著者

布村 成具

出版者

一般社団法人 軽金属学会

雑誌

軽金属 (ISSN:04515994)

巻号頁・発行日

vol.28, no.11, pp.566-574, 1978-11-30 (Released:2008-07-23)

参考文献数

32

被引用文献数

1

著者

堀川 一男 梅沢 義信 世良 真一 合田 孝純 中島 貞一 足立 彰 水川 清 作井 誠太 中村 正久 布村 成具 大森 正信 藤原 達雄

出版者

一般社団法人 日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.47, no.3, pp.418-430, 1961-03-01 (Released:2010-10-12)

著者

作井 誠太 中村 正久 布村 成具 藤原 達雄

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.49, no.4, pp.672-679, 1963-04-01 (Released:2010-10-12)

参考文献数

7

被引用文献数

3

---

The effect of the specimen width on the Charpy test was studied with specimens of hotrolled mild steel and quenched-and-tempered medium carbon steel, by recording the load-time relations under impact bending. Results obtained were summarized as follows:(1) The energy absorption in the ductile range was influenced by the specimen-width smaller than 4mm-the smaller the width, the lower the energy absorption per unit sectional area and it was found that the law of similarity was not satisfied in this case. On the contrary the maximum fiber fracture strength was almost constant for all the specimens, showing the applicability of the law of similarity.(2) Maximum fiber bending stress in fracture was the largest in the temperature range where the absorption energy was decreased almost to minimum value and the load-time curve of type I designated by the authors in the previous papers was obtained. (Tetsu-to-Haganeé 46 (1960) p. 141, 1538; Tetsu-to-Haganeé Overseas, 1 (1961) p. 38).(3) The brittle specimens tempered at a rather lower temperature after quenching, showed the type I or 11 load-time curves over all the testing temperature, and thus fractured thoroughly with only a crack, once started. It was found that in these tests the fracture strength scattered considerably.(4) The notch shape had an influence on the absorption energy for ductile fracture of the less ductile specimens with tempered martensite. It was concluded that the above effect was mainly due to the difference of the amount of deformation produced until the crack formation.(5) The transition temperature showed the same tendency to the changes of specimenwidth under any definition, rising as the width increased. However, the change of the transition temperature for the specimen-witdh larger than 6mm showed the considerablly different tendency from that of the specimen smaller than 4mm. Therefore, in the application of subsize specimen, it is desirable to use the specimen-width larger than 6mm. The effect of specimen-width on transition temperature was affected markedly by the types of the steels and their microstructures.

著者

作井 誠太 中村 正久 布村 成具

出版者

The Iron and Steel Institute of Japan

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.48, no.1, pp.28-34, 1962-01-01 (Released:2010-02-22)

参考文献数

7

被引用文献数

4 1

---

This paper describes of the influences of deformation rate of wide range on the tensile impact properties of several steels by using a high-speed impact-tensile testing machine with a large rotary disk. The deformation rate was varied from static region to 80m/s, and the testing temperature from room temperature to 800°C. The results obtained were summarized as follows:(1) Blue brittleness was observed clearly in mild steel and two alloy steels, and temperature range of blue brittleness shifted to higher temperature with increasing rate of deformation. This shift was conspiquous up to a speed of deformation of 10m/s, but was decreased beyond this speed. Moreover, at the speed of 40m/s the blue brittleness temperature was decreased on the contrary.(2) The similar dependence on deformation rate was also made clear, with regard to the brittleness of 18-8 stainless steel which was due to the effect similar to that causing blue brittleness as well as the brittleness of pure copper at elevated temperature.(3) At higher temperature over 600°C, the critical impact velocity was not observed so distinctly as obtained at room temperature. Tensile strength was lowered with a larger scattering as the deformation rate was increased, while, correspondingly, the value of elongation or reduction of area showed tendency to be rather larger. This phenomenon, named by the authors as “high-rate deformation softening”, was discussed in relation to the loadtime curves observed experimentally.

