Passive granular medium-based tube press hardening

被动颗粒介质基管压制硬化

• 批准号: 427196185
• 负责人: Professor Dr.-Ing. A. Erman Tekkaya
• 金额: --
• 依托单位: Institut für Umformtechnik und Leichtbau (IUL)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/427196185?language=en
• 关键词: Passive; granular; medium; based; tube

The aim of the project is the investigation of the passive granular medium-based tube press hardening to facilitate the manufacturing of profile components with an unlimited length. The common process for hot forming of profile components is based on gaseous media. A problem is the compressibility of the gas, so that high forming pressures are associated with a high-risk potential and limit in the stroke rate due to the pressure build-up time.An alternative are granular media, which allow the press hardening process of steel pipes by high pressure resistance and temperature stability. In the case of active granular medium-based tube press hardening, the forming force is generated by an axial punch insertion into the pipe end and transferred to the component via the granules. However, due to the internal friction, the granule column does not behave hydrostatically. This feature leads to the limitation of the producible pipe length, the achievable expansion and formability of small radii. In order to remove these significant restrictions and to achieve the ease of application, the passive granular medium-based tube press hardening has to be researched. In this process principle, the forming force is generated by closing the forming die. By the lateral pressure build-up not only the limitation of the tube length is removed, but also the attainable strain paths and profile shapes are extended by the compression of the tube cross-section.To achieve the project objective, the influence of the parameters such as e.g. the geometric conditions, the kinematics, the granular filling and the temperature control will be taken into account. Based on this, the pressure and temperature distribution will be analyzed, which influence the strains and mechanical properties. Accordingly, process limits and a working area have to be determined.The project starts with the characterization of the ceramic beads and the quartz sand as forming media, the 22MnB5 as a pipe material and their interactions. With this knowledge, the project contains furthermore the process design and the resulting product properties. In addition to the numerical simulation, an analytical model is necessary to determine the pressure and temperature distribution in the granular medium and the pipe component. The theoretical investigation also includes the evolution of the microstructure, so that depending on the process conditions components of different strength can be obtained. For validation, different variants are studied in an experiment, such as the two-dimensional forming without granular flow in the axial direction or the forming with induced axial flow for producing profiles with graded cross-sectional area. In addition, the new tool technology will be developed in terms of the heat supply of the pipe component by shunt heating, so that the in-situ heating process takes place directly after the granular filling and insertion into the tool for a maximum effective cooling rate.

该项目的目的是研究被动颗粒介质基管压制硬化，以促进无限长度型材部件的制造。型材热成形的常用工艺是基于气态介质。一个问题是气体的可压缩性，因此高成型压力伴随着高风险，并且由于压力建立时间而限制了冲程速度。另一种选择是颗粒介质，它通过高耐压性和温度稳定性实现钢管的压制硬化过程。在基于活性颗粒介质的管压制硬化的情况下，成形力通过轴向冲头插入管端产生，并通过颗粒传递到部件。然而，由于内摩擦，颗粒柱不表现流体静力学。该特征导致可生产的管长度、可实现的膨胀和小半径的可成形性的限制。为了消除这些重要的限制，并实现易于应用，被动颗粒介质为基础的管压制硬化的研究。在该工艺原理中，成形力通过闭合成形模具而产生。通过侧向压力的建立，不仅消除了对管道长度的限制，而且通过压缩管道横截面来扩展可达到的应变路径和轮廓形状。为了实现项目目标，将考虑几何条件、运动学、颗粒填充和温度控制等参数的影响。在此基础上，分析了压力和温度分布对应变和力学性能的影响。因此，必须确定工艺限制和工作区域。该项目首先对作为成型介质的陶瓷珠和石英砂、作为管道材料的22MnB5及其相互作用进行表征。有了这些知识，该项目还包括工艺设计和由此产生的产品特性。除了数值模拟之外，还需要一个分析模型来确定颗粒介质和管道组件中的压力和温度分布。理论研究还包括微观结构的演变，以便根据工艺条件可以获得不同强度的组件。为了验证，在实验中研究了不同的变体，例如在轴向方向上没有颗粒流的二维成形或用于产生具有梯度横截面积的轮廓的诱导轴向流的成形。此外，还将开发新的工具技术，通过分流加热为管道组件提供热量，以便在颗粒填充和插入工具后直接进行原位加热过程，以获得最大的有效冷却速率。