研究等業績 - 原著論文 - 宮野 泰征
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溶接部を有するステンレス鋼における微生物腐食初期挙動の統合的理解：金属組織・電位・微生物群集の構造と機能の相互作用の解明
宮野 泰征, 若井 暁, 砂場 敏行, 水上 裕貴, 鴇田 駿, 尾花 望, 野村 暢彦
鉄と鋼 ( 一般社団法人 日本鉄鋼協会 ) advpub ( 0 ) 2025年12月 [査読有り]
研究論文（学術雑誌） 国内共著
<p>Microbiologically influenced corrosion (MIC) is increasingly recognized as a key factor affecting the reliability of welded stainless steel structures. Recent studies highlight early-stage MIC under service-like conditions, emphasizing electrochemical–microbial interactions.</p><p>Laboratory tests using natural freshwater from industrial facilities have revealed corrosion risks in sensitized austenitic stainless steels such as SUS304. In these materials, the open circuit potential (OCP) often shows time-dependent ennoblement that begins earlier and reaches higher values than in non-sensitized base metal. This behavior is linked to microstructural degradation, notably chromium depletion at grain boundaries, and may contribute to the higher MIC susceptibility of sensitized regions.</p><p>Long-term exposure studies across stainless steel grades demonstrate that corrosion morphology－ranging from general to localized or negligible－varies with chromium content and correlates with distinct microbial communities. These findings suggest that microbial populations adaptively localize in response to electrochemical heterogeneity, promoting corrosion initiation and progression.</p><p>To probe this effect, weld-like model systems simulating the interface structure between sensitized and non-sensitized stainless steel regions were tested in a three-electrode setup under controlled micro-scale potential gradients. Electrochemical measurements combined with microbial community profiling indicated functional differentiation between anodic and cathodic areas, with certain taxa preferentially colonizing cathodic sites, suggesting the functional localization of microbial activity driven by electrochemical heterogeneity.</p><p>Overall, these studies highlight the complex interactions among microstructure, electrochemistry, and microbial distribution in MIC initiation. Such integrated insights provide a basis for improved diagnosis and mitigation strategies of MIC in welded stainless steel structures under realistic environmental conditions.</p>
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農業用水施設におけるSUS304サイホン管の局部腐食早期発生事例と要因解析 ─ 現場調査記録に基づく工学的再整理 ─
宮野 泰征, 村井 信昭
鉄と鋼 ( 一般社団法人 日本鉄鋼協会 ) advpub ( 0 ) 2025年10月 [査読有り]
研究論文（学術雑誌） 国内共著
<p>This technical report presents an engineering analysis of an early case of localized corrosion in SUS304 stainless steel siphon pipes used in an agricultural water facility in Akita Prefecture, Japan. Within only a few years after installation, significant wall thinning and perforation were observed, particularly around welded regions, even though stainless steels are generally expected to provide high resistance under neutral freshwater conditions. Radiographic testing (RT) confirmed corrosion shadows and uneven thinning, and the estimated corrosion rate was several times higher than typical values reported for stainless steels in similar environments. Detailed evaluation based on inspection records, design specifications, and operating history suggests that multiple factors overlapped to accelerate the damage. Multiple overlapping factors are considered responsible, including weld-zone sensitization and stagnant/empty-pipe oxygen limitation with possible local chloride build-up. In this context, MIC is treated as a plausible, yet unproven, contributory factor. In this context, microbiologically influenced corrosion (MIC) is treated as a plausible, yet unproven, contributory factor rather than a sole cause. This case highlights that even highly corrosion-resistant alloys may fail to deliver expected performance if site-specific conditions are overlooked. The findings provide important lessons for material selection, corrosion protection, and maintenance strategies in irrigation facilities where stainless steels are widely adopted with expectations of long-term durability.</p>
