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1995 Fiscal Year Final Research Report Summary

Mechanism of Environmental Assisted Cracking by the AE Source Inversion and Moment Tensor Analyzes

Research Project

Project/Area Number 06650811
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Material processing/treatments
Research InstitutionAoyama Gakuin University

Principal Investigator

TAKEMOTO Mikio  Aoyama Gakuin University, Faculty of Science and Engineering, Professor, 理工学部, 教授 (40082838)

Project Period (FY) 1994 – 1995
KeywordsAcoustic Emission / Source Inversion / Moment Tensor Analysis / Radiation Pattern / APC-SCC / Expermental Trasnfer Function / Heat Resistant Capacitive Sensor
Research Abstract

Aming to clarify the mechanism of the so-called active path corrosion type stress corrosion cracking (APC-SCC), eight channel acoustic emission (AE) monitoring was attempted. The AE source inversion, moment tensor and radiation pattern analysis of the longitudinal waves revealed that the successive or multiple intergranular crackings were involved in the SCC of austenitic stainless steel AISI 304 by the polythionine acid solution at ambient temperature. Moment tensor analysis of the AE waves, however, showed an abnormal result because all sensors could not monitor the longitudinal wave emitted by the first fracture The out-of-plane displacement computed for two-step generation of microcracks was found to agree well with the monitored one.
It was first demonstrated that the chloride-SCC of the AISI304 steel at 140C was associated with the transgranular brittle fracutre. We also proposed a new method to determine the experimental trasnfer function of the compact tension specimen. The out-of-plane displacement computed using the experimental transfer function of the specimen sharply agreed with the monitored one, and indieated that the extremely fast cracking, almost 10^7 times that of average SCC propagation rate, occured even in the transgranular chloride-SCC.
The mechanism of the molten chloride salt and fused zinc attack of AISI 304 steel at 600C was also examined using the developed heat resistant capacitive AE sensor. Multiple cleavage type crackings were firstly revealed to occur even in these high temperature attacks.

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] 竹本誠・林康久・竹本幹男: "弾性波動のモーメントテンサー解析によるθT処理低合金鋼の水素脆性割れのメカニズム" 材料と環境. 43. 510-579 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 竹本誠・林康久・竹本幹男: "AE原波形解析とモーメントテンソル解析による低合金鋼の水素脆性割れのダイナミックス" 非破壊検査. 42. 637-644 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 竹本幹男・中沢知之: "いわゆる"活性経路アノード溶解型応力腐食割れ"のメカニズム" 材料と環境. 44. 166-173 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 竹本幹男: "鋼が水素吸蔵中に発生する弾性波に関する一考察" 材料と環境. 44. 494-504 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 大出克久・林健太郎・竹本幹男: "分散性弾性波の順解析による高温環境劣化割れのメカニズム-第1報耐熱AEセンサーの試作とレーザー超音波による高温音協特性の非防疫検査" 材料と環境. 44. 674-682 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 林健太郎・竹本幹男: "第2報;引張り応力下におけるSUS304ステンレス鋼の溶融塩化物割れのAEモニターリング" 材料と環境. 45. 2-10 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M.Takemoto, Y.Hayashi and M.Takemoto: "Francture Mechanism of Hydrogen Assisted Cracking of a QT-treated Low Alloy Steel Estimated by AE Moment Tensor and Source Wave Analysis" Zairyo-to-Kankyo. 43. 670-679 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Takemoto, Y.Hayashi and M.Takemoto: "Fracture Dynamics of Hydrogen Assisted Cracking of a Low Alloy Steel Estimated by AE Source Characterization and Moment Tensor Analysis" J.Non-destructive Testing, Japan. 43. 637644 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Takemoto: "Consideration on the Elastic Waves Emitted by the Steel Absorbing Hydrogen" Zairyo-to-Kankyo. 44. 494-504 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Takemoto and T.Nakazawa: "Mechanism of the So-called Active Path Corrosion Type Stress Corrosion Cracking" Zairyo-to-Kankyo. 44. 166-173 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Oide, K.Hayashi and M.Takemoto: "Mechanism of High Temperature Enironmental Assisted Cracking by the Forward Processing of Dissipative Waves Development of The Heat Resistant AE Sensor and Non-destructive Estimation of Acoustic Properties of Hot Medium by the Laser Ultrasonic." Zairyo-to Kankyo. 44. 674-682 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Hayashi and M.Takemoto: "Mechanism of High Temperature Enironmental Assisted Cracking by the Forward Processing of Dissipative Waves-AE Monitoring of the Molten Salt Cracking of Tensile Stressed SUS 304 Stainless Steel" Zairyo-to-Kankyo. 45. 2-10 (1996)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1997-03-04  

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