【作者】 刘剑；

【导师】 李国禄；

【作者基本信息】 河北工业大学 ， 材料加工工程， 2003， 硕士

【摘要】 在中国巨力集团公司实际生产中，钢丝绳套冷压模具凹模大量早期失效使产品质量不能保证、成本增加。根据巨力集团要求，本文主要针对冷压凹模早期失效进行分析研究并提出解决方案。在深入现场认真调查研究的基础上，抽测一定数量的失效凹模进行分析研究，首先利用扫描电镜对断口的形貌及属性进行分析，并对凹模本体的化学成分、力学性能、金相组织进行了分析研究，结果表明：失效冷压凹模的断口属于典型的疲劳断口，存在瞬时断裂区；模具本体材质符合国家CrWMn材质的标准，其力学性能和金相组织也基本符合要求。 通过对国内外模具早期失效研究文献的综合分析，可知大多数冷压模具早期失效是由于模具表面产生疲劳裂纹所引起的，而模具疲劳裂纹的发源地往往是结构设计缺陷造成的模具表面最大应力集中点。本文应用传统的强度理论和现代有限元分析软件NASTRAN 相结合的方法对钢丝绳套冷压模具原设计的结构强度进行了有限元仿真计算，指出了厂方冷压模具原结构设计缺陷是凹模早期失效的主要原因，进而采用不同的结构设计参数进行有限元优化仿真，对比冷压模具应力和应变云图，优选出最佳结构优化设计方案。根据模具材质分析和结构优化计算结果，为厂方提交了优化后的模具设计方案和热处理工艺改进意见，厂方按照上述方案制造了8套钢丝绳套冷压模具，在实际生产中进行装机试验，结果表明：冷压模具凹模的使用寿命由原来使用寿命2000～2500模次提高到5000～6000模次左右，使模具寿命提高了1.5倍左右。 综上所述，采用模具虚拟仿真制造技术对钢丝绳套冷压模具进行实际工况下结构强度有限元仿真失效分析计算，可以准确地判断模具早期失效的结构缺陷，大幅度缩短了模具的优化设计试验周期和降低试验费用，对于其他类型模具失效分析和优化设计具有一定的借鉴意义。更多还原

【Abstract】 Many steel rope jacket cold stamping concave dies failed at the early stage in the JuLi Group Company of China, resulting in poor face quality and high production cost. In this paper, the main research works have been focused on analyzing the failure reason of early failed dies and submitting the solution measurement for the requirement of the JuLi Group Company of China. On the basis of the careful investigation on the actual conditions, a number of early failed concave dies that were selected from the factory have been analyzed. Firstly, the fracture of the failed die has been observed. And the chemical composition, the mechanical properties and the metallographic structure have all been studied. It is evident as the fracture surface of all failed concave dies was typical fatigue fracture characteristics. The chemical composition, the mechanical properties and the microstructure of the concave die steel all accorded basically with the national standard of the CrWMn.After investigating the native and foreign literatures on the early failure analysis of the dies synthetically, it is evident as the main reason of the cold stamping dies early failure is because the fatigue cracks on the surface of the dies. The stress concentration point is usually the resource of the fatigue crack. In this paper, the finite-element model of the cold stamping die was created according to the original structural design and the actual load. On the basis of this, applying the NASTRAN software finished its structural strength finite-element simulation. Furthermore, defining the different structural parameters was also submitted to NASTRAN software to analyze strength. By contrast with the stress nephogram and the strain nephogram, the optimal structural design scheme was established. Basing on the results of the dies steel analysis and the die structural optimization calculation, the optimal scheme of the structure and the heat treatment have been submitted to the JuLi Company. The factory has produced eight series of the cold stamping die for the actual experiment. The result of the experiment is satisfaction to the factory. The service life of the steel rope jacket cold stamping die has been improved from 2000-2500 times to 5000-6000 times.Through this study, it was shown that using the virtual manufacturing technology for analyzing the early failure of the cold stamping dies was very effective. It can clearly find the structural mistakes of the failed dies. Also it can reduce the cost of the die optimization and shorten the experiment time. So this method can be used for reference to the other dies.更多还原