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Friction Stir Welding of 1.4 GPa-Grade Tempered Martensitic Steel
Miyano Yasuyuki, Washiya Hiroki, Sato Hiromu, Aoki Yasuhiro, Kimura Mitsuhiko, Ushioda Kohsaku, Fujii Hidetoshi
ISIJ International ( 一般社団法人 日本鉄鋼協会 ) 64 ( 12 ) 1795 - 1803 2024年10月 [査読有り]
研究論文（学術雑誌） 国内共著
<p>Thermal hysteresis in fusion welding causes significant weld deterioration in medium- and high-carbon steels. Therefore, the development of an effective alternative welding process is required. Friction stir welding (FSW) is a solid-state welding process performed in an atmosphere that reduces the risks associated with melting and solidification of metals, making it an effective alternative method. Furthermore, it facilitates a flexible in-process control of heat input, which can be achieved by controlling the welding parameters. Considering these, the authors conducted a series of studies to elucidate the characteristics of FSW for medium- and high-carbon steels, including high-strength tempered steels.</p><p>This paper presents the results of applying FSW to 1.4 GPa-grade tempered JIS-S55C steel plates. Five distinct weld types were created by varying the welding parameters, including tool rotation and welding speed. The temperature of the interface between the tool and in-process material was measured using a thermal imaging camera. The microstructure of the welds was evaluated using optical microscopy and field-emission scanning electron microscopy (FE-SEM) with an electron-backscatter diffraction (EBSD) measurement system. The mechanical properties of the welds were evaluated through Vickers hardness and tensile tests. Digital image correlation analysis was employed to analyze the local deformation during the tensile test.</p>
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Comparative Analysis of Aerobic vs. Anaerobic Environments on Microbiologically Influenced Corrosion in Industrial Water
Satoshi Wakai, Hirotaka Mizukami, Toshiyuki Sunaba, Yasuyuki Miyano
Corrosion 2026年01月 [査読有り]
研究論文（学術雑誌） 国内共著
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Corrosion Behavior and Action on Microbes of Copper in a Freshwater Microbiologically Influenced Corrosion Risk Environment
Yasuyuki Miyano, Satoshi Wakai, Kazuhiko Miyanaga, Toshiyuki Sunaba, Hirotaka Mizukami, Nanami Eno
Materials Transactions ( 日本金属学会 ) 64 ( 1 ) 280 - 286 2023年01月
研究論文（学術雑誌） 国内共著
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Dynamics of microbial communities on the corrosion behavior of steel in freshwater environment
Wakai Satoshi, Eno Nanami, Miyanaga Kazuhiko, Mizukami Hirotaka, Sunaba Toshiyuki, Miyano Yasuyuki
npj Materials Degradation 6 ( 41 ) 2022年05月 [査読有り]
研究論文（学術雑誌） 国内共著
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Microbiologically influenced corrosion of stainless steel independent of sulfate-reducing bacteria
Wakai Satoshi, Eno Nanami, Mizukami Hirotaka, Sunaba Toshiyuki, Miyanaga Kazuhiko, Miyano Yasuyuki
Frontiers in Microbiology 13 ( 12 ) 2022年10月 [査読有り]
研究論文（学術雑誌） 国内共著
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淡水環境における腐食時の微生物活動の機能的洞察：バイオインフォマティックアプローチ
若井 暁, 水上 裕貴, 砂場 敏行, 宮野 泰征
鉄と鋼 ( 一般社団法人 日本鉄鋼協会 ) advpub ( 0 ) 2026年02月 [査読有り]
研究論文（学術雑誌） 国内共著
<p>Microbiologically influenced corrosion is known to occur on various materials under diverse environmental conditions. However, information on microbial activity during progression of corrosion in actual environments remains limited. Taxonomic insights into microbial community structures, derived from recent advances in molecular biology techniques, alone are insufficient to understand microbial activity in the corrosion processes. In this study, we aimed to estimate microbial activity during corrosion processes by applying bioinformatic analysis to temporal shifts in microbial community structures observed under actual corrosion conditions. We analyzed the microbial communities present in the corrosion products on various steel materials and in biofilms on non-corroded materials from a freshwater industrial water environment. Abundances of functional genes were