment, such as obvious calculation error of thick plate bending moment,excessive dependence on manual operation, more roll-bending passes and lowproduction efficiency, etc.. Under the financial support by the major scientificproject of shanxi province (Research and Development of heavy three-rollerbending equipment NO.20111101032), in this paper, aims to prompt the designlevel of heavy bending equipment, the bend-rolling forming process ofsuper-thick plate was systematically studied with combination methods oftheoretical modeling, finite element simulation and experimental study. Thebending moment model, prebending and roll-bending models of super-thickplate were build up, planning pattern and parameter algorithm of bend-rollingforming process were proposed, and effective control strategies of improving theforming quality of cylindrical segment were proposed.The main contents are as follows:1. The marketing background and R&P status of large-and-thick vessel andheavy three-roller bender was discussed. The key parameters of thick-wallcylindrical segment and heavy three-roller bender, the theoretical model ofmulti-roller bend-rolling forming process, and FEM simulation key technologiesand research status at home and abroad of plate bend-rolling forming wereanalyzed and reviewed. 2. Q235thick plates were selected as research objects, tensile testing ofbars cut from different positions through the plate thickness were carried out,strength and ductility distribution through the thickness of the super-thick platewas obtained. The engineering bending model and springback model ofsuper-thick plate considering nonuniform strength distribution through thicknesswere built up. The bending mechanism of super-thick plate, factors influencingthe bending moment and its variation rules with relative curvature were studied.3. The precise three-roller bending model of super-thick plate was set upconsidering strength distribution through thickness, material hardening property,springback, and plate-roller contact shift, etc.. The relationship betweentop-roller displacement and roll-bending radius and the approximation formulawas obtained, and the effect of strength distribution and bottom-rollers distance,etc. on the mechanical and geometrical parameters was analyzed.4. The precise model of super-thick plate prebending was proposed. Therelationship between top-roller displacement and prebending angle and thetheoretical model was obtained. The influence of strength distribution throughthickness on the prebending process parameters was analyzed, and theprebending process was optimized. The presented prebending model wasverified by the asymmetrical bending test of moderate-thick plate.5. The single-pass bend-rolling forming process of super-thick plate wasplaned into multiple working steps and movement steps, and the velocityalgorithm of the work roller was presented. According to the obvious time-lagproperty of the top roller driving system, the speed control algorithm oflow-order response was presented with a characteristic of section constant speed.The single-pass bend-rolling forming and springback process was simulatedwith finite element method. The effect of plate dynamic inertia, roll-bendingvelocity and top roller deformation on the bending quality of thick-wallcylindrical segment was studied.6. The control algorithm of multi-pass roll-bending forming process ofsuper-thick plate was set up. The accuracy and availability of the new algorithmwas verified with the simulation result of multi-pass roll-bending forming of four kinds of thick-wall cylindrical segments. Factors influencing the multi-passroll-bending quality of thick-wall cylindrical segment were analyzed, andcorresponding control strategies were proposed.更多还原