Baumann Markus, Selbmann René, Milbrandt Matthias, Kräusel Verena, Bergmann Markus
Institute for Machine Tools and Production Processes, Chemnitz University of Technology, D-09126 Chemnitz, Germany.
Fraunhofer Institute for Machine Tools and Forming Technology IWU, D-09126 Chemnitz, Germany.
Materials (Basel). 2021 Apr 23;14(9):2157. doi: 10.3390/ma14092157.
After conventional forming processes, the residual stress distribution in wires is frequently unfavorable for subsequent processes, such as bending operations. High tensile residual stresses typically occur near the wire surface and normally limit further processability of the material. Additional heat treatment operations or shot peening are often used to influence the residual stress distribution in the material after conventional manufacturing, which is time- and energy-consuming. This paper presents an approach for influencing the residual stress distribution by modifying the forming process, especially regarding die geometry. The aim is to reduce the resulting tensile stress levels near the surface. Specific forming elements are integrated into the dies to achieve this residual stress reduction. These modifications in the forming zone have a significant influence on process properties, such as plastic strain and deformation direction, but typically do not influence product geometry. This paper describes the theoretical approach and model setup, the FE simulation, and the results of the experimental tests. The characterization of the residual stress states in the specimen was carried out through X-ray diffraction using the sinΨ method.
在传统成型工艺之后，金属丝中的残余应力分布通常不利于后续工艺，如弯曲操作。高拉伸残余应力通常出现在金属丝表面附近，并且通常会限制材料的进一步加工性能。在传统制造之后，通常会采用额外的热处理操作或喷丸处理来影响材料中的残余应力分布，这既耗时又耗能。本文提出了一种通过修改成型工艺来影响残余应力分布的方法，特别是关于模具几何形状。目的是降低表面附近产生的拉伸应力水平。将特定的成型元件集成到模具中以实现这种残余应力的降低。成型区域的这些修改对工艺性能有重大影响，如塑性应变和变形方向，但通常不会影响产品几何形状。本文描述了理论方法和模型设置、有限元模拟以及实验测试结果。通过使用sinΨ方法的X射线衍射对试样中的残余应力状态进行了表征。
