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1003 |
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Poster Presentation Prüfung Inspection |
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Hydrogen permeation characteristics of welded 316 stainless steel using nickel welding rod
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Daigo Kobayashi / Tokyo institute of technology, Japan Takahisa Yamazaki / Tokyo Institute of technology, Toshi-Taka Ikeshoji/ Tokyo Institute of technology, Japan Akio Suzumura/ Tokyo Institute of technology, Japan Daigo Kobayashi/ Tokyo Institute of technology, Japan Takafumi Naito/ Tokyo Institute of technology, Japan |
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For establishment of the infrastructure of handling hydrogen safely, for example, a tank of natural gas, a hydrogen gas chamber, a hydrogen fuel cell and a ultra high vacuum chamber, hydrogen permeation phenomena into various materials have been investigated. These tanks and chambers which need no leak of the gas are assembled by welding. We had performed hydrogen permeation test against welded specimens. It is important to prevent from hydrogen embrittlement cracking in the heat affected zone of welded steels. Low carbon stainless steel of 316L was selected for the welded specimen, and it contains 12-15% nickel. The hydrogen permeation rate in nickel at high temperature is higher than stainless steels, although at low temperature atomic hydrogen occludes between nickel atoms. We investigate the work of nickel element near neat affected zone from the view of the hydrogen catalysis. In this study, the hydrogen permeation technique using an orifice and a quadrupole mass spectrometer (QMS) is utilized to measure the hydrogen gas flux in the stainless steel. A stationary hydrogen flux from the stainless steel surface was measured by using a system with an orifice. The hydrogen pressure difference which applied to the specimen was able to maintain constant by constant gas flow rate from the orifice in low pressure vessel. The value of hydrogen permeability, K, at 620K for welded specimen using the nickel welding rod is 3.62 times 10^-12 m2s-1Pa^(0.5). It is 1.9 times grater than that of normal non-welded 316 stainless steel substrate. The value at 520 K for the welded specimen is 7.31 times 10^-14 m2s-1Pa^(1/2). It is as same as that of the non-welded substrate. |