Setting an ultrafine grain at forged preforms by using cross wedge rolling

通过楔横轧在锻造预成型件上设置超细晶粒

• 批准号: 410149732
• 负责人: Dr.-Ing. Malte Stonis
• 金额: --
• 依托单位: Institut für Umformtechnik und Umformmaschinen (IFUM)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/410149732?language=en
• 关键词: Setting; ultrafine; grain; forged; preforms

Preforms produced by cross wedge rolling are used for a variety of parts by the forging industry. They are characterized by a low amount of surplus material. Compared with ECAE cross wedge rolling is implemented and established in industry. In comparison, an ultrafine grain has better mechanical properties as a higher yield strength and notch impact strength than materials with a coarse grain. Therefore parts with ultrafine grain can be constructed more light-weighted which lowers the material consumption. The material that is saved through this lowers the energy consumption during the production and regarding moving parts, e.g. in combustion engines while usage, too. With the combination of cross wedge rolling and the improved mechanical properties of parts with ultrafine grain the design of processes and material efficiency can be both improved dramatically. The aim of this research project therefore is to develop a cross wedge rolling process that can be used to adjust an ultrafine gain for forging preforms and can be implemented in industry. The target grain size is the same as those producible with processes that are used only in research projects like ECAE. In the end the mechanical properties of the grain like the average grain diameter should be associated with geometry and process parameters at cross wedge rolling. The first of three sub-aims is to develop a suitable cross wedge rolling process that can successfully form cylindrical parts. The tools should be able to be varied systematically. Within the second sub-aim a dependency of the cross wedge rolling process from process parameters like forming velocity and billet temperature has to be investigated. Within the third sub-aim a dependency from cooling conditions after the cross wedge rolling should be examined. The cooling conditions determine the final grain size based on the nuclei grown at cross wedge rolling. Therefore different cooling velocities and fluid have to be investigated.

通过楔横轧生产的预成型件用于锻造工业的各种部件。它们的特点是剩余材料少。与ECAE相比，楔横轧在工业上已经得到了实施和确立。相比之下，超细晶粒具有比具有粗晶粒的材料更好的机械性能，如更高的屈服强度和缺口冲击强度。因此，具有超细晶粒的部件可以构造得更轻，从而降低材料消耗。通过这种方式节省的材料也降低了生产过程中的能源消耗，以及使用过程中的运动部件，例如内燃机。楔横轧与超细晶粒零件力学性能的提高相结合，可以显著提高工艺设计和材料效率。因此，本研究项目的目的是开发一种楔横轧工艺，可用于调整锻造预成型件的超细增益，并可在工业中实施。目标晶粒尺寸与仅用于ECAE等研究项目的工艺生产的晶粒尺寸相同。最后，晶粒的机械性能（如平均晶粒直径）应与楔横轧的几何参数和工艺参数相关联。三个子目标的第一个是开发一种合适的楔横轧工艺，可以成功地形成圆柱形零件。工具应该能够系统地变化。在第二子目标内，必须研究楔横轧工艺与工艺参数（如成形速度和坯料温度）的依赖性。在第三个子目标内，应检查楔横轧后冷却条件的依赖性。冷却条件根据楔横轧时生长的晶核决定最终的晶粒尺寸。因此，必须研究不同的冷却速度和流体。