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

钢是用途最广泛的结构材料之一，在历史和社会进步中发挥了至关重要的作用。随着对钢铁环境的要求越来越苛刻，炼钢需要对钢包（用于运输和倾倒钢水的容器）的化学、微观结构以及表面和内部质量特性进行严格的工程设计。 在炼钢过程中，钢的洁净度（定义为非金属夹杂物的数量和尺寸）是一个关键问题，直接影响后续加工步骤和钢产品的质量。典型地使用氩气和/或电磁搅拌来去除大尺寸的非金属夹杂物。 这些工艺虽然非常困难，但对于最大限度地减少轻质高性能部件的此类夹杂物至关重要。由于对夹杂物形成和迁移的复杂机理缺乏基本认识，以及对夹杂物形成和迁移的量化能力的缺乏，阻碍了钢包精炼夹杂物控制的进展。该项目是两个机构和两家钢铁公司之间的合作，致力于对钢包中钢水精炼过程中微米级非金属夹杂物的形成和去除进行基础研究。该项目中强大的合作伙伴关系独特地促进了向钢铁制造商转让技术，提高了产品质量和生产率，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。为了应对钢包精炼过程中夹杂物的挑战，该项目旨在获得基础知识，以解决以下问题：在氩气和/或电磁搅拌过程中产生微米级夹杂物颗粒的机理是什么;在渣/钢界面处的流动剪切不稳定性可产生微米级夹杂物，并且是渣基夹杂物的主要来源，钢水中的金属夹杂物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以及钢铁厂的现场测量相结合，以进行基础研究。预计该项目的成果将提供以下技术见解：（1）钢渣界面处的流动不稳定性、渣基夹杂物和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和夹带以及夹杂物浮选的定量影响，（3）用于验证CFD模型的实验技术和方法，以及（4）用于钢包精炼的高保真综合三维多相多尺度、多物理场和多物种CFD模型，可用于为钢材清洁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NSF的法定使命，并通过使用基金会的智力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.