Effects of grain size on ultrasonic attenuation in type 316L stainless steel

Wan, T.; 直江 崇; 涌井 隆; 二川 正敏; 大林 寛生; 佐々 敏信

Materials, 10(7), p.753_1 - 753_17, 2017/07

AA2017-0189.pdf:2.65MB

https://doi.org/10.3390/ma10070753

A lead bismuth eutectic (LBE) spallation target will be installed in the Target Test Facility (TEF-T) in the Japan Proton Accelerator Research Complex (J-PARC). The spallation target vessel filled with LBE is made of type 316 stainless steel. However, various damages, such as erosion/corrosion damage and liquid metal embrittlement caused by contact with flowing LBE at high temperature, and irradiation hardening caused by protons and neutrons, may be inflicted on the target vessel, which will deteriorate the steel and might break the vessel. To monitor the target vessel for prevention of an accident, an ultrasonic technique has been proposed to establish off-line evaluation for estimating vessel material status during the target maintenance period. Basic R&D must be carried out to clarify the dependency of ultrasonic wave propagation behavior on material microstructures and obtain fundamental knowledge. As a first step, ultrasonic waves scattered by the grains of type 316 stainless steel are investigated using new experimental and numerical approaches in the present study. The results show that the grain size can be evaluated exactly and quantitatively by calculating the attenuation coefficient of the ultrasonic waves scattered by the grains. The results also show that the scattering regimes of ultrasonic waves depend heavily on the ratio of wavelength to average grain size, and are dominated by grains of extraordinarily large size along the wave propagation path.

Evaluation of in-pile and out-of-pile stress relaxation in 316L stainless steel under uniaxial loading

加治 芳行; 三輪 幸夫; 塚田 隆; 菊地 正彦; 北 智士; 米川 実; 中野 純一; 辻 宏和; 中島 甫

Journal of Nuclear Materials, 307-311(Part1), p.331 - 334, 2002/12

https://doi.org/10.1016/S0022-3115(02)01204-7

中性子照射と高温水環境の同時作用効果によって生じる照射誘起応力腐食割れ(IASCC)が、軽水炉のみならず水冷却核融合炉の炉内構造材料の主要な関心事の1つとして指摘されている。応力がIASCCのキーファクターの一つであることから、照射条件下で詳細に応力を評価する必要がある。316Lステンレス鋼の引張型試験片を用いた応力緩和試験を288でJMTRにおいて行ってきている。この論文は、316Lステンレス鋼の引張型試験片の炉内及び炉外応力緩和試験結果についてのべ、おもに曲げ試験片を用いて得られたFosterらの文献データとの比較を行った結果についても述べる。さらに実験結果と永川モデルによる解析結果との比較も行った。