巻号一覧
47 巻 (2009)
- 6 号 p. 352-
- 5 号 p. 294-
- 4 号 p. 208-
- 3 号 p. 126-
- 2 号 p. 70-
- 1 号 p. 4-
前身誌
47 巻, 2 号
選択された号の論文の6件中1～6を表示しています
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論文
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柴田 浩司, 緒形 俊夫, 由利 哲美, Arman NYILAS, 藤井 秀樹, 大宮 慎一原稿種別: 論文
2009 年 47 巻 2 号 p. 70-77
発行日: 2009/03/25
公開日: 2009/04/27
ジャーナル フリーAustenitic 304L and 316L steels are important structural materials for containers, tubes and various fields of liquid-hydrogen engineering. But the number of researches on deformation behavior of such steels in liquid hydrogen is much limited comparing to that in liquid helium. Therefore, in the present work, computer simulation of tensile test was carried out for 304L, 316L and 310S steels in liquid hydrogen in order to understand the basic of the deformation of these steels in liquid hydrogen. Tensile tests were conducted under the condition of the constant cross-head speed using round bar specimens. The procedure of computer simulation was almost same as that used in previous works by the present authors. Practical tensile tests did not show serration on the stress-elongation curves of all three steels up to about 40% elongation but thereafter exhibit sudden noticeable serration. However, computer simulation could not reveal such deformation behavior using previous calculation conditions. After discussing the effects of calculation conditions, it was known that the serration which is similar to that observed on the practical stress-elongation curves could be revealed by changing the boiling behavior of liquid hydrogen on the specimen surface. Following such simulation results, it was suggested that the transition from nucleate to film boiling of liquid hydrogen occurs easier than that reported by Brentari et al. The effect of deformation twin on the serration was also discussed, although the details have not been clarified.抄録全体を表示PDF形式でダウンロード (7862K) -
渡辺 尚徳, 高野 則之, 藤井 秀樹原稿種別: 論文
2009 年 47 巻 2 号 p. 78-84
発行日: 2009/03/25
公開日: 2009/04/27
ジャーナル フリーThe rotate bending fatigue tests for type 316L austenitic stainless steel rods were carried out in air and in an electrolyte with electrochemical cathodic hydrogen charging. The electrolyte used was composed of 0. 05kmol•m-3 sulfuric acid with 1. 4kg•m-3 thiourea, and the employed current density was 49Am-2. Fatigue strength was noticeably decreased by hydrogen charging and the fatigue limit disappeared at the number of cycles up to 107. A considerable amount of α' martensite phase was detected on the fracture surface by X-ray diffraction measurement. The electron probe micro analysis made clear that nickel segregation existed in the central part of the rods, from which the fatigue test pieces were taken. In some area, nickel content was as low as 11mass%, which was almost 1mass% lower than the lower limit of the specification of the average nickel content for 316L. It is considered that the area with low nickel content transformed to martensite phase at the fatigue crack tip having high strain when fatigue cracks propagated. As the martensite phase was believed to be vulnerable against hydrogen, it is considered that the nickel segregation was the major cause of the degradation of fatigue properties in the hydrogen circumstance.抄録全体を表示PDF形式でダウンロード (1503K) -
藤井 秀樹, 大宮 慎一原稿種別: 論文
2009 年 47 巻 2 号 p. 85-94
発行日: 2009/03/25
公開日: 2009/04/27
ジャーナル フリーTo accelerate the construction of hydrogen energy society featuring fuel cell vehicles by enlarging the kinds of materials safely used in hydrogen circumstances in addition to JIS SUS316L, several steels having Ni contents lower than SUS316L and Cr contents equivalent to SUS316L are prepared and their tensile properties in high pressure gaseous hydrogen are investigated at room temperature and -40°C. [Ni]+0. 35[Cr] ([Ni] and [Cr] are their concentrations in mass%) is proposed as an indicator to properly indicate whether hydrogen environmental embrittlement (HEE) occurs or not in45MPa hydrogen gas at both temperatures. HEE is basically related to strain-induced martensite having bcc crystallographic structure. However, there are some steels which do not exhibit any significant HEE although noticeable amount of martensite phase forms. In this case, HEE mainly occurs at the later stage of deformation just before fracture. Steels containing more than 12mass% Ni including SUS316L do not show HEE if there is not serious segregation of alloying elements such as Ni, Cr, Mo. It is also indicated that SUS316 probably do not show HEE if more than 12mass% Ni is contained. Furthermore, steels having Ni content close to 10mass%, which corresponds to the lower limit of the standard of JIS SUS316 and AISI 316L, have considerably higher resistance against HEE compared to SUS304 based steels although HEE occurs at the late stage of deformation. It may be possible for them to be used in high pressure hydrogen circumstances if temperature range at which they are used is fully taken into account and small level of HEE is acceptable.抄録全体を表示PDF形式でダウンロード (4236K)
資料
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(水素ガスタンクのライナー材の疲労寿命評価法確立を目下の目的として)尾田 安司, 野口 博司原稿種別: 資料
2009 年 47 巻 2 号 p. 95-99
発行日: 2009/03/25
公開日: 2009/04/27
ジャーナル フリーPDF形式でダウンロード (1183K)
論文
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第1報: 接合手法と同種金属の接合例羽地 龍志, 宮城 清宏, 真壁 朝敏, 末吉 敏恭, 呉屋 守章原稿種別: 論文
2009 年 47 巻 2 号 p. 100-106
発行日: 2009/03/25
公開日: 2009/04/27
ジャーナル フリーElectric resistance welding and arc welding are most important and useful processes among many welding processes for industrial activity. In this study, a new process of electric resistance welding was considered. The process uses Joule heat generated in metal powder inserted between a pair of solid bars. A method of joining materials was examined. The purpose of the present study is that the joining of two kind materials, which have different melting point, is performed by using metal powder as insert material. The unique point of present process is to insert the metal powder between the two solid metals. During the joining, the melting powder metal was diffused into the solid materials. For the joining, the industrial resistance pressure-welding machine was used as an electric current power source. During the joining, the materials were compressed by hydraulic testing machine. The effectiveness of the present study is confirmed by joining two pure-aluminum bars. The joined materials were broken at the solid aluminum, and the tensile strength of the joined material was the same level as the annealed pure-aluminum. From the observation of macroscopic feature of the joint section, the large size of defect, such as void, was not observed. It is concluded that the present method may be applied to the joining of the different materials.抄録全体を表示PDF形式でダウンロード (546K) -
早川 正夫, 木村 恵, 小林 一夫原稿種別: 論文
2009 年 47 巻 2 号 p. 107-114
発行日: 2009/03/25
公開日: 2009/04/27
ジャーナル フリーMicrostructural analyses by field emission-type scanning backscattered electron microscopy on chemical mechanically polished surfaces were performed on a ferritic heat-resisting steel that contained 12mass% chromium and 2mass% tungsten to characterize subgrain structure. The size distributions of the subgrains were quantitativbry evaluated before and after a creep-fatigue testing, respectively, to relate the creep-fatigue property.
As the results, it was shown that subgrains neighboring the prior austenite grain boundaries became coarse during the creep-fatigue testing, while the size of blocks did not change. It is suggested that the coarse subgrains neighboring grain boundaries plays an important role of the creep-fatigue fracture mechanism.抄録全体を表示PDF形式でダウンロード (2099K)
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