Hybrid-Forging: Combined Forming and Joining of Sheet and Bulk Metal

轻量化结构部件通常是为装配和功能的需要而设计的。它们通常有大块元素和薄片元素。如今，这些元件是单独制造的，然后在附加的工艺步骤中连接起来，例如通过焊接或螺钉连接。在第一个资助期，对混合锻造的基本原理进行了模拟和实验研究。混合锻造是在一个步骤中锻造大块零件，成形钣金零件和连接这些零件。在三个模型实验（HS1至HS3）中，利用有限元模拟和实际实验对材料的键合机制和正锁进行了评估。研究了变形、板料温度、摩擦等参数对实体与板料连接质量及板料厚度的影响。在模型实验HS1和HS2中实现了部分材料键合。在模型实验HS3中，实现了正锁定。然而，板材部分凸起，无意中弯曲，厚度减少。本研究项目第二阶段的目标是在第一阶段的基础上开发混合锻件。应减少板材的变形（胀形、弯曲、板材减厚），提高连接质量。通过使用强度更高、厚度更大的板材，以及使用压边器来减少变形。连接质量是提高了几何强迫相对运动的大块相对于钣金元件。将开发一种由普通金属板材和锻造材料制成的可变元件以及变形过程的示例性混合锻造部件。此外，该示例部件应说明不同的制造操作，钣金和大块元件的成形以及元件的连接（正锁定和材料粘合），并允许研究成形和连接操作的相互作用。在此基础上，设计了成形工具进行了实验测试，并对复合零件的金相性能和力学性能进行了研究。随着本研究的深入，结构构件设计的可能性得到了扩展，构件的轻载荷区域可以用钣金元件代替，或者构件的部分可以用大块元件加固。由于整体成形和钣金成形同时进行，与传统工艺链相比，包括连接在内的工艺链缩短了。

Lightweight structural components are often designed for the needs of assembly and function. They often have bulk- and sheet-elements. Nowadays, these elements are separately manufactured and subsequently joined in additional process steps, for example by welding or a screw connection.In the first funding period a simulative and experimental study of the basics of hybrid forging was investigated. Hybrid forging is the forging of bulk parts, the forming of sheet metal components and the joining of these parts in a single step. Material bonding mechanisms and positive locking have been evaluated in three model experiments (HS1 to HS3) using FE-simulations and practical experiments. The influence of the parameters deformation, temperatures of sheet metal and bulk elements, and the friction was investigated on the quality of the joint between solid and sheet metal element and the sheet thickness. In model experiment HS1 and HS2 partially a material bonding was achieved. In model experiment HS3 a positive locking was achieved. However, the sheets bulged partially, were bent unintentionally and were reduced in their thickness.The aim of the second period of this research project is the development of the hybrid forging based on the insights developed in the first period. The deformation of the sheet (bulging, bending, and sheet thickness reduction) shall be reduced and the quality of the joining shall be increased. The deformation is to be reduced by sheet materials with a higher strength and greater thickness, and by the use of blank holders. The joining quality is enhanced by a geometrically forced relative motion of the bulk in relation to the sheet metal element. An exemplary hybrid forging part with variable elements made of common sheet metal and forging materials as well as the deformation process will be developed. Furthermore, this example part should illustrate the different manufacturing operations, forming of sheet metal and bulk elements and joining (positive locking and material bonding) of the elements and allow a study of the interaction of forming and joining operations. Furthermore, forming tools are designed for experimental tests and metallurgical and mechanical properties of the hybrid parts are investigated, especially the joining areas.With the insight gained in this research the possibilities of designing structural components are extended that lightly loaded regions of a component can be substituted by sheet metal elements or elements can partially be reinforced by bulk elements. Due to the simultaneous bulk and sheet metal forming including joining the process chain is shortened compared to conventional process chains.