研究者詳細 - 高橋　宏治

論文 - 高橋　宏治

件数 198 件

3D積層マルエージング鋼の超高サイクル領域における回転曲げ疲労強度特性に及ぼすレーザピーニングの影響

中村元哉、岩坂明彦、古谷佳之、高橋宏治

鉄と鋼 111 ( 1 ) 9 - 19 2025年1月 [査読有り]

担当区分：最終著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本鉄鋼協会単著

Additive-manufacturing technology has attracted attention for the fabrication of components with complex shapes. However, the low fatigue strength of the metals produced via additive manufacturing poses a significant challenge. In this study, rotating–bending fatigue tests were performed on additive-manufactured maraging steel up to the very-high-cycle fatigue (VHCF) range (108 cycles). The effect of laser peening (LP) on the fatigue strength was examined. The LP introduced compressive residual stress near the surface, whereas tensile residual stress was generated internally. The fracture initiation point of the non-LP specimen was observed at the surface in the low-cycle range and in the interior in the VHCF range. In contrast, all the LP specimens fractured from the interior. LP was effective for increasing the fatigue strength in the low-cycle range; however, it reduced the fatigue strength in the VHCF range. The effect of LP on the VHCF strength was examined by focusing on the stress level at the fracture initiation point. Furthermore, the distribution of the defect size on the polished and fractured surfaces of the specimens was evaluated using extreme-value statistics. The results indicated that extreme-value statistics are effective for predicting the defect size in practical applications.

ショットピーニング処理された浸炭鋼の疲労強度に及ぼす素材採取方向の影響

辻俊哉，藤野真士，高橋宏治

砥粒加工学会誌 68 ( 11 ) 624 - 630 2024年11月 [査読有り]

担当区分：最終著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）共著

Fatigue life improvement by shot peening for pre-fatigue tested carburized steel

Fujino Masashi, Tsuji Toshiya, Takahashi Koji

Fatigue & Fracture of Engineering Materials & Structures 47 ( 10 ) 3848 - 3857 2024年10月

DOI CiNii Research

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：John Wiley & Sons Ltd 共著

The effect of shot peening (SP) on pre-fatigue tested carburized steel was investigated. Plane-bending fatigue tests were conducted on carburized CrMo steel that was pre-fatigue tested and treated with SP. Fatigue cracks were induced by pre-fatigue tests with a stress amplitude of σa = 1000 MPa, and the number of the pre-fatigue test cycles was 2.0 × 104 (L5 test) and 4.0 × 104 (L15 test). We compared the fatigue lives of the fatigue-damaged and smooth specimens without fatigue damage treated with the same SP. The fatigue life of the L5 tested specimens with SP was longer than that of the non-fatigue damaged smooth specimens after SP. Therefore, the fatigue cracks introduced by the L5 test can be rendered harmless by SP. Furthermore, near-surface material properties were evaluated and the mechanisms of rendering surface cracks harmless were investigated.

その他リンク： https://doi.org/10.1111/ffe.14414

Fatigue strength improvement of aluminum alloy with surface defect by ball burnishing

Wakamatsu, K; Takahashi, K; Koyama, Y; Taniguchi, M

Fatigue & Fracture of Engineering Materials & Structures 47 ( 9 ) 3464 - 3473 2024年6月 [査読有り]

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論文 - 高橋 宏治

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論文 - 高橋　宏治