Masaaki Fujioka

TL;DR: In this article, the role of Mn depletion at the interface of MnS and ferrite matrix was investigated to elucidate the mechanism of intra-granular ferrite transformation in the Heat Affected Zone (HAZ) of welded joints.

TL;DR: In this paper, a mathematical model for the prediction of the microstructural evolution and the mechanical properties of the steel plates produced by TMCP enables this integrated control, which consists of four modules such as heating, rolling, cooling, and mechanical properties in which the metallurgical phenomena occurring at each step are calculated.

TL;DR: In this article, a steel plate having high toughness, low yield ratio and high fatigue strength is provided by preserving the fine metallographical microstructure of martensite or bainite.

TL;DR: In this article, the authors show that the use of heavy deformation with strain over 0.7 per pass has been employed as a key technique to reach the goal, and has been revealed in laboratory scale studies: (a) to enhance diffusional γ→α transformation and α-recrystallization at a temperature range much lower than the case for the conventional TMCP; (b) to induce a large temperature increase accompanying adiabatic deformation heating which would result in spontaneous reverse transformation when applied in α-region.

TL;DR: In this paper, the authors investigated the fatigue strength of two ultra-fine grained steels (grain sizes 0.8 and 1.μm) and found that an important improvement on smooth fatigue strength was observed.