成形-相変態連成CAEによるホットスタンプ部材の形状予測

Abstract

The hot stamping method is established for manufacturing high-strength automotive parts with good shape fixability. Recently, the hot stamping method has been applied to higher performance parts with tailored properties. CAE is indispensable in designing such parts. For designing hot-stamped parts, the forming simulation must be coupled with thermal analysis considering the temperature effect on formability. The final shape need not necessarily be predicted because of its good fixability. However, in high-performance parts with tailored properties, it is important to predict how the final shape is affected by phase transformation. To predict the final shape of hot-stamped parts, a CAE method that takes into account phase transformation effects has been developed. The accuracy of the calculation of the final shape by the CAE method was investigated. Hot-stamping experiments were carried out to obtain parts of different shapes by cooling control, and the CAE analysis of the final shape for each experimental condition was conducted. It was clarified that the final shape was varied by changing the cooling process, and that the results of CAE including phase transformation were in good agreement with the tendency of shape change in cross section.