【作者】 冷艳；

【导师】 景作军；

【作者基本信息】 北方工业大学 ， 机械电子工程， 2003， 硕士

【摘要】 传统的对铝型材挤压工艺的研究，主要通过实验的方法获得挤压过程中的工艺参数。随着计算机技术的发展，CAD／CAM／CAE技术在铝加工中有了越来越广泛的应用，人们也开始使用数值模拟技术来研究铝型材的挤压工艺。 在常规的铝及铝合金热挤压过程中，金属的温度和变形是很不均匀的，这将导致产品的尺寸、形状、组织和性能等质量方面的缺陷。随着挤压技术的发展和对挤压工艺的深入研究，人们逐渐认识到等温挤压对限制及消除这些质量缺陷是一种较理想的挤压方法。实现等温挤压有多种方法，文中通过对等速、变速挤压方式实现等温挤压做了相关研究。但由于铝型材挤压工艺的复杂性，等温挤压技术的研究还主要集中在简单铝型材的基础上。 本文以铝棒材为研究对象，建立了考虑热传导、对流换热、摩擦生热和塑性功等多种边界条件的热-力耦合温度场的有限元模型。使用MSC.Marc有限元分析软件，选用刚塑性有限元法和平面轴对称单元，通过对铝棒材等速挤压和变速挤压的数值模拟，给出了不同速度下出口温度与挤压行程的关系。通过对等速挤压的数值模拟，可以得到挤压过程中的温升，对于给定坯料温度和出口温度的挤压过程，提供了挤压速度的选择依据。而对变速挤压的模拟则说明，通过建立合理的挤压速度规范，则同样可实现等温挤压。 模拟计算的结果可用于优化棒材挤压工艺参数，从而可以提高生产效率，并可获取组织、机械性能较为一致、表面质量良好的挤压型材，对实际生产起到的一定的指导作用。更多还原

【Abstract】 In conventional studies on the Aluminium extrusion process, extrusion technics is often determined by experiment. At present, with the development of computer technology, CAD/CAM/CAE are widely introduced into the manufacturing industry and researchers tend to use numerical simulation method to study the extrusion technics.During conventional hot extrusion processes, temperature and distortion of the billets change unevenly, so the dimension, shape, organization and capability of the profile will be deterioration. With the development and study of the extrusion technology, people gradually realize that isothermal extrusion technology will eliminate these quality limitations. There are many ways to realize isothermal extrusion. In this paper, isothermal extrusion which used variable speeds is studied. But the researches mainly focus on those relatively simple-shaped workpieces due to the complexity of aluminium extrusion process.In this paper, the author founded a model which consider of heat conduction, convection, and heat generation due to plastic work and friction. Using the rigid-plastic finite-element method and plane axisymmetric element, the model is capable of simulating the hot extrusion with constant and variable speeds. The temperature distribution and the speed effects in hot extrusion are predicted in detail by the proposed numerical model. The results show that reasonable speed criterion will realize approximately isothermal extrusion.The research proves that the results of the numerical simulation could optimize the parameters of the extrusion technics, sequentially the productivity will be improved greatly. The proposed numerical simulation has been demonstrated to be a powerful tool for the design of hot extrusion processes.更多还原