Integrative material and process model for the correlation of phase morphology and flow behavior of spheroidization annealed low-alloyed carbon steels

复相钢材料的强度、韧性和延性等力学性能并不仅仅取决于其化学成分和相成分的体积分数。相反，在半成品制造和热处理过程中使用的组织形态，例如球化退火，具有显著的影响。例如，渗碳体形态对球化退火钢的力学性能的影响已经被各种研究证明。然而，目前的研究状况缺乏对热处理条件与由此产生的钢材料的流动性能和变形行为之间的综合关系的基本了解，这些关系是通过钢材料组织的形态变化来实现的。这个问题的解决方案致力于这个项目，在这个项目中，复杂的相互作用是通过实验确定的，并在此基础上建立一个数值模型。从纯热和外应力辅助热处理、扫描电子显微镜原位金相、二维和三维金相、单相性质的测定以及多轴体积成形等领域的各种实验技术代表了实验方法。数值模型应该包括几个模拟工具，如用于相的时间和空间发展的相场理论、用于确定材料最终性质的代表性体积元素以及用于将所获得的结果传递到其他材料的人工神经网络。为了验证该模型，需要对成形性的实际表征进行实验研究。模拟结果将有助于更好地理解强度特性与变形行为、组织发展和软退火参数之间的关系。与实践相关的优势在于，能够根据各自的下游成形工艺，通过所建立的关系以有针对性的方式反向控制所需的流动特性，以节省不必要的退火时间，并确保钢材的互换性。

The mechanical properties of multiphase steel materials such as strength, toughness and ductility do not depend solely on their chemical composition and the volume fraction of phase constituents. Rather, the microstructure morphology used in the course of semi-finished product manufacture and heat treatment, e.g. of spheroidization annealing, has a pronounced influence. For example, the influence of cementite morphology on the mechanical properties of spheroidizing annealed steels has already been demonstrated by various investigations. However, the current state of research lacks a fundamental understanding of the integrative relationship between heat treatment conditions and the resulting flow properties and deformation behaviour of a steel material via the morphology change of its microstructure. The solution to this problem is devoted to this project, in which the complex interactions are determined experimentally and building on that, a numerical model will be created. Various experimental techniques from the field of purely thermal and external stress assisted heat treatment, SEM-in situ-, -2D- and -3D-metallography, the determination of individual phase properties as well as multiaxial bulk forming represent the experimental approach. The numerical model should comprise several simulative tools such as the phase field theory for temporal and spatial development of phases, representative volume elements for determining the final properties of the material and artificial neural networks for transferring the results obtained to other materials. To validate the model, experimental investigations of the practical characterization of formability are required. The results from modelling should contribute to an improved understanding of the relationships between strength properties and deformation behaviour, microstructure development and soft annealing parameters. A practice-relevant advantage opens up by the possibility of being able to control the required flow properties inversely via the established relationships in a targeted manner in accordance with the respective downstream forming process, to save unnecessary hours of annealing and to ensure the interchangeability of steel materials.