Selective thermally oxidized tool surfaces for dry deep drawing

用于干式拉深的选择性热氧化工具表面

• 批准号: 244930530
• 负责人: Professor Dr.-Ing. Bernd-Arno Behrens
• 金额: --
• 依托单位: Institut für Umformtechnik und Umformmaschinen (IFUM)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/244930530?language=en
• 关键词: Selective; thermally; oxidized; tool; surfaces

Friction and wear have significant influence on tool life in sheet metal forming. Thus lubrificants are generally used to extend the tool life. Since the use of harmful lubricants does not correspond with the target of sustainable production, methods for dry forming are investigated.Within the scope of this project, the production and the use of tool coatings, which are produced by selective thermal oxidation, are investigated. The oxidative heat treatments of the tool surfaces need to take place at a defined oxygen partial pressure. Therefore the treatments are carried out under a protective gas atmosphere (nitrogen) and monosilane doped nitrogen, respectively. With this approach, it is possible to generate oxide coatings with a defined chemical composition and thickness.The results from the first project period show that oxide layers produced under well-defined process conditions feature friction coefficients, which are similar to those measured on the tool surfaces after applying lubricants.In the second phase of this subproject, an innovative heat treatment method has been developed. Initially, a continuous heating process was used to create the oxide layers. This method, however, requires an extensive processing time and an increased amount of process gases. In comparison, the new heat treatment method employs a tube furnace, which allows for the production of oxidecoated specimens with reduced protective gas consumption. In addition, an inductive heating unit was installed in the heating system to decrease process time. Moreover, various surface modifications were investigated in the second phase of the project including friction and wear experiments. Further analysis is needed to understand the behaviour of these coatings under dry metal forming conditions, and thus to ensure transferability to industrial application in the long-term. This aspect, will be one of the key aspects of the research project in its third phase. Specifically, a modular deep-drawing tool equipped with oxidised mold inserts will be developed. By manufacturing different components with various geometries using this tool system it is possible to increase the load collective on the generated oxide layers successively and thus investigate the behaviour of the layer system in a conventional deep-drawing process.At the same time, the heat treatment process to tailor the oxide layers will be adapted with respect the application. Furthermore, the developed numerical model, which was validated on test specimens, will be applied to the geometries investigated in this phase as well. Finally, the rejuvenation process of the layer system will be investigated, to provide for a validated tool life prediction.

摩擦和磨损对金属板材成形中的刀具寿命有显着影响。因此，通常使用润滑剂来延长工具寿命。由于有害润滑剂的使用不符合可持续生产的目标，因此对干成型方法进行了研究。在该项目范围内，对通过选择性热氧化产生的工具涂层的生产和使用进行了研究。工具表面的氧化热处理需要在规定的氧分压下进行。因此，处理分别在保护气氛（氮气）和甲硅烷掺杂的氮气下进行。通过这种方法，可以生成具有确定化学成分和厚度的氧化物涂层。第一个项目阶段的结果表明，在明确的工艺条件下产生的氧化物层具有摩擦系数，与涂抹润滑剂后在工具表面上测量的摩擦系数相似。在该子项目的第二阶段，开发了一种创新的热处理方法。最初，采用连续加热工艺来形成氧化层。然而，该方法需要较长的处理时间和增加的处理气体量。相比之下，新的热处理方法采用管式炉，可以在减少保护气体消耗的情况下生产氧化物涂层样品。此外，加热系统中还安装了感应加热装置，以减少加工时间。此外，在项目的第二阶段还研究了各种表面改性，包括摩擦和磨损实验。需要进一步分析以了解这些涂层在干金属成型条件下的行为，从而确保长期工业应用的可转移性。这方面，将是该项目第三阶段的重点研究内容之一。具体来说，将开发一种配备氧化模具镶件的模块化拉深工具。通过使用该工具系统制造具有各种几何形状的不同部件，可以连续增加所生成的氧化层上的总载荷，从而研究层系统在传统深拉工艺中的行为。同时，定制氧化层的热处理工艺将根据应用进行调整。此外，开发的数值模型已在测试样本上得到验证，也将应用于此阶段研究的几何形状。最后，将研究层系统的再生过程，以提供经过验证的刀具寿命预测。