Theme I: Interim report of the research group on visualization of melt dripping behavior in the lower region of hydrogen-enriched blast furnaces
Chairperson: K. Ohno (Kyushu Univ.)

This research group aims to systematically understand the behavior of molten materials in the lower region of hydrogen-enriched blast furnaces, with a particular focus on the dripping zone.
In recent hydrogen-enriched operations, changes in reduction behavior and heat flow ratio have been reported, which may alter the shape, position, and thickness of the cohesive zone. These changes are expected to significantly affect melt generation and flow behavior in the dripping zone, as well as the complex gas–solid–liquid interactions in the lower furnace region.
Based on this background, the research group seeks to organize and integrate the phenomena in the dripping zone from the following perspectives:

• Melt generation behavior (onset of dripping and melting processes)
• Carbonaceous material behavior (including the effects of steam gasification history on coke properties)
• Melt flow behavior (dripping, retention, and flow characteristics)
• Advanced understanding through modeling and numerical simulations

Furthermore, by comparing conventional blast furnaces with hydrogen-enriched blast furnaces, the study aims to clarify how structural changes in the furnace and cohesive zone influence the lower furnace behavior, and to establish a common framework within the research community.
In this session, as an interim report of the research group, key controlling factors and remaining challenges related to melt behavior in the lower region will be presented, and future research directions will be discussed.

Theme II: Cokemaking technology for utilization of carbon neutral resources (Final report meeting of the study group of "Cokemaking technology for enhancement toward next generation")
Chairperson: T. Takanohashi (AIST)

In recent years, the development of CO₂ reduction technologies toward achieving carbon neutrality in the steel industry has become a critical global challenge. In Japan, the introduction of innovative ironmaking process technologies based on the blast furnace route, is planned for implementation from the 2030s onward. In blast furnace ironmaking, high-strength coke that can ensure sufficient gas and liquid permeability remains indispensable for maintaining high productivity and stable operation. Furthermore, to achieve CO₂ emission reductions in blast furnace operations, there is a strong demand for technologies to produce coke utilizing carbon-neutral resources such as biomass.
Building on the outcomes of the preceding research group, “Cokemaking Technology for Low CO₂ Emission and High Quality while Extending Available Resources”, this research group has been working to explore and further develop seed technologies that enable a significant expansion in the utilization of carbon-neutral resources, including biomass.
At this discussion session, research outcomes obtained by the research members will be presented and discussed in detail. As this session also serves as the final report meeting of this research group, discussions will additionally focus on future directions for the application of this group’s research outcomes, and active and constructive discussions among all participants are highly anticipated.

Theme III: Development of electric arc furnace and melting furnace technologies to realize carbon neutrality in the Japanese steel industry
Chairperson: N. Ishiwata (JFE)

Nippon Steel, JFE Steel, Kobe Steel, and the Japan Research and Development Center for Metals (JRCM), collaborating with many universities and research institutes, have organized the “Hydrogen Steelmaking Consortium” to realize carbon neutrality in steel production.
Last year, a symposium on the development of hydrogen‑based reduction technologies was held. This year, we will focus on smelting and refining process of direct‑reduced iron and scrap. Compared with the blast furnace route, the melting processes have long been considered challenging for producing high‑grade steel, because the removal or reduction of nitrogen and phosphorus, as well as tramp elements, is difficult. In addition, increasing smelting rates and productivity comparable with BF process is another issue. In this session, we focus on these subjects covering fundamental study, elemental technologies to actual issue of the process, and discuss on not only research activities but also their perspectives on future developments.

Theme IV: The development of emerging and advanced seed technologies through the 'Steel Carbon Neutral Research Grant'
Chairpersons: N. Kikuchi (JFE), T. Hoshino (The Univ. of Tokyo), H. Murakami (Science Tokyo)

ISIJ established the "Steel Carbon Neutral (CN) Study Committee" in fiscal year 2022. This committee serves as a forum to discuss scenarios for achieving carbon neutrality in the steelmaking process without compromising industrial competitiveness, and it continues its activities.
Under the "Steel Carbon Neutral (CN) Study Committee," a new "Steel Carbon Neutral Research Grant" program was established to promote fundamental research and to discover emerging and advanced seed technologies that contribute to carbon neutrality in the steel industry. Now that three years have passed since the grant program began in 2022, we held the first symposium last autumn to provide an opportunity to report on the outcomes achieved so far. The event was well received by many participants. Building on this success, we will hold the 2nd Symposium this year to showcase emerging and advanced seed technologies contributing to carbon neutrality in the steel industry, developed through the research grants.We look forward to your participation.

