| Project/Area Number |
61470062
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
溶接工学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
KUWANA Takeshi Faculty of Engineering, Tohoku University ・Professors, 工学部, 教授 (60005238)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Yoshihiro Faculty of Engineering, Tohoku University・ Research Assistant, 工学部, 助手 (00170796)
KIGUCHI Ryuji Faculty of Engineering, Tohoku University・ Research Assistant, 工学部, 助手 (60005410)
KOKAWA Hiroyuki Faculty of Engineering, Tohoku University ・ Associate Professors, 工学部, 助教授 (10133050)
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| Project Period (FY) |
1986 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥6,700,000 (Direct Cost: ¥6,700,000)
Fiscal Year 1988: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1987: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1986: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Keywords | Arc-welding / Weld metal / Gas-metal reaction / Slag-metal reaction / Nitrogen absorption / Oxygen absorption / Thermodynamics / 冶金物理化学 |
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| Research Abstract |
Gas-and slag-metal reactions during arc-welding processes of metallic materials were studied thermodynamically. The results are as follows:
(1) Iron alloys were gas-tungsten-arc-melted and GTA welded under various atmospheres including nitrogen gas to study the nitrogen absorption of molten iron alloys during welding processes. The nitrogen absorption behaviour of iron alloy during arc-melting or arc-welding did not obey sieverts' law. The nitrogen contents of arc-melted metals were higher than the equilibrium solubilities. The nitrogen content of weld metal was lower than the equilibrium solubility, only when the solubility is high, such as the cases of high chromium alloys or pressurized nitrogen atmospheres. These facts suggest that the presence of high temperature arc and the shortage of reaction time affect the nitrogen content of weld metal. However, the effects of alloying elements on the nitrogen absorption of arc-melted or arc-welded iron alloys were roughly equal to equilibrium ones.
(2) Iron alloys were gas-tungsten-arc-melted and GMA welded under various atmospheres including oxygen. The effects of alloying elements ('silicon, manganese, aluminium, titanium) on the oxygen absorption of weld metal were systematically studied. The mechanisms of oxygen absorption and deoxidation were discussed by examining the composition, morphology, number and amount of oxide inclusions in the weld metals.
(3) Steels were submerged-arc-welded with simplified flux compositions to study slag-metal reactions during welding processes. The effect of flux composition on the oxygen content of weld metal was examined systematically.
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