Papers by Author: Kunio Matsuzaki

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Authors: Kanichi Hatsukano, Kunio Matsuzaki
Authors: Kunio Matsuzaki, Yoichi Murakoshi, Toru Shimizu, Kaoru Kikuchi
Abstract: Machined AZ31 alloy chips were consolidated by hot-pressing and then hot-extrusion at 300 °C, and their workability was evaluated. The consolidated sample has a fully dense microstructure with fine equiaxed grains. The compression and backward extrusion tests reveal that the consolidated AZ31 chips have a good workability at above 200°C. It is said that the recycled AZ31 alloy by hot-extrusion of the chips is suitable for forging materials and the process is useful for the recycling of Mg chips.
Authors: Takashi Murakami, Kunio Matsuzaki
Abstract: In this study, the friction and wear properties of the Fe7Mo6-based alloy/Al2O3 tribopair were investigated at high temperatures in air and at 298 K in water. The Fe7Mo6-based alloy/Al2O3 tribopair exhibited friction coefficients as low as 0.5 at 298 K and 873 K in air. On the other hand, this tribopair exhibited higher friction coefficients at 573 K than at 298 K and 873 K. It was also found that the friction coefficients of this tribopair were approximately 0.5 in water. The Fe7Mo6-based alloy disk specimens and their paired Al2O3 ball specimens exhibited the highest specific wear rates at 873 K in air. Oxygen-rich phase was observed on the worn surfaces of all the disk specimens. Concerning the friction and wear tests at high temperatures in air, the amount of the oxygen-rich phase increased with increasing the testing temperature. In addition, a little larger amount of the oxygen-rich phase was observed on the worn surface formed at 298 K in water than that formed at 298 K in air.
Authors: Takashi Murakami, Yuko Hibi, Hiroki Mano, Kunio Matsuzaki, Haruyuki Inui
Abstract: In this study, the friction and wear properties of the siliconized, chromized and borochromized SS 400 steel/Si3N4 tribopairs were investigated in ethyl alcohol at 298 K. The surface of the siliconized plate specimens mainly consisted of Fe3Si, while the surfaces of the chromized and borochromized steel plate specimens were mainly composed of Fe-Cr alloy and Cr2B phases, respectively. The borochromized specimens exhibited the highest microvickers hardness of all the plate specimens. Also, it was found that both the chromized and borochromized steel specimens exhibited friction coefficients as low as 0.2 in ethyl alcohol, and that the friction coefficients of the siliconized steel specimens were slightly lower than those of the non-coated steel specimens.
Authors: Toru Shimizu, Kunio Matsuzaki
Abstract: Already, we are developing the process to produce stainless steel foam over 97% porosity using hydro-gel binder. However, this process is very sensitive process, and foaming condition is affected by the slight deference of heating temperature. Therefore, we tried to improve the process by changing the foaming agent and foaming conditions. By the improvement of the process, the foaming operation becomes stable and finer cell size stainless steel foam can be obtained.
Authors: Kunio Matsuzaki, Kanichi Hatsukano, Kotaro Hanada, T. Shimizu, T. Sano
Authors: Kunio Matsuzaki, Kanichi Hatsukano, Y. Torisaka, Kotaro Hanada, Toru Shimizu, M. Kato
Abstract: Mg-Al-Zn alloys containing 0.5% Ca were strip cast into sheets with a thickness of about 1.0mm by twin roll caster. It is found that the addition of Ca to Mg95Al5-XZnX (wt%)alloys prevents the oxidation and burning of molten, and makes the melting and casting easy. The as-cast Mg96Al4Zn0.5Ca0.5 alloy sheet has few cracks at the edge. With increasing Zn content, the generation of cracks occurs more markedly. The as-cast alloys have equiaxed grains with an average grain size of 10 μm. A fine microstructure is obtained. All the samples consist of single hcp-Mg phase. The yield and ultimate tensile strength of the as-cast sheets are in the range of 180 to 200 MPa and 265 to 275 MPa, respectively. The alloy Mg95Al2Zn2.5Ca0.5 shows an elongation of 21% as well as a high strength of 275 MPa. The annealing at 400 °C causes an improvement of elongation to 24% and 30% for Mg96Al4Zn0.5Ca0.5 and Mg95Al2Zn2.5Ca0.5,respectively. A further enhancement of mechanical properties is expected by an appropriate thermomechanical treatment. The as-cast Mg96Al4Zn0.5Ca0.5 sheet was deep drawn at 250°C and a drawing ratio of 2.0 without cracking . In summery, the Ca added Mg alloys are suitable for the production of Mg alloy sheets by strip casting and the cast alloy sheet have high strength with ductility and good formability
Authors: Toru Shimizu, Kotaro Hanada, Satoru Adachi, Masahito Katoh, Kanichi Hatsukano, Kunio Matsuzaki
Abstract: Stainless steel sludge is generated as a waste in the grinding process, and the possibility of recycling stainless steel is considered here. Generally, stainless steel grinding sludge ranging about 10,000 are generated per a year in Japan, and most of it is discarded or re-melted with scrap steel. In this study, we considered the possibility of using the stainless steel sludge as metal powder for MIM or raw material for metal foam. For the MIM process, the metal powder will need some improvement, and flotation and spheroidizing processes of the sludge are necessary. For fabrication of the metal foam, untreated sludge can be used, and steel foam about 90% porosity is produced.
Authors: Kunio Matsuzaki, Kotaro Hanada, Kanichi Hatsukano, Toru Shimizu
Authors: Kanichi Hatsukano, Kunio Matsuzaki, Toru Shimizu, Kichitaro Shinozaki
Abstract: The Formability of magnesium wrought alloys, AZ61 and AZ31 were investigated . First, the cylinder compression tests were carried out at room temperature and elevated temperatures. Then, the possibility of applying the warm lateral extrusion of the AZ61 and AZ31 alloys were examined under several conditions by using the multi-axes material testing machine. A cylindrical billet coated with molybdenum disulfide lubricant was set in the horizontal die cavity and the billet was heated up to the extrusion temperature, and then extruded laterally under the two horizontally advancing punches. Furthermore, lateral extrusion with counteracting pressure on the end of branches by using two punches methods was tried to reduce the extrusion temperature and sound products was obtained around 190°C.
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