Theme I: Latest researches for clarification of the evolution mechanism of inclusions during steel solidification process
Chairpersons: H.Matsuura (The Univ. of Tokyo) ,T.Hirosumi (Nippon Steel)
Non-metallic inclusions in steel greatly affect various physical properties of steel, such as mechanical properties and corrosion resistance. Therefore, various studies have been conducted to establish methods for reducing and modifying inclusions. In this discussion session, the latest research from fundamental to applied fields will be shared a wide range of scientific theories and technologies will be discussed to deepen our understanding of various phenomena such as formation, growth, and change of inclusions during the solidification process involving drastic changes in a series of steel manufacturing processes from refining to processing and to actively control such phenomena.

Theme II: Stabilization technology for manufacturing and strip threading in a continuous process (Warped, bended, meandered, and shaped)
Chairpersons: Y.Nakamura (Nippon Steel) , Y.Matsubara (JFE Steel)
The demands of metal quality and stability of manufacturing/threading are increasing in conjunction with the increasing requirements of stricter metal quality, higher tensile strength and thinner gauge. In this session, some technological developments will be introduced from the point of view, process problems for threading stability, such as warp, bending, meandering, shape defect and strip breaking, which have been increasingly stricter with the demands of higher quality. We hope that discussion will be held to explore future trends in stabilization technology.

Theme III: Needs for tubes with uneven thickness and their manufacturing and forming techniques 4
Chairpersons: T.Kuwabara (Tokyo Univ. of Agriculture and Technology), T.Furushima (The Univ. Tokyo)
There is a demand in the industry for steel tubes with uneven thickness, in which excess tube thickness is reduced as with tailored sheet blanks, to further reduce the weight of transportation equipment such as automobiles. Uneven thickness tubes have locally thickened sections at which the thickness is to be reduced in the second forming process. Another example of uneven thickness tube is that having the thickened ends for pre-reinforced tube joints. In addition, these uneven thickness tubes are highly applicable to non-transport equipment. This session aims to discuss the needs of tubes with uneven thickness and their manufacturing and forming technologies.

Theme IV: Investigation of bio-corrosion of structural materials -diagnosis and analysis-III
Chairperson: Y.Miyano(Akita Univ.)
Proposal of new experimental method on visualization of biofilm formation and corrosion progress of metal surface, accumulation of new findings concerning microorganisms and their metabolite involved in bio-corrosion, and elucidation of bio-corrosion mechanism or development of counter measures / mitigation technology for bio-corrosion are considered to be the themes that contain important research topic of material science. In this discussion session, researches from various field such as materials science, microbiology, and environmental chemistry will be presented and discussed.