著者

布村 成具 山中 昇 下条 雅幸 熊井 真次 肥後 矢吉 福井 泰好

出版者

東京工業大学

雑誌

試験研究(B)

巻号頁・発行日

1992

---

KISCC(応力腐食割れ臨界応力拡大係数)は厳しい環境下での構造物の機械的機能を保証する指標とし重要な値である。その物理的意味は確立しているが、統計的バラツキと時間に依存する因子を含むため、この値を高精度に求めるためには過大な設備労力と時間が必要とされるのが現状である。KISCCを高効率にに求める方法を開発して、十分な量のKISCC試験の実行可能にして厳しい境下で用いられる構造物や機械要素の安全を確保することをこの研究の目的とした。本機の試作の成果を検証するためには長時間計測が必要であり、循環系及び計測系をを整備し、長時間安定に関する各種の検討実験を行った。無人計測系の整備は市販ソフト及び研究室開発ソフトによて行っているが、一長一短があり、目的とした市販パソコン程度の機器による信頼性の高い汎用手法の確立がまだなされていない。極微電圧の計測に用いるアナログ回路のノイズの統計的な除去に別のアルゴリズムの適用が必要と思われる。これらの検討はすでに準備された機器、ソフトを駆使して解決出来るものと考える。高力アルミニウム合金の3%NaCl溶液中でKISCC試験を続行され、貴方のデータの確認を行った。破面からのき裂伝播による情報と計測速度を関連づけるべく数百の破面SEM写真の画像解析を行った。この関連は現在のところあまり明瞭でなく、より高度(トンネル顕微鏡、原子間力顕微鏡)の観察に基づく必要があると結論づけられた。き裂伝播速度を測定しない超集積8試片の試験の可能な装置の設計を行った。分担研究者山中はアルミニウム基シラス傾斜機能複合材料の食塩水中でKISCC試験を行こない、プラトウ域のき裂伝播速度とシラス傾斜配分の関連を検討し、地域の要望の高いこの材料の実用化を図った。付加電位によるき裂先端挙動を解析し加速試験の可能性の検討及び腐食環境中のアコーステックエミッション法によるき裂検出精度の改善は、有意な結果は得られなかった。予定した3000時間試験は装置の安定性より行えなかった。研究場所を代表者の新職場に移し、これを完成させる。

著者

布村 成具 山崎 泰広 大滝 秀治

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.50, no.10, pp.1102-1107, 2001-10-15

---

Fatigue characteristics are of fundamental importance when choosing a structural materials, especially when deciding upon the materials for reactor structure where long-term safety is primary importance. In this field, recently, the propagation behavior of mode II and mode III fatigue cracks has attracted special interest. The mode II and mode III fatigue testings involve greater difficulties compared with the mode I testing and the testing procedure has not been established. SS400 carbon steel was fatigue tested by a torsion fatigue testing machine. In the torsion test, fatigue cracks can propagate in all modes. To identify their behavior, surfaces of the specimen were observed by CCD camera and the behavior of surface cracks were recorded in a time-lapse video recorder which can record up to for 40 days. To reveal the morphology of the mode II and mode III Crack propagation, some of test interrupted specimens were sliced and observed by a two dimension measuring microscope. To investigate the crack morphology three dimension crack demonstrate computer program was developed. In the torsion test of plain surface specimen the mode II crack initiates first, but it transits to mode I in the early stage. However, according to the 3D view a large mode III crack propagates into inside in this stage. Persistent slip band like patterns were observed on the surface and the cross section of the fatigue cracked specimen and all mode III cracks propagate in the band. Some of them grew across the center of the specimen. The da/dN – ΔK diagram of the surface mode II fatigue crack propagation was compared with that of mode I by CT type specimen of the same material. Mode II Propagation rate agreed with mode I propagation rate where the stress intensity factor range was converted as ΔK_I= 2ΔK_II. It means that to design the structure by mode I crack propagation data alone may be acceptable under above conversion. To establish this relationship and to elucidate the behavior of mode III fatigue cracking, more investigations are required.