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Mechanical Approach to Fracture Toughness Improvement for High Strength Steel and Its Weld HAZ by Controlling Morphology of Microstructure

Research Project

Project/Area Number 07555666
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section展開研究
Research Field Material processing/treatments
Research InstitutionOsaka University

Principal Investigator

TOYODA Masao  Osaka University, Faculty of Engineering, Professor, 工学部, 教授 (00029191)

Co-Investigator(Kenkyū-buntansha) SUZUKI Suichi  Sumitomo Metal Ind., Steel Sheet & Plate Planning Section, Manager, 鹿島製鉄所・厚板管理室, 室長(研究者)
NAGAE Moriyasu  NKK Corp., Materials and Processing Research Center, Manager, 総合材料技術研究所・福山研究所, 課長(研究者)
KAWABATA Fumimaru  Kawasaki Steel Corp., Heavy Steel Products Research Dept., Manager, 鉄鋼研究所・厚板・条鋼研究室, 課長(研究者)
HAGIWARA Yukito  Nippon Steel Corp., Steel Research Lab., General Manager, 鉄鋼研究所, 部長(研究者)
MINAMI Fumiyoshi  Osaka University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (60135663)
SHIMIZU Masato  Kobelco Research Ins., Contracted Research Division, Manager
Project Period (FY) 1995 – 1997
Project Status Completed (Fiscal Year 1997)
Budget Amount *help
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000)
KeywordsDual-Phase Steels / Local Heterogeneity / Brittle Fracture / Fracture Toughness / Controlling Microstructure / Stress-Strain analysis / Local Approach / Material Design / 破壊靭性 / 高強度鋼 / 溶接熱影響部 / 局部的劣化部 / CTOD試験 / 応力・歪解析
Research Abstract

This study discussed the transfer of local stress fields in microstructures to fracture property evaluation of structural steels. Initiation behavior of brittle microcrack in dual-phase steels was mainly focused. The Weibull stress employed in the local approach is available for the evaluation of fracture driving force of each microstructure in dual-phase steels. The idea in this procedure is the integration of local stress in the microstructure responsible for fracture initiation. The local stress in dual-phase steels can be different considerably from a macroscopic stress obtained from the global analysis of specimen. Generally, the high-strength phase bears larger stress than the low-strength phase, which means that fracture property evaluation based on the global stress field is not always reliable. The local stress in the microstructure is affected by the morphology of second phase and matrix. Increase in strength and slenderness of hard phase leads to elevation of fracture driving force of the hard phase. The stresses in low-strength phase can be relaxd to a large extent, provided that the low-strength phase is enclosed by the high-strength phase. These microscopic characteristics of stress fields are important in the fracture control design of structural steels. The Weibull stress is expected as a measure to link between microscopic and macroscopic aspects of fracture.

Report

(4 results)
  • 1997 Annual Research Report   Final Research Report Summary
  • 1996 Annual Research Report
  • 1995 Annual Research Report
  • Research Products

    (19 results)

All Other

All Publications (19 results)

