Investigation of the thermomechanical interactions in the shear zone during the fine blanking of heated high strength sheet materials (HotFib)

研究加热高强度板材精冲过程中剪切区的热机械相互作用 (HotFib)

• 批准号: 372316085
• 负责人: Professor Dr.-Ing. Thomas Bergs, since 7/2019
• 金额: --
• 依托单位: Werkzeugmaschinenlabor - WZL
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/372316085?language=en
• 关键词: Investigation; thermomechanical; interactions; shear; zone

The research project is based on the research hypothesis that by means of inductive sheet heating, high-strength materials can be processed reliably, the cutting force can be significantly reduced and the component quality can be improved by fine blanking. Thus, the manufacturing process fine blanking may be capable of the thermo-mechanical mechanisms need to be understood and explained in the shear zone. Heating the sheet metal leads to a lower flow stress, which promotes the plastic material flow and reduces the necessary process forces during fine cutting. By lowering the blanking force, the fine blanking process will be qualified for processing thicker sheets and offers additionally the possibility to process ultra-high sheet metal materials. The interactions between the heating of the sheet material, the blanking force, the achievable component quality as well as the knowledge of the precise thermomechanical mechanisms is unknown for fine blanking. In order to confirm this research hypothesis experimental and numerical investigations will be carried out. By means of the system TTH25 different heating profiles will be applied to sheet metal materials (16MnCr5, 42CrMo4). Furthermore, different inductor designs will be tested in order to analyze the influence of the heat distribution during the fine blanking process. The thermomechanical mechanisms of action are described by analyzing the section quality (microstructure, surface quality) and their correlation with the heating profiles as well as the process characteristics (blanking force, v-ring force, counter force). The numerical FE process simulations support the experimental methods to allow further correlations with the stress-strain state and other difficult to measure quantities (true strain). All partial results (blanking force reduction, section quality, hydrostatic stress state, elongations) are combined with each other to form a holistic explanation model considering the sheet thickness, the sheet metal material and the thermomechanical mechanisms of action. The aim is to extend the calculation of blanking force, v-ring force and counter force for the fine blanking process with a temperature factor. This allows the analytical calculation of the process forces as a function of the temperature. Furthermore, different empirical-analytic function surfaces will be derived that reflect the functional relationship between heating temperature, part quality and part properties considering on the sheet material, the sheet thickness and the hydrostatic stress state. In this way, the postulated research hypothesis is examined and, in conjunction with the validation of the explanation model, the superior research objectives will be achieved.

本研究项目基于以下研究假设：通过感应片材加热，可以可靠地加工高强度材料，显著降低切削力，并通过精冲提高零件质量。因此，精密落料的制造过程中可能需要了解和解释剪切区的热-机械机制。加热金属板材导致较低的流动应力，这促进了塑性材料的流动，并减少了精切过程中必要的工艺力。通过降低落料力，精落料工艺将有资格加工较厚的板材，并提供额外的可能性，以加工超高板材材料。板材的加热，落料力，可实现的部件质量以及精确的热机械机制之间的相互作用是未知的。为了证实这一研究假设，将进行实验和数值研究。通过系统TTH25不同的加热型材将适用于钣金材料（16MnCr5, 42CrMo4）。此外，还将测试不同的电感设计，以分析精冲过程中热量分布的影响。通过分析断面质量（显微组织、表面质量）及其与加热型态的关系，以及工艺特性（落料力、v形环力、反力），阐述了热力学作用机理。数值有限元过程模拟支持实验方法，允许进一步关联的应力-应变状态和其他难以测量的量（真应变）。所有部分结果（落料力减小、断面质量、静水应力状态、伸长率）相互结合，形成考虑板料厚度、板料材料和作用机理的整体解释模型。目的是扩展考虑温度因素的精密冲裁过程的冲裁力、v形环力和反力的计算。这允许分析计算过程力作为温度的函数。在此基础上，在考虑板材材料、板材厚度和静水应力状态的情况下，推导出不同的反映加热温度、零件质量和零件性能之间函数关系的经验解析函数曲面。通过这种方式，检验假设的研究假设，并结合解释模型的验证，实现优越的研究目标。