【作者】 王磊；

【导师】 刘化民；

【作者基本信息】 吉林大学 ， 材料加工工程， 2012， 硕士

【摘要】 辊锻是采用轧辊作为工具，通过轧制工艺生产锻造工件的方法，它具有设备重量轻、驱动功率小、成形生产效率高及锻件尺寸稳定等一系列优点。随着计算机有限元软件的不断发展，传统的经验方法已逐步被代替。采用有限元模拟厚壁空心件的辊锻过程，对优化辊锻模的设计、控制空心辊锻件质量、揭示辊锻过程金属流动规律、弥补空心件辊锻理论的空白及促进辊锻技术在厚壁空心件上的应用具有重要意义。由于厚壁空心件辊锻理论的空白，且现有实心件辊锻理论对空心件辊锻模设计只能起到指导作用，因此设计的空心件辊锻模与实际情况会有较大误差。这不仅延长现场调试的时间，还不可避免地浪费大量的人力物力。借助DEFORM-3D有限元软件模拟厚壁空心件辊锻全过程，分析空心件的金属流动规律、各道次典型截面的等效应变场分布、温度场分布、管壁增厚情况等，揭示辊缝、摩擦系数、温度及压下量对空心件辊锻的影响规律，均具有节约成本，缩短试制周期，提高效率等优点。根据现有辊锻工艺确定原始管坯的尺寸与辊锻道次、选择型槽系、设计孔型等。通过CATIA软件对辊锻件和扇形辊锻模进行三维实体造型，建立厚壁空心件辊锻的有限元模型，通过两道次辊锻和一次整形完成厚壁空心件的辊锻,并根据模拟结果，修改辊锻模。本文对厚壁空心件辊锻过程模拟中的定位、接触、咬入、约束和增加整形辊锻等问题进行系统的分析与研究，这对空心件辊锻理论的建立具有重要价值。通过与实心件的辊锻模拟结果对比，揭示壁厚对延伸量和展宽量影响规律，讨论摩擦系数对实心件与空心件辊锻的影响。结合空心辊锻件实验产品，对比产品的几何尺寸、前滑值、管壁增厚情况、缺陷种类及产生缺陷机理，表明模拟结果与真实实验结果基本一致，证明该有限元模型建立的准确性、可信性，论文针对辊锻过程中出现的弯曲、飞边、圆截面成形质量差等提出改进措施，并利用改进后的孔型进行了模拟研究.数值模拟结果表明：增加整形道次后，圆截面椭圆度基本消失，有效地改善了锻件的成形质量，对指导实际厚壁空心件辊锻生产提供了参考。更多还原

【Abstract】 Roll-forging is a way to produce the forging piece by means of rollers, and it presents a seriesof advantages, such as light weight of equipment, low driving power, high production efficiencyand stable size of forging piece. With the increasing development of FEM software, traditionalmethod has gradually been replaced. Making use of FEM to simulate roll-forging forthick-walled hollow part, it is very beneficial for optimizing the rolling die design, controllingthe quality of hollow part, revealing metal flow law during roll-forging process, making up forthe theory blank of roll-forging for hollow part and improving the roll-forging technologyapplied in hollow part.Because roll-forging theory of thick-walled hollow part is blank and existing roll-forgingtheory of solid part just plays a role in guiding rolling die design，the gap between designed diesand actual ones is bigger. It not only extends the on-site commissioning time, but also inevitablywastes a lot of manpower and resources. By means of DEFORM-3D to simulate the wholeroll-forging process for thick-walled hollow piece including metal flow law of hollow part、equivalent strain field distribution of typical sections、temperature field distribution、situation ofwall thickening、 influence law of gap、friction coefficient μ、temperature and reduction onroll-forging for hollow part，and it can save cost, reduce trial cycle and improve efficiency.Based on existing roll-forging process, not only the size of original tube blank and roll-forgingsteps are determined, but also the grooves are selected and rolling passes are designed.Roll-forging part and fan-shaped dies are modeled by CATIA, roll-forging FEM for thick-walledhollow part is set up, and roll-forging for thick-walled hollow part is finished through two stepsand one step for reshaping.At the same time, rolling dies are modified according to thesimulation results. This paper systematically analyzed and studied positioning, contact, bite,constrained conditions and pass increased to shape during the thick-walled hollow roll-forgingprocess simulation, and all the results are of great value to establish roll-forging theory of the hollow part.Compared with simulation results of roll-forging for solid pieces, influence law of wallthickness on elongation and width is revealed, and effect of friction coefficient μ on roll-forgingfor solid part and hollow part is discussed. According to experimental product of hollow part,geometric sizes、forward slips、wall thickening conditions、defect types and mechanisms ofemergence of the defects of two products are coincident by contrast, accuracy and reliability ofFEM establishment are proved. In the paper, improving methods of defects are presented, androll-forging process for hollow part is again simulated after rolling dies are modified. Thesimulation results indicate after increasing the roll-forging step, ellipse degree of circular sectionhas disappeared, efficiently improved quality of the forging piece, and provided a reference forguiding the actual roll-forging for thick-walled hollow part.更多还原