【作者】 曹雪；

【导师】 樊志新； 宋宝韫；

【作者基本信息】 大连交通大学 ， 材料加工工程， 2008， 硕士

【摘要】 铜母线连续挤压技术与传统加工工艺相比,具有生产效率高、节能效果显著、无污染、产品长度不受限制和质量优良等优点,因此在实际生产中得到了广泛的应用。铜母线连续挤压变形过程极其复杂,坯料发生了极度的3D塑性大变形和剪切变形。变形过程的摩擦条件和材料温升速度、变形温度和变形抗力、金属受力状态和变形方式等因素决定了整个变形过程。若工艺参数和模具结构尺寸选择不当,易造成产品的弯曲、缺料等缺陷,模具也极易损坏。本课题通过理论计算对铜母线连续挤压变形过程力能等参数进行了分析,由此找到挤压力、能耗和温度与模腔结构参数之间的关系;采用有限体积数值模拟软件MSC.Superforge预测挤压过程可能出现的缺陷,及时调整工艺参数,提出改进方案。本文分为四部分:1.结合连续挤压技术与成形工艺特点,阐述了采用解析法和有限体积法对铜母线连续挤压扩展成形过程进行分析的必要性、可行性及优越性。2.通过对连续挤压几何模型合理简化和分区,对铜母线连续挤压变形过程力能进行了分析。根据功-热转化原理和实验测试,研究了各区变形力、能耗与变形温度的关系;分析了摩擦条件、产品宽厚和坯料直径对挤压力的影响;计算了铜母线连续挤压过程各分区的温度、能耗;考察了压实轮对坯料的压下力和挡料块承受的载荷。3.根据铜母线连续挤压成形的塑性变形特点,对大变形复杂成形过程的数值模拟选用有限体积法,介绍了塑性材料有限体积法的基本原理和求解方法。4.对扩展挤压成形过程的数值模拟结果进行了详细的分析。根据对坯料表面接触压力和金属流动速度场的分析,从改变金属在扩展模腔内的受力状态的角度出发,在不改变金属流动通道长度的前提下改变模腔结构,达到了均匀模口中心和两侧金属流动速度差的目的,改善了成形过程。本课题得到的结论可以为大尺寸铜母线的成形、模具的优化和大型挤压机的设计提供理论依据。更多还原

【Abstract】 Comparing with traditional manufacturing technique, continuous extrusion technology for copper bus bar has many excellences, such as high productivity, low energy consumption, no contamination, no restriction in product length and high quality, so it is widely used in production.Copper bus bar continuous extrusion deformation process far is very complex, and the billet endures fierce 3D plastic deformation and shearing deformation. Friction condition and temperature rising rate of material, deformation temperature and deformation resistance, the state of metal under force and deformation manner, etc. determine the deformation process. If the technique parameters and the die structure are not chosen correctly, many defects will be caused, for instance curling, cracking and lacking material of the products, and the dies will be also spoiled easily.The paper strives to analyze the parameters of force and energy of continuous extrusion process by theory calculation and finds the relationships between extrusion force, energy consumption, deformation temperature and the parameters of die chamber; and forecasts the defects existing in the extrusion process by FVM numerical simulation soft ware MSC. Superforge, to adjust technique parameters and put forward ameliorate projects.The main job of this thesis including the following four parts:1. Combining continuous extrusion technology with forming technical characteristics, the necessity, feasibility and superiority to simulate the continuous extrusion extending deformation process for copper bus bar with FVM are expatiated.2. By reasonably simplifying the geometry model of copper bus bar continuous extrusion and the division of forming zone, the parameters of force and energy were analyzed. According to the transform principle of heat-work combined with test, the formulas of forming force and energy consumption concerning deformation temperature in each sub zone are deduced; by programming calculation, analyized the effects of friction, product width and thickness and billet diameter on extrusion force; gained the energy consumption and temperature in every deformation sub zone; investigated the pressure acted on billet by coining roll and the deformation pressure endured by stationary abutment.3. According to the plastic deformation characteristics of copper bus bar, FVM and analytic method were used to analyze the large and complicated deformation process, and basic theory of elastic-plastic material FVM was introduced.4. The simulation results are analyzed detailedly. By analysizing contact pressure distribution of billet surface and the metal flow velocity field, the chamber design is optimized and the forming process of copper bus bar is improved with the simulation results. The conclusions of the paper could provide theory basis for the forming of large demension copper bus bar, the optimization of die chamber and the design of large model extrusion machine.更多还原