GH605板料成形极限影响因素分析

Analysis of influencing factors on forming limit of GH605 sheet metal

板料成形极限图是用来评价板料成形性能的综合指标。通过胀形数值仿真得到0.2 mm和2.5 mm厚的三种不同热处理条件下GH605板料的成形极限曲线。通过实验对比验证0.2 mm厚的三种料的成形极限计算结果,结果表明仿真结果可以较好地反映实验结果。从材料性能差异的角度,分析研究加工硬化指数(n值)和厚向异性指数(r值)对成形极限的影响。综合仿真与实验结果表明,两种经过水冷固溶的板料成形性能显著优于经过退火处理的板料,成形极限曲线随着n值和r值的增大而升高,且n值对成形极限曲线的影响比r值的影响更显著。通过数值模拟建立的材料成形极限图,可为材料研制和工艺选材提供理论依据。

Sheet metal forming limit diagram(FLD)is a comprehensive index used to evaluate sheet metal formability.In this paper,the forming limit curves of GH605 sheet materials with 0.2 mm and 2.5 mm thickness under three different heat treatment conditions were obtained by numerical simulation of bulging.Then,the simulated forming limit results of the three materials with 0.2 mm thickness were compared with the experimental results.The results show that the simulated FLDs can be in good agreement with the experimental FLDs.The influences of work hardening index(n value)and anisotropy index(r value)on the forming limit are analysed from the view of material property difference.The comprehensive simulated and experimental results show that the formability of the sheets after the two kinds of solution treatment is significantly better than that of the annealed sheets.The forming limit curve increases with the increase of n value and r value,and the influence of n value on the forming limit curve is more significant than that of r value.The forming limit diagram established by numerical simulation can provide a theoretical basis for material development and process selection.