【作者】 刘彬彬；

【导师】 钟毅； 王华昆；

【作者基本信息】 昆明理工大学 ， 材料学， 2003， 硕士

【摘要】 随着电线电缆技术的发展，对其在高导电性、钎焊性、耐蚀性、重量轻及强度高方面提出了越来越高的要求，传统的单一材料难于满足这些需求。多层金属复合线材综合了多种金属的优越性能，形成高性能材料，并且还可以节约金属。 本论文通过对双金属连续挤压包覆技术的有限元分析和理论分析的研究，以DEFORM为数值模拟平台(清华大学合作)，对双金属连续挤压包覆的不同参数下的温度场，等效应力场，等效应变场，等效应变率场，静水压力场，速度场进行了模拟，获得了在双金属连续挤压包覆过程中，各工艺参数主要影响规律；实现了模具的快捷化设计。这些结论同样适用于多金属连续挤压包覆生产多材料复合线材。 通过数值模拟的结果的研究表明：CONCLAD过程是一个非常复杂的过程，通过数值模拟的结果来看，复合变形区长度是设计，装配时的一个重要参数，应把复合变形区长度调整到一个适当的值，否则过短则无法实现包覆，出现包覆材“包套”的现象，过长则出现“断线”的问题；随挤压速度的提高，挤压温度的降低，坯料与芯线的摩擦系数增加，会出现断线的问题。挤压速度的增加会带来坯料温度的增加，温度的升高会补偿挤压速度的增加所带来的断线的可能。从三维有限元模拟的结果来看，坯料先充满挤压腔，之后进入包覆腔。等效应力与等效应变的集中区在定径带入口处。在挤压包覆腔的底部形成死区。通过数值模拟可以验证中性点的存在，并且在不同模具结构条件下，给出中性点的位置，与双金属成形极限图所得的结论具有一致性。更多还原

【Abstract】 As the development of electrical wire and cable technology, the higher demand is required in the aspects of high electric conductivity, soling, corrosion-resisting, high strength etc. the traditional single material hardly meets the need of these demands. Multi-material cladding wire gathers the advantages of internal elements, and become the high performance material, which can economize the metal.The dissertation is carried out by DEFORM on the basis of the analysis of the theory and FEM for the double-material CONCLAD processing, which has simulated the temperature field, effective stress field, effective strain field, mean stress field, and velocity field under condition of the various parameters, by which the rules that can realize the rapid design for the dies are got. What is more, the conclusions achieved also fit the multi-material CONCLAD processing.The results show that the height of clad forming zone is a key parameter to the design of die and fitting. The increase of the die height will result in the core rupature. The change of the die angle has little influence on the CONCLAD processing, and the mean stress, effective stress and stain are of no changes nearly. The result of increasing the extrusion temperature by changing the dimensions of the die is not in evidence. The extrusion velocity is also an important parameter for the CONCLAD processing. If the only velocity is considered, the increase of the extrusion velocity can lead to the core rupature, and the decrease to the decrease of the product efficiency. Increasing the billet temperature will prevent the core rupature, but the high temperature will decrease the mean stress and affect the quality of the fuse between the surfaces. The high friction coefficient will not only increase the mean stress, but also increase the effective stress. High friction coefficient can lead to the core rupature. Increasing extrusion velocity can bring the increase of billet temperature, which can compensate the problem of core rupture caused by feed velocity increasing. In this case, increasing feed velocity will not result the core rupture. In the view of the three dimensions FEA, the stress and strain centralize the entrance of bearing belt, and the dead zone is formed in the bottom cladding chamber. The result by the simulation agrees with the one of the experiment, such as core rupature, sheath and the theory of the neutral point. The influence of the height of the cladding deform zone to CONCLAD, and the influence of the friction coefficient to the CONCLAD accord with the other theory such as the diagram of forming limit in CONCLAD.更多还原