estimated from these communities and compared with those estimated from the surrounding water samples. Focusing on energy conversion-related sulfur and nitrogen metabolism, we found substantial shifts in inorganic metabolic gene abundance during the corrosion and biofilm formation processes. Notably, there have been no previous reports addressing metabolic transitions between early and late stages of corrosion. Our findings revealed a notable increase in genes associated with nitrogen fixation and ammonia production during the late corrosion stage, providing crucial insight into nitrogen sources supporting microbial proliferation within corrosion products.</p>
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引張強度1.4 GPa級焼戻しマルテンサイト鋼の摩擦攪拌接合
宮野泰征、鷲谷洋希、佐藤啓陸、青木祥宏、木村光彦、潮田浩作、藤井英俊
鉄と鋼 108 ( 12 ) 945 - 957 2022年12月 [査読有り]
研究論文（学術雑誌） 国内共著
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Scratching of Diamond Substrate Using Fixed Ultra-Hard Abrasive Grain Tool
MIZUMA Hiroyuki, NAKATSU Masanobu, MIYOTA Tatsuya, NAGAO Kota, NAMIKI Ryota, MIZUNUMA Seiji, TAKAHASHI Mamoru, MIYANO Yasuyuki, ITO Shinichi, MURATA Kenji, KAMIYA Osamu
Ｉｎｔｅｒｎａｔｉｏｎａｌ Ｊｏｕｒｎａｌ ｏｆ ｔｈｅ Ｓｏｃｉｅｔｙ ｏｆ Ｍａｔｅｒｉａｌｓ Ｅｎｇｉｎｅｅｒｉｎｇ ｆｏｒ Ｒｅｓｏｕｒｃｅｓ ( 日本素材物性学会 ) advpub ( 0 ) 2026年 [査読有り]
研究論文（学術雑誌） 国内共著
<p>Scratching tests of a diamond substrate were performed using a tool fixed with four types of grains potentially harder than diamond. Materials reported by other researchers to be harder than diamonds often contain combinations of carbon, boron, and nitrogen. From the viewpoint of manufacturing, fullerene, wurtzite (hexagonal lattice boron nitride), polycrystalline diamond, and flame-synthesized diamond were selected in this study. After creating and testing saw wires and wheel saws, flame combustion synthetic diamond was determined to be the most promising. This is because only scratches from flame combustionsynthesized diamond initiate cleavage fracture.</p>
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長尾 晃太, 御代田 竜也, 水間 宏行, 中津 雅延, 岩間 祐一, 鹿住 孝, 七尾 純平, 伊藤 慎一, 髙橋 護, 宮野 泰征, 村田 健司, 神谷 修
日本素材物性学会誌 ( 日本素材物性学会 ) 34 ( 1 ) 20 - 28 2024年05月 [査読有り]
研究論文（学術雑誌） 国内共著
<p>In a series of experiments on a demolition system using a steam pressure cracking（SPC）agent were conducted. The results were obtained by drilling 11 mm diameter（D10 class）rebar in concrete using three types of rake angle bits at the tip of a small rock drill with a power of 2.24 kW （Compressed Air power）. The rebar could be pierced by the rock drill a time of 730～1020 seconds. Thus, it was confirmed that it is possible to process holes for SPC for concrete demolition with reinforcing bars. However, a drilling speed of rebar was about one-fi ftieth of concrete. Observing the steel chips, there are two types of drilling mechanisms. One is a drilling mechanism in which the rebar undergoes compressive deformation at the tip of the bit, and microscopic chips are discharged at the tip of the bit with each impact. The chips are not more than 1 mm wide. The second is to discharge macro chips of several millimeters in size, and the entire rebar is subjected to compressive deformation and because of multiple impacts from the end of the rebar, drilling proceeds in steps.</p>
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Osamu Kamiya, Mamoru Takahashi, Yasuyuki Miyano, Shinichi Ito, Kenji Murata, Makoto Kawano, Arata Maisawa, Jumpei Nanao, Takashi Kazumi, Masanobu Nakatsu, Hiroyuki Mizuma, Tatsuya Miyota, Kota Nagao, Yuichi Iwama
Materials ( MDPI AG ) 16 ( 4 ) 1398 2023年02月 [査読有り]
研究論文（学術雑誌） 国内共著
