巻号一覧
47 巻, 2 号
選択された号の論文の5件中1～5を表示しています
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加藤 剛志, 小野 清雄, 河野 富夫, 清水 孝純1976 年 47 巻 2 号 p. 70-77
発行日: 1976/04/15
公開日: 2009/05/25
ジャーナル フリーUsually stainless steels are susceptible to severe crevice corrosion under marine organisms immersing in sea water. For a method of assessing the susceptibility to the crevice corrosion in sea water, anodic polaization measurements were performed on the specimens containing an artificial crevice contacted with silicon rubber in 3% NaCl solution at 35°C. The relationship between the corrosion weight loss in sea water and crevice corrosion potentials determined by anodic polarization curves has been investigated.
The results obtained are summarized as follows.
(1) A method of measuring the crevice corrosion potentials has good reproducibility, and forms of crevice corrosion observed under the marine organisms after immersion test in sea water and under silicon rubber after measuring the anodic polarization curves are identified.
(2) It is shown that the corrosion weight loss immersing in sea water are in good agreement with crevice corrosion potentials determined by electrochemical measurement. so that crevice corrosion potential measurement is very useful in predicting the corrosion behavior of stainless steels in sea water.
(3) It is shown that the stainless steels exhibiting more noble crevice corrosion potentials than 0.32V vs SCE are not attacked in sea water for 12 months.
(4) On the basis of immersion test results in sea water and measuring the crevice corrosion potentials, the order of the resistance to the localized corrosion of stainless steels in sea water is in the following: 26Cr-1Mo>23Cr-6Ni-1.5Mo-Nb>17Cr-11Ni-3Mo-N>SUS316>316L>316F>304>26Cr>304L>430.抄録全体を表示PDF形式でダウンロード (6674K) -
斉藤 誠, 伊藤 幸生1976 年 47 巻 2 号 p. 78-87
発行日: 1976/04/15
公開日: 2009/05/25
ジャーナル フリーIn order to improve the tray life, some thermal fatigue properties are to be examined: they are the effect of maximum temperature, grain size, structure change and casting defects.
Further, the relation between data of thermal fatigue test and practical life of tray was investigated.
The results obtained are as follows:
(1) From the standpoint in choosing tray materials SCH13 B type is superior to A type.
(2) Effect to thermal fatigue life of slag inclusion is more harmful than that of microshrinkage. The fluctuation of thermal fatigue life is mainly caused by the size of slag inclusion.
(3) There is a good agreement between practical tray life and the data of thermal fatigue life. This type of thermal fatigue tests is used as the measure to improve trays.抄録全体を表示PDF形式でダウンロード (12317K) -
磯部 晋, 宗 光彦1976 年 47 巻 2 号 p. 88-97
発行日: 1976/04/15
公開日: 2009/05/25
ジャーナル フリーThe relationship between microstructures and ductility at room temperature in 50% Cr-Ni casting was studied.
Results are as follows:
(1) Ductility at room temperature lowers as casting get thicker and cooling rates lower.
(2) As cooling rates get lower, the colony of cellular precipitate occupies greater portion on the microstructure, but the amount of primary α1 (Cr-rich solid solution) shows no variation.
(3) The cellular precipitate takes place with grain boundary reaction (GBR), not with eutectic reaction.
(4) Ductility at room temperature can be improved by heat treatment, at which α (Cr-rich) precipitates in GBR dissolve into matrix γ1.抄録全体を表示PDF形式でダウンロード (9285K) -
磯部 晋, 宗 光彦1976 年 47 巻 2 号 p. 98-104
発行日: 1976/04/15
公開日: 2009/05/25
ジャーナル フリーTo develop an alloy whose 100hr creep-rupture strength at 1000°C is 3.5kg/mm2, statistical design and analysis of optimum seeking experiments were conducted.
From this program the following results were obtained;
1) With regard to 100hr creep-rupture strength at 1000°C, the composition was optimized by the statistical experimentation as follows; 0.20%C, 1.0%Si, 1.5%Mn, 30%Ni, 20%Cr, 3%Mo, 1%W, 1%Nb.
2) The heat containing the above composition showed 3.92kg/mm2 as 100hr creep-rupture strength at 1000°C, which was beyond the target and very close to the calculated value.抄録全体を表示PDF形式でダウンロード (3142K) -
阿部 直弘, 河野 富夫, 藤倉 正国, 寺井 和人1976 年 47 巻 2 号 p. 105-114
発行日: 1976/04/15
公開日: 2009/05/25
ジャーナル フリーThe microscopic structural investigation was made to explain about the pitting corrosion resistance of a ferrite-austenite stainless cast steel DCS1.
Temperature for solution treatment was from 900 up to 1150°C and sensitization was made between 500 to 1050°C after solution treatment at 1080°C.
The results are as follows:
(1) The corrosion rate of DCS1 decreases when solution treatment temperature increases. But it becomes less than 2(mg/cm2) in case the temperature is over 1080°C.
(2) When cooling rate is slow, chromium carbide Cr23C6 and sigma phase recipitate at the ferrite-austenite grain boundaries and in the ferrite grains. These precipitations cause the selective corrosion and in this case the corrosion rate increases largely.
(3) The time-temperature-sensitization curve of DCS1 consists of two C curves with nose temperature at 850°C and 700°C. The high temperature nose results from the precipitation of sigma phase at the ferrite-austenite grain boundary and in the ferrite grain. The lower nose is the sensitization caused by the precipitation of chromium carbide at the ferrite-austenite grain boundaries.
(4) With the cooling rate of water quenchd specimen from 1080°C, solution treatment can be done without sensitization up to the thickness of 100mm.抄録全体を表示PDF形式でダウンロード (17128K)
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