2017 Sawamura Award and Guimarães Award (27/09/2017)

Following four papers are awarded the 2017 Sawamura Award and Guimarães Award. [Sawamura Award] ・ Hydrogen Permeation into a Carbon Steel Sheet Observed by a Micro-capillary Combined with a Devanathan-Stachurski Cell【The reason for an award】 ISIJ International, Vol.56(2016), No.3, pp.431-435 Koji FUSHIMI, Misako JIN, Yuichi KITAGAWA, Takayuki NAKANISHI, Yasuchika HASEGAWA(Hokkaido University)  Recently, from the viewpoint of measures against global warming, attention has focused on clean hydrogen energy and high-strength steels that contribute to weight reduction of automobiles. For the design of steel with high hydrogen brittleness resistance, more fundamental study of the mechanism of hydrogen permeation is important.  An electrochemical method for quantitative measurement of the amount of hydrogen entering and permeating into materials has been established by Devanathan et al., and many studies have been done. However, in order to clarify the influence of the crystal structure of the material, it was necessary to elucidate the hydrogen permeation behaviors in more local regions.  The authors made it possible to study hydrogen permeation behavior in areas of the crystal grain size level by incorporating the Devanathan-Stachurski cell in a micro-capillary cell, which has been used to elucidate corrosion behavior. Furthermore, measurement points are specified by using EBSD in combination with this technique. This approach revealed that the diffusion coefficient of hydrogen in carbon steel is at least two times higher at the grain boundary than in single grains.  The point of view of this research is excellent, and the fact that this research addresses important themes in future steel material development, in both the practical and academic fields, is highly appreciated. Moreover, as the paper also notes that additional research will be carried out by this technique, further results are expected in the future. Based on these facts, we consider this paper to be worthy of the Sawamura Award. ・ Development of Biaxial Tensile Test System for In-situ Scanning Electron Microscope and Electron Backscatter Diffraction Analysis【The reason for an award】 ISIJ International, Vol.56(2016), No.4, pp.669-677 Masahiro Kubo,  Hiroshi Yoshida,  Akihiro Uenishi(Nippon Steel & Sumitomo Metal Corporation),  Seiichi Suzuki(TSL Solutions Ltd.),  Yoshiaki Nakazawa(Nippon Steel & Sumitomo Metal Corporation),  Takayuki Hama,  Hirohiko Takuda(Kyoto University)  For the further improvement of the press formability of steel sheets, it is important to clarify the relationship between macroscopic mechanical properties and microstructure under multi-axial deformation state.  In the present paper, the authors developed the experimental system of in-situ observation and analysis for biaxial tensile deformation using electron back scatter diffraction patterns (EBSD) with scanning electron microscope (SEM). Furthermore, the appropriate shape of cruciform specimen for the system was determined by using finite element analysis.  In-situ observation of microstructure during equibiaxial tensile deformation was then conducted using the developed system and the proposed cruciform specimen. The material used was an interstitial-free (IF) steel. It was validated by the comparison with the results obtained by the conventional equibiaxial deformation tests that the developed system successfully realized the equibiaxial tensile deformation.  By the developed method, it becomes possible to directly observe the hardening behavior under biaxial tensile deformation of the thin sheet, and the influence of microstructural change on the change of surface asperity. As a result, further elucidation of the influence of microstructure on macroscopic plastic deformation behavior of various metal materials will be expected.  From the above, the academic and engineering contributions of the present paper are indeed outstanding and worthy of the Sawamura Award. ・ Dynamic Changes in Interfacial Tension between Liquid Fe Alloy and Molten Slag Induced by Chemical Reactions【The reason for an award】 ISIJ International, Vol.56(2016), No.6, pp.944-952 Toshihiro Tanaka,  Hiroki Goto,  Masashi Nakamoto,  Masanori Suzuki(Osaka University),  Masahito Hanao,  Masafumi Zeze,  Hideaki Yamamura(Nippon Steel & Sumitomo Metal Corporation),  Takeshi Yoshikawa(The University of Tokyo)  Interfacial tension between liquid Fe alloy and molten slag is key issue in steel industry. Change in the interfacial tension influences efficiency of steel refining process and cleanliness of steels. It has been reported the interfacial tension between the molten steel and the molten slag decreases when the chemical reaction at the interface occurs. Mechanism of this phenomenon has not been well explained.  In this paper, a novel method to measure the interfacial tension during chemical reactions at high temperatures has been developed. Effect of aluminum addition to the molten steel and viscosity of the molten slag on the change in the interfacial tension has been well investigated. Based on these results, it has been explained that the behavior of the change in the interfacial tension is due to the adsorption of oxygen at the oxygen and the diffusion of oxygen or oxide from the interface into the molten iron alloy and the molten slag.  The study is a useful and detailed, which can help us better understand the slag behavior on slag/steel interface and deserves the Sawamura Award. ・ Effect of Iron Ore Reduction on Ferro-coke Strength with Hypercoal Addition【The reason for an award】 ISIJ International, Vol.56(2016), No.12, pp.2132-2139 Ataru Uchida, Yoshiaki Yamazaki, Shohei Matsuo, Yasuhiro Saito, Yohsuke Matsushita, Hideyuki Aoki(Tohoku University), Maki Hamaguchi(Kobe Steel Ltd.)  High reactivity of BF burden is one of most important factors for high effective BF operation. And coke and iron oxide composite has high reactivity. Then research of producing ferro-coke, which is product from coal and iron oxide heated in coke oven, is promoted.  This paper has high originality, because X-ray micro focus CT and FEM analysis was strictly and novelty applied in the view point of interaction of HPC(Hypercoal) with iron oxide, for increasing coke strength. Concretely, based on three dimensional structural analyses by X-ray micro focus analysis, micro stress distribution was calculated, furthermore coke strength was evaluated on considerable parameters quantitively. In this evaluation, It has a novelty that pore wall thickness was determined by matrix and pore distribution.  As the results, it has been cleared that a large difference with and without the addition of HPC does not appear in the pores surrounding the iron particles generated by the reduction reaction of iron oxide during cooking. And based on the phenomenon, it is necessary to enhance the adhesiveness of coal particles at the thermoplastic temperature for strong coke production and it is effective for increasing strength to add HPC .  The paper apparently has an absolute value with an academic and a technical significance, and thus it is worth will the Sawamura Award. [Guimarães Award] ・ Effect of Si Addition on Oxidation Behavior of Nb containing Ferritic Stainless Steel【The reason for an award】 Tetsu-to-Hagané, Vol.102(2016), No.12, pp.704-713 Yoshiharu Inoue(Nippon Steel & Sumitomo Metal Corporation), Nobuhiko Hiraide(Nippon Steel & Sumikin Stainless Steel Corporation) and Kosaku Ushioda(Nippon Steel & Sumitomo Metal Corporation)  This paper investigates the effect of Si on the oxidation resistance of high purity Nb containing 19% Cr ferritic stainless steels. Main results are that about 0.1% Si addition improves the limit of the oxidation resistance more than 100 K and that the amorphous SiO2 layer acts as an oxidation resistance barrier. These results are helpful for the understanding and the systematization of oxidation resistance of the ferritic stainless steels.  From the above reasons, this paper is worth appreciating from the scientific and technical points and is appropriate for Guimaraes award.