ThemeV: Interim report session of the research group “Thermal energy storage technologies for carbon neutrality of the Iron & Steel Industry”
Chairperson: T. Nomura (Hokkaido Univ.)

Achieving Carbon Neutrality (CN) is the most urgent and critical challenge facing the modern steel industry.
In 2025, The 7th Strategic Energy Plan of Japan explicitly recognized the importance of "Thermal Energy Storage" (TES) for the first time in history. In this "Year One of Thermal Storage in the 21st Century, Division of Sustainable System established the research group on “Thermal Energy Storage Technologies for Carbon Neutrality of Iron & Steel Industry". Our mission is to promote research on TES as a key technology for CN, enabling optimized energy utilization that transcends temporal, qualitative, and spatial gaps.
Based on the latest advancements in TES research, this group aims to simultaneously address the following three key pillars:

• Thorough Energy Saving: Pursuit of advanced recovery and effective utilization of unused steelmaking waste heat.
• CCU (Carbon dioxide Capture and Utilization) Technologies: Integration of energy saving and CCU through exergy regenerative (thermochemical) technologies.
• Introduction of Variable Renewable Energy (VRE): Development of innovative TES systems as a foundation for the economically rational utilization of VRE power sources.

Beyond mere technical development, we plan to conduct detailed explorations of potential applications and case studies based on prospective life cycle assessment to evaluate the implementation effects from multifaceted perspectives.
This session serves as an interim report meeting for the research group. We aim to share our current findings and engage in deep discussions regarding the feasibility of implementing TES technologies in the steel industry. We look forward to active participation and a vibrant exchange of knowledge from across industry, government, and academia.

ThemeVI: Equipment diagnostics in ironworks using 3D area sensing
Chairpersons: I. Ishii (Hiroshima Univ.), T. Ichikawa (JFE)

To achieve stable operation and reduce human-resources for maintenance and condition monitoring for large-scale infrastructure in ironworks, it is necessary to develop cyber-physical integrated monitoring technology. This technology involves the spatial visualization of structural deterioration through 3D digital reproduction, which integrates the spatial measurement of both vibration and strain distribution over a wide area (3D area sensing) with its simulations. The latest research regarding wide-area cyber-physical monitoring technology will be shared and discussed in this symposium.

ThemeVII: Systemic optimization of exergy flows in steel production processes
Chairperson: H. Suwa (Setsunan Univ.)

Since improving the efficiency of exergy flows (encompassing both material and energy flows) and balancing supply and demand within steel production processes are inherently interactive and synergistic, a systemic approach to problem-solving is essential. This session will discuss the development of exergy flow models for steel production and systemic methodologies for optimizing the balance and efficiency of exergy supply and demand. Furthermore, we will explore the future of production management support technologies to achieve carbon-neutral manufacturing.

ThemeVIII: Recent trends of the analysis of strip rolling processes
Chairperson: J. Yanagimoto (The Univ. of Tokyo)

Analysis of the stress field and deformation of strip under rolling is indispensable to elucidate the characteristics of strip rolling processes. In this round-table talk, researches on recent trends of the analysis of strip rolling processes will be presented and discussed.

ThemeIX: Current status and future perspectives of digital twin technologies for pipe manufacturing
Chairpersons: A. Matsumoto (JFE), M. Mizumura (NIT, Kure College)

Steel pipes are applied in diverse industries, and pipe manufacturing is increasingly required to meet specification requirements for dimensional accuracy and mechanical properties. Accordingly, interest in digital transformation (DX) and digital twin technologies in pipe manufacturing has been increasing. This discussion session reviews the current state of digital twin applications and their potential for future operational decision support.

ThemeX: Science of martensitic microstructures and their role in material property development
Chairperson: S. Morito (Shimane Univ.)

Amid increasing demands for resource and energy savings in transportation systems, the application of high‑strength martensitic steels continues to expand. However, practical issues such as ensuring sufficient formability and preventing hydrogen embrittlement remain significant challenges. Because these mechanical properties are closely linked to the martensitic microstructure, precise microstructural control is essential. This workshop will focus on recent advances in microstructure characterization and modeling techniques, and will discuss the mechanisms of martensite formation as well as the relationships between microstructure and deformation/fracture behavior from multiple perspectives. The goal is to deepen fundamental understanding and generate insights that contribute to improved performance and broader industrial applications of high‑strength steels.