Development of an efficient evaluation concept for the validation of cryotreatment of tool steels based on instrumented cyclic indentation tests

基于仪器化循环压痕试验，开发用于验证工具钢低温处理的有效评估概念

• 批准号: 521294773
• 负责人: Professor Dr.-Ing. Tilmann Beck
• 金额: --
• 依托单位: Fraunhofer-Institut für Werkzeugmaschinen und Umformtechnik (IWU)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/521294773?language=en
• 关键词: Development; efficient; evaluation; concept; validation

To improve the mechanical properties of tool steels and thus, the lifetime of tools, a cryogenic treatment can be used, which contains an austenitizing and quenching, a cryogenic cooling process at temperatures down to -180 °C as well as a tempering. However, to optimize the process parameters with respect to the material used as well as the application considered, a high effort is required, as the influence of the cryogenic treatment can only be rated within the application. As an alternative, the mechanical properties of the cryogenically treated steel can be thoroughly characterized, which however, requires a high experimental effort. Consequently, the evaluation of a change of the process parameters is very time consuming. The objective of this research work is the development of a concept for an efficient rating of the properties of cryogenically treated tools using the short-time procedure PhyBaLCHT, which is based on instrumented cyclic indentation tests (CIT). As shown in preliminary work, the material parameters determined by this method are useful for rating the mechanical proper-ties of cryogenically treated tool steels. To obtain a sufficient data base, CIT will be performed at differently cryogenically treated specimens made of the tool steel Vanadis 4E, whereby different process sequences and tempering temperatures will be considered. In addition to that, a special focus will be put on the influence of a cyclic cryogenic process on the mechanical properties, in relation to the effects achieved by a single step cryogenic process or a conventional quenching and tempering. Based on these investigations, the lifetime as well as the damage mechanisms of different variants of cryogenically treated Vanadis 4E with sufficiently different properties will be analyzed in fatigue tests as well as conventional and adiabatic blanking tests, whereby the different loading conditions applied will be considered. These results will be correlated to the material parameters determined by PhyBaLCHT, which enables the elaboration of the rating concept and thus, reaching the main objective of this project. To ensure the transferability of this concept to other materials and tools, the microstructures in the initial states as well as their evolution during the cryogenic treatment will be characterized thoroughly. Moreover, this will be complemented by analyses of the microstructural changes caused by the different loadings applied in the fatigue and blanking tests. This concept aims at an efficient rating of the influence of a cryogenic treatment on the mechanical properties of tools and hence, a significant acceleration of the development of cryogenic treatments. Consequently, the objective of this research project is of great scientific and industrial interest for the field of cryogenic treatments of tool steels.

为了提高工具钢的机械性能，从而提高工具的使用寿命，可以使用深冷处理，包括淬火和淬火，在-180 °C以下的低温冷却过程以及回火。然而，为了针对所使用的材料以及所考虑的应用优化工艺参数，需要付出很大的努力，因为低温处理的影响只能在应用范围内评定。作为替代方案，可以彻底表征低温处理钢的机械性能，然而，这需要大量的实验工作。因此，评估工艺参数的变化非常耗时。这项研究工作的目的是开发一个概念，用于低温处理的工具，使用短时间的程序PhyBaLCHT，这是基于仪器循环压痕试验（CIT）的性能的有效评级。初步工作表明，用这种方法确定的材料参数对评定低温处理工具钢的力学性能是有用的。为了获得足够的数据库，将在由工具钢Vanadis 4 E制成的不同低温处理的试样上进行CIT，从而考虑不同的工艺顺序和回火温度。除此之外，将特别关注循环低温工艺对机械性能的影响，与单步低温工艺或常规淬火和回火所实现的效果有关。基于这些研究，将在疲劳试验以及常规和绝热冲裁试验中分析具有足够不同性能的低温处理的Vanadis 4 E的不同变体的寿命和损伤机制，从而考虑所应用的不同加载条件。这些结果将与PhyBaLCHT确定的材料参数相关联，从而能够详细阐述评级概念，从而实现本项目的主要目标。为了确保这一概念可移植到其他材料和工具，将彻底表征初始状态的微观结构及其在低温处理期间的演变。此外，这将通过分析疲劳和冲裁试验中施加的不同载荷引起的微观结构变化来补充。这一概念旨在有效评估低温处理对工具机械性能的影响，从而显著加速低温处理的发展。因此，本研究项目的目标是在工具钢的深冷处理领域具有重大的科学和工业意义。