Determination of forming limits of the martensitic chromium steels in hot forming processes

马氏体铬钢热成形过程成形极限的测定

基本信息

批准号：
385989694
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：
Research Grants (Transfer Project)
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/385989694?language=en
关键词：
Determination forming limits martensitic chromium

项目摘要

The aim of the planned research project is numerical simulation of the hot forming of a martensitic chromium steel taking into account the forming limit at elevated temperatures, the resulting microstructure and their effects on the product properties. In the sheet metal forming, hot forming of martensitic chromium steels has various advantages over hot stamping of manganese-boron steels, such as a lower critical cooling rate, a higher elongation at break (fracture strain) along with higher strengths and a better corrosion resistance of the material. During the hot forming processes, complex interactions between the workpiece temperature, the tool temperature and the process time exist which significantly influence the microstructure, the final component properties and the residual stresses as well as the component distortion thus numerical modelling and prediction of the process limits is of particular importance for this process. In particular, the higher material costs of martensitic chromium steels compared to the manganese-boron steels make a simulative process design vital in order to save resources, tests and thus reduce the costs. The planned development of a material model for the numerical simulation of hot forming of martensitic chromium steels will be carried out based on a material model which was developed in the DFG funded preceding research projects for hot stamping of the manganese-boron steel (22MnB5). A comprehensive material characterization is required in order to adapt the material model to the martensitic chromium steels and their microstructural behavior.For the determination of the forming limits of sheet metals, the use of forming limit diagrams is state of the art. As the flow behavior and the deformability of a material are dependent on the temperature, conventional forming limit diagrams obtained at room temperature cannot be used for hot forming processes. In order to predict the deformability of martensitic chromium steels as well as the influence of the forming temperature on the deformability in the hot forming process, the further objective of this project lies in the determination of temperature-dependent forming limit diagrams and their implementation in the numerical simulation. This allows a realistic evaluation of the forming limit and the resulting component properties after cooling. The numerical model is validated with the help of hot formed demonstrator components.

该计划研究项目的目的是对马氏体铬钢的热成型进行数值模拟，同时考虑高温下的成型极限、产生的微观结构及其对产品性能的影响。在板材成形中，马氏体铬钢的热成形比锰硼钢的热冲压具有多种优势，例如较低的临界冷却速率、较高的断裂伸长率（断裂应变）以及较高的强度和更好的耐腐蚀性的材料。在热成形过程中，工件温度、工具温度和加工时间之间存在复杂的相互作用，这对微观结构、最终部件性能、残余应力以及部件变形产生显着影响，从而对工艺极限进行数值建模和预测对于这个过程尤为重要。特别是，与锰硼钢相比，马氏体铬钢的材料成本较高，因此模拟工艺设计对于节省资源、测试并降低成本至关重要。计划开发用于马氏体铬钢热成型数值模拟的材料模型将基于 DFG 资助的先前锰硼钢 (22MnB5) 热冲压研究项目中开发的材料模型。为了使材料模型适应马氏体铬钢及其微观结构行为，需要进行全面的材料表征。为了确定金属板材的成形极限，成形极限图的使用是最先进的。由于材料的流动行为和变形能力取决于温度，因此在室温下获得的传统成形极限图不能用于热成形工艺。为了预测马氏体铬钢的变形能力以及成形温度对热成形过程中变形能力的影响，该项目的进一步目标在于确定与温度相关的成形极限图及其在热成形过程中的实施。数值模拟。这样可以对成形极限和冷却后所得的部件性能进行实际评估。数值模型在热成型演示组件的帮助下进行了验证。