GOALI/Collaborative Research: Understanding Formation and Removal Mechanisms of Micron-sized Non-metallic Inclusions in Steel Refining by Computational and Experimental Studies

钢是最通用的结构材料之一，在历史和社会进步中发挥了至关重要的作用。随着对钢铁的要求越来越苛刻，炼钢对钢包（用于输送和倒出钢水的容器）的化学、微观结构以及表面和内部质量特性提出了严格的工程要求。在炼钢过程中，钢材清洁度，即非金属夹杂物的数量和大小，是一个关键问题，它直接影响到后续的加工步骤和钢铁产品的质量。微米大小的非金属夹杂物通常使用氩气和/或电磁搅拌去除。这些过程虽然非常困难，但对于最小化轻质高性能组件的此类夹杂物至关重要。由于缺乏对复杂机理的基本认识和量化夹杂物形成和运移的能力，阻碍了钢包精炼过程中夹杂物控制的进展。这是一项由两个机构和两家钢铁公司合作的学术联络机会项目，旨在研究钢包精炼钢液过程中微米级非金属夹杂物的形成和去除。在这个项目中强有力的合作伙伴关系独特地促进了技术转让给钢铁制造商，提高了产品质量和生产力，从而提高了美国钢铁和相关行业的竞争力。该奖项还将为学生提供学术和工业研究的机会，项目成果将在外展活动中展示，以激励K-16学生追求STEM教育和职业。为了解决钢包精炼过程中夹杂物带来的挑战，该项目旨在获得解决以下问题的基础知识：在氩气和/或电磁搅拌过程中产生微米级夹杂物颗粒的机制是什么；渣/钢界面的流动剪切不稳定性是否会产生微米级的夹杂物？渣基夹杂物是否是钢水中非金属夹杂物总浓度的主要来源？该团队将把计算流体动力学（CFD）建模与实验室水建模和微流体实验结合起来，并在钢铁厂进行基础研究的现场测量。预计该项目的成果将提供以下技术见解：(1)钢渣界面流动不稳定性、渣基夹杂物与非金属夹杂物总量之间的关系；(2)搅拌速率对渣夹杂物生成、夹带以及夹杂物浮选的定量影响；(3)验证CFD模型的实验技术与方法；(4)钢包精炼高保真综合三维多相、多尺度、多物理场、多种类CFD模型。可为钢材洁净度控制和高质量批量生产提供最佳实践指导。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Steel is one of the most versatile structural materials and has played a vital role in history and societal advancements. With the increasingly harsh environments demanded of steel, steelmaking requires strict engineering of chemistry, microstructure, and surface and interior quality characteristics of the ladle - the vessel used to transport and pour out molten steel. In steelmaking, steel cleanliness, defined as the amount and size of non-metallic inclusions, is a critical issue and directly influences both subsequent processing steps and the quality of steel products. Micron-sized non-metallic inclusions are typically removed using argon and/or electromagnetic stirring. These processes, though very difficult, are crucial to minimize such inclusions for lightweight high-performance components. The lack of fundamental knowledge of complex mechanisms and the ability to quantify the formation and transport of inclusions has hindered progress in the inclusions control in ladle refining. This Grant Opportunities for Academic Liaison with Industry project, collaboration between two institutions and two steel companies, pursues fundamental research on the formation and removal of micron-sized non-metallic inclusions during liquid steel refining in a ladle. The strong partnership in this project uniquely facilitates the know-how transfer to steel manufacturers with improved product quality and productivity, and therefore, increases the competitiveness of U.S. steel and relevant industries. The award will also provide students with opportunities of academic and industrial research and the project results will be showcased in outreach events to inspire K-16 students to pursue STEM education and careers.To tackle the challenge associated with inclusions in a ladle refining process, this project aims at obtaining basic knowledge that will address such questions as: what are the mechanisms that generate micron-sized inclusion particles during argon and/or electromagnetic stirring; can flow shear instability at the slag/steel interface generate micron-sized inclusions and are slag-based inclusions the primary source to the total concentration of non-metallic inclusions in molten steel? The team will integrate computational fluid dynamics (CFD) modeling with laboratory water modeling and microfluidic experiments as well as on-site measurements in steel plants for fundamental studies. The outcomes of the project are expected to provide the following technical insights: (1) the relationships between flow instability at the steel-slag interface, slag-based inclusions, and the total amount of non-metallic inclusions, (2) the quantitative effects of stirring rate on the slag inclusion generation and entrainment, as well as inclusion flotation, (3) experimental technique and methodology for validating the CFD model, and (4) a high-fidelity comprehensive three-dimensional multiphase multi-scale, multi-physics, and multi-species CFD model for steel ladle refining, which can be employed to provide best practice guidance for steel cleanliness control and high-quality mass production.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.