<jats:p>This study investigated a new dismantling system for concrete structures using a steam pressure cracking agent. We improved the mechanical systems such that it can drill through reinforcing steel bars. Therefore, the control method of the system and shape of the drill tip were improved. When the drill tip is stuck with chips and stopped, it is automatically pulled out and reinserted to recover the rotation. By changing the tip angle of the drill bit from 75° to 90°, it became possible to cut reinforcing bars, which were difficult to cut previously. In addition, we designed a crawler-type mechanical system and improved it such that it can be moved to the appropriate position and operated at any angle. This study revealed that the energy required for the drilling process accounts for more than 90% of the total dismantling energy. Through experiments using an impact hammer drill and observations of fracture surfaces using a three-dimensional scanner, we analysed the characteristics of reinforced concrete. In addition, the feasibility of the design for dismantling reinforced concrete was confirmed based on the determined energy associated with crack propagation.</jats:p>
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Cutting of Diamond Substrate Using Fixed Diamond Grain Saw Wire
Kamiya Osamu, Takahashi Mamoru, Miyano Yasuyuki, Ito Shinichi, Nakatsu Masanobu, Mizuma Hiroyuki, Iwama Yuichi, Murata Kenji, Nanao Junpei, Kawano Makoto, Maisawa Arata, Kazumi Takashi
Materials 15 ( 16 ) 2022年08月 [査読有り]
研究論文（学術雑誌） 国内共著
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Elastic Wave Property of Concrete Decomposed by Steam Pressure Cracking Agent
Osamu Kamiya, Etsushi Okuyama, Mamoru Takahashi, Yasuyuki Miyano, Shinichi Ito, Kenji Murata, Junpei Nanao, Arata Maisawa, Makoto Kawano, Takashi Kazumi, Masanobu Nakatsu, Hiroyuki Mizuma, Yuichi Iwama
Journal of Materials and Applications 2022年05月 [査読有り]
研究論文（学術雑誌） 国内共著
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Demolition of Reinforced Concrete by Steam Pressure Cracking System
Osamu Kamiya, Mamoru Takahashi, Yasuyuki Miyano, Shinichi Ito, Kenji Murata, Makoto Kawano, Arata Maisawa, Junpei Nanao, Takashi Kazumi, Masanobu Nakatsu, Hiroyuki Mizuma, Yuichi Iwama
Journal of Materials and Applications 11 ( 1 ) 2022年03月 [査読有り]
研究論文（学術雑誌） 国内共著
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淡水系の微生物腐食リスク環境における銅の腐食挙動と微生物への作用
宮野 泰征, 若井 暁, 宮永 一彦, 砂場 敏行, 水上 裕貴, 江野 七海
銅と銅合金 ( 日本銅学会 ) 60 ( 1 ) 150 - 156 2021年08月
研究論文（学術雑誌）
<p>Microbiologically influenced corrosion (MIC) is rapid deterioration of structural materials induced by action of microorganisms in environment. In such a case, microbial adhesion and proliferation on material surface is a precursor to corrosion initiation, then if the material is stainless steel, its open circuit potential can be ennobled. Therefore, significant biofilm formation on metal surfaces and open circuit potential ennoblement of corrosion resistant steels are recognized as indicators of MIC risk.</p><p>There are many lab scale studies for the correlation between microbial adhesion on materials and initiation of MIC. However, there are few studies investigating correlation between metallurgical factors of structural materials and microbial amount or flora on the surface in actual environments.</p><p>We are conducting systematic research focused on material types or alloying elements in order to investigate how such metallurgical factors affect microbial activity in field. In this report, the corrosion behavior was examined by corrosion engineering methods such as potential measurement and weight loss evaluation. Then the microbial amount and microbial flora adhered on copper, carbon steel, and stainless steel coupon in a freshwater were evaluated by genetic analysis method.</p>
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Development of fixed grain micro-saw wire and cutting performance
Osamu Kamiya, Kaito Suzuki, Etsushi Okuyama, Naoya Kojima, Jyunpei Nanao, Shinichi Ito, Mamoru Takahashi, Yasuyuki Miyano, Kenji Murata, Takashi Kazumi, Arata Maisawa, Masanobu Nakatsu, Hiroyuki Mizuma, Yuichi Iwama
Journal of Materials and Applications; ISSN (Online) 1 ( 10 ) 43 - 51 2021年02月 [査読有り]
研究論文（学術雑誌） 国内共著
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その場観察技術を利用した微生物腐食研究 ～溶接鋼を対象とした微生物腐食研究の最前線～
Miyano Yasuyuki
溶接学会誌 ( Yosetsu Gakkai Shi/Journal of the Japan Welding Society ) 89 ( 8 ) 561 - 565 2020年11月 [査読有り] [招待有り]
研究論文（学術雑誌） 単著
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新規その場観察技術を適用したステンレス鋼溶接部微生物腐食発生プロセスの可視化と微生物腐食を誘導する金属学的因子の影響解明に関する研究
宮野泰征
溶接技術 66 104 - 105 2018年02月
研究論文（学術雑誌） 単著