  • [Publications] 鈴木 秀一, 別所 清, 豊田 政男, 南 二三吉: "多層溶接熱影響部における島状マルテンサイトの形態と破壊特性-強度的不均質をもつ鋼溶接部のミクロき裂発生特性に関する研究(第一報)-" 溶接学会論文集. 13-2. 293-301 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 鈴木 秀一, 別所 清, 豊田 政男, 南 二三吉: "特性分布図による溶接熱影響部CTOD靱性の解釈-強度的不均質をもつ鋼溶接部のミクロき裂発生特性に関する研究(第二報)-" 溶接学会論文集. 13-2. 302-308 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] F.Minami, M.Toyoda, C.Thaulow, M.Hauge: "Effect of Strength Mis-Match on Fracture Mechanical Behavior of HAZ-Notched Weld Joint" 溶接学会論文集. 13-4. 508-517 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 野口 泰隆, 南 二三吉, 豊田 政男, 島貫 広志: "フェライト・マルテンサイト二相鋼の破壊特性に及ぼす組織形態の影響" 溶接学会全国大会講演概要. 59. 210-211 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 野口 泰隆, 加藤 孝憲, 南 二三吉, 豊田 政男, 島貫 広志: "微視的強度不均質材の破壊発生特性に及ぼす不均質形態の影響に関する解析" 溶接学会全国大会講演概要. 60. 140-141 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 南 二三吉, 大畑 充, 豊田 政男, 有持 和茂: "破壊靱性試験の構造性能評価へのTransferabilityを考慮した破壊靱性要求-破壊制御設計へのローカルアプローチの展開(第1報)-" 日本造船学会論文集. 182. 647-657 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 南 二三吉, 大畑 充, 豊田 政男, 有持 和茂: "微視的強度不均質に注目した鋼材破壊特性の高機能化へのアプローチ-破壊制御設計へのローカルアプローチの展開(第2報)-" 日本造船学会論文集. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Shuichi Suzuki, Kiyoshi Bessyo, Masao Toyoda, Fumiyoshi Minami: "Influence of Martensitic Islands on Fracture Behavior of Multipass Weld HAZ-Study on Micro-crack Initiation Properties in Steel HAZ having Microscopical Heterogeneity in Strength (Report 1) -" Journal of the Japan Welding Society. Vol.13 No.2. 293-301 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Shuichi Suzuki, Kiyoshi Bessyo, Masao Toyoda, Fumiyoshi Minami: "Property Distribution Map to understand HAZ CTOD Toughness -Study on Micro-crack Initiation Properties in Steel HAZ having Microscopical Heterogeneity in Strength (Report 2) -" Journal of the Japan Welding Society. Vol.13, No.2. 302-308 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Fumiyoshi Minami, Masao Toyoda, Christian Thaulow, Mons Hauge: "Effect of Strength Mis-Match on Fracture Mechanical Behavior of HAZ-Notched Weld Joint" Journal of the Japan Welding Society. Vol.13, No.4. 508-517 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Yasutaka Noguchi, Fumiyoshi Minami, Masao Toyoda, Hiroshi Shimanuki: "Microcrack Initiation and Propagation in Ferrite-Martensite Dual Phase Steels" Preprints of the National Meeting of J.W.S. Vol.59. 140-141 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Yasutaka Noguchi, Takanori Katou, Fumiyoshi Minami, Masao Toyoda, Hiroshi Shimanuki: "Numerical Analysis of Fracture Initiation Behaviors of Materials with Microscopic Heterogeneity" Preprints of the National Meeting of J.W.S. Vol.60. 210-211 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Fumiyoshi Minami, Mitsuru Ohata, Masao Toyoda, Kazusige Arimochi: "Determination of Required Fracture Toughness of Materials Considering Transferability to Fracture Performance Evaluation for Structural Components-Application of the Local Approach to Fracture Control Design (Part 1)" JI.Soc.Naval Archit.Vol.182. 647-657 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Fumiyoshi Minami, Takanori Katou, Yasutaka Noguchi, Daizo Terai, Masao Toyoda, Hiroshi Shimanuki: "Fracture Property Improvement of Structural Steel by Local Stress Control in Dual-Phase Microstructure-Application of the Local Approach to Fracture Control Design (Part 2)" JI.Soc.Naval Archit.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 野口泰隆, 加藤孝憲, 南二三吉, 豊田政男, 島貫広志: "微視的強度不均質材の破壊発生特性に及ぼす不均質形態の影響に関する解析" 溶接学会全国大会講演概要. 60. 210-211 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 南二三吉, 加藤孝憲, 野口泰隆, 寺井大造, 豊田政男, 島貫広志: "微視的強度不均質材に注目した鋼材破壊特性の高機能化へのアプローチ" 日本造船学会論文集. 183. 印刷中につきページ未確定 (1998)

    • Related Report
      1997 Annual Research Report
  • [Publications] 野口泰隆,南二三吉,豊田政男,島貫広志: "フェライト・マルテンサイト-相鋼の破壊特性に及ぼす組織形態の影響" 溶接学会全国大会講演概要. 59. 140-141 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 鈴木秀一,別所清,豊田政男,南二三吉: "多層溶接熱影響部における島状マルテンサイトの形態と破壊特性" 溶接学会論文集. 13. 293-301 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] 鈴木秀一,別所清,豊田政男,南二三吉: "特性分布図による溶接熱影響部CTOD靱性の解釈" 溶接学会論文集. 13. 302-308 (1995)

    • Related Report
      1995 Annual Research Report

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Published: 1996-04-01   Modified: 2016-04-21  

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