Failure Analysis Of Steel Rope Jacket Cold Stamping Die And Its Structural Finite Element Calculation

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.