Improvement of Fatigue Strength of Welded Joints by Grain Refinement Using Laser Irradiation and Locally Carburized

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  • 寺辻, 和陸
    九州大学大学院工学府船舶海洋工学専攻 : 大学院修士
  • 村上, 幸治
    九州大学工学部技術部 : 技術専門職員
  • 松田, 和貴
    九州大学大学院工学研究院海洋システム工学部門 : 准教授
  • 後藤, 浩二
    九州大学大学院工学研究院海洋システム工学部門 : 教授

説明

The purpose of this paper is to confirm fatigue strength of welded joints can be improved by grain refinement using laser irradiation and localized carburization considering corrosion and abrasion. / Comparing measured temperature history of laser irradiation with theoretical solutions of moving heat source and instantaneous line heat source, and effective temperature range of grain refinement are investigated. Only moving heat source agreed with the measured values. Maximum temperature and time required from 800 ℃ to 500 ℃ (Δt8/5) of the grain refinement region are obtained by applying moving heat source. It is reasonable based on the theory of phase transformation. / Four-point bending fatigue tests were conducted on T-joint specimens as welded, laser irradiated, and locally carburized. As a result, number of cycles to failure of the specimens which locally carburized and laser irradiated were equivalent and they are longer than that of the specimens as-welded. The main reason is locally carburized and laser irradiated had more gentler toe shapes than as-welded. However, the porosity was observed in the carburized specimen. It can affect fatigue strength, further improvement of fatigue strength was expected by eliminating it.

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詳細情報 詳細情報について

  • CRID
    1050298532702988928
  • HANDLE
    2324/7157262
  • 本文言語コード
    en
  • 資料種別
    conference paper
  • データソース種別
    • IRDB

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