Motomichi Yamamoto | Hiroshima University (original) (raw)
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Papers by Motomichi Yamamoto
Proceedings of Annual Conference of Japanese Society for Engineering Education, 2007
Journal of High Pressure Institute of Japan, 2019
This paper presents a novel approach of welding thick steel plates that offers time and energy sa... more This paper presents a novel approach of welding thick steel plates that offers time and energy savings compared with conventional techniques. The combination of gas metal arc welding (GMAW) and hot-wire technology simplifies the joint configuration and enhances the process tolerance. In this study, a square butt joint was prepared with as-cut edges and a thickness of 15 mm. The relationship between the welding current and the deposition rate of solo GMAW showed limitations and low process tolerance. Increasing the welding current led to a larger deposited volume with unnecessary weld penetration. An independent deposition volume due to hot-wire insertion was used to improve process tolerance. This approach provided an additional volume without increasing the welding current and reduced unnecessary penetration. With optimized parameters, full-penetration single-pass welding was achieved. Compared with the formation of a typical single-v butt joint at a similar welding speed of 30 cm/...
Welding in the World, 2022
This study investigates high-efficiency and high-quality additive manufacturing (AM) technology u... more This study investigates high-efficiency and high-quality additive manufacturing (AM) technology using a combination of a high-power diode laser and hot-wire method and three kinds of filler wires: stainless steel, Ni-based alloy, and 5000-series Al alloy. The hot-wire method has a high degree of freedom for selecting wire materials because the wire can be heated to just below its melting point by only Joule heating, independent of the main heat source of a high-power diode laser. A simple calculation method to predict the appropriate wire current is proposed and confirmed by hot-wire feeding experiments without laser irradiation. The optimized AM conditions for the three materials were obtained using the appropriate wire current calculated by the proposed method, and three-layer deposited samples were fabricated and evaluated. High-speed imaging was performed to monitor the clear wire melting phenomena and molten pool formation during AM processing.
Proceedings of Annual Conference of Japanese Society for Engineering Education, 2007
Journal of High Pressure Institute of Japan, 2019
This paper presents a novel approach of welding thick steel plates that offers time and energy sa... more This paper presents a novel approach of welding thick steel plates that offers time and energy savings compared with conventional techniques. The combination of gas metal arc welding (GMAW) and hot-wire technology simplifies the joint configuration and enhances the process tolerance. In this study, a square butt joint was prepared with as-cut edges and a thickness of 15 mm. The relationship between the welding current and the deposition rate of solo GMAW showed limitations and low process tolerance. Increasing the welding current led to a larger deposited volume with unnecessary weld penetration. An independent deposition volume due to hot-wire insertion was used to improve process tolerance. This approach provided an additional volume without increasing the welding current and reduced unnecessary penetration. With optimized parameters, full-penetration single-pass welding was achieved. Compared with the formation of a typical single-v butt joint at a similar welding speed of 30 cm/...
Welding in the World, 2022
This study investigates high-efficiency and high-quality additive manufacturing (AM) technology u... more This study investigates high-efficiency and high-quality additive manufacturing (AM) technology using a combination of a high-power diode laser and hot-wire method and three kinds of filler wires: stainless steel, Ni-based alloy, and 5000-series Al alloy. The hot-wire method has a high degree of freedom for selecting wire materials because the wire can be heated to just below its melting point by only Joule heating, independent of the main heat source of a high-power diode laser. A simple calculation method to predict the appropriate wire current is proposed and confirmed by hot-wire feeding experiments without laser irradiation. The optimized AM conditions for the three materials were obtained using the appropriate wire current calculated by the proposed method, and three-layer deposited samples were fabricated and evaluated. High-speed imaging was performed to monitor the clear wire melting phenomena and molten pool formation during AM processing.