Residual stress-controlled incremental sheet forming of high-strength sheet metal components

增量金属板料成形（ISF）工艺适合于根据特定要求以小批量经济地制造部件。部件特性特别地由部件中的残余应力确定。该研究项目的目的是通过成形引起的残余应力来改善由高强度钢制成的部件的性能。通过成形过程以特定方式影响残余应力的潜力在以前的供资期间得到了证明。结果表明，ISF工艺参数直接影响变形机制的弯曲、剪切和法向应力分量，从而影响残余应力状态。在第二个资助期内，分析了通过形成诱导残余应力来实现部件性能的改善。工艺改进能够诱导更高的残余应力或将压缩残余应力转化为拉伸残余应力。第三个资助期的重点是预测在腐蚀性环境中连续运行时的部件性能改进和残余应力稳定性。在与佛吉亚Autositze GmbH的一个转移项目中，这些发现是根据工业要求转移的。为此目的，先前分析的材料被扩展到高强度双相钢和面向应用的几何形状用于工业用途。除了静态和循环载荷下的组件性能，对制造的组件的几何精度的影响进行了分析。一个概念与振荡的工具运动被施加到引入额外的近表面压缩残余应力关闭，并减少过程中的力量。应通过同时使用多个成形工具来缩短加工时间。

The incremental sheet metal forming (ISF) process is suitable to economically manufacture components in small batch sizes according to specific requirements. The component properties are particularly determined by the residual stresses in the component. The aim of the research project is to improve the component properties made of high-strength steel through forming-induced residual stresses. The potential of influencing the residual stresses in a specific way through the forming process was proven in the previous funding periods. It was shown that the process parameters of ISF directly influence the deformation mechanisms bending, shearing and normal stress component, which effects the residual stress state. In the second funding period the achievable improvement of the component properties by forming induced residual stresses was analyzed. Process enhancements enable an induction of higher residual stresses or an inversion of compressive to tensile residual stresses. The third funding period focused on the prediction of the component property improvements and the residual stress stability under continuous operation in a corrosive environment. In a transfer project with Faurecia Autositze GmbH these findings are transferred under industrial requirements. For this purpose, the previously analyzed materials are extended to high-strength dual-phase steels and application-oriented geometries for an industrial use. In addition to the component performance under static and cyclic loads, the influence on the geometrical accuracy of the manufactured components is analyzed. A concept with an oscillating tool movement is applied to introduce additional near-to-surface compressive residual stresses close and reduce the process forces. A reduction of process time should be achieved by the simultaneous use of multiple forming tools.