电沉积镍涂层的冲压成形极限右边分析与预测

基于材料实际应力应变曲线,运用多项式拟合法计算了涂层薄板的成形极限。对冲压过程中涂层薄板的等效应力和等效应变进行了推导,通过求解Swift分散颈缩失稳条件的非线性方程得到了冲压成形极限的第一主应变,获得了涂层薄板的成形极限右边曲线。计算发现,涂层厚度、基体厚向异性指数对涂层薄板的成形极限有显著影响,镍涂层的成形性能低于钢基体的成形性能,并且基于实际应力应变曲线的涂层薄板的成形极限低于传统方法计算的成形极限。

Analysis and Prediction for Forming Limits of Electrodeposited Nickel Coating in the Right Region

This paper analyzed the forming limits of coating sheet based on actual materials’ stress-strain curves.The effective stresses and effective strains in the components were deduced during forming process,and forming limit strains were obtained by solving nonlinear equation of the Swift diffuse necking conditions.Polynomials were used to fit the experimental stress-strain data in the coating and substrate.Research shows the forming limit curves based on polynomials fitting are lower than that from the Hollomon formulae,and the coating thickness and substrate anisotropy have great effect on FLD.The forming performance of the electrodeposited nickel coating is lower than that of the low carbon steel substrate.