2019 Fiscal Year Final Research Report
Boiling heat transfer on optimization of metal crystal grain refinement and ductility improvement of steel:quench of liquid film
| Project/Area Number |
17K06207
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | Kogakuin University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
長谷川 浩司 工学院大学, 工学部, 准教授 (90647918)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | 熱伝達 / 沸騰 / 金属結晶微粒子化 / 熱力学過熱限界温度 / 濡れ開始温度 / 二次元温度場計測 / 赤外線放射温度計 / 高速度撮影 |
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| Outline of Final Research Achievements |
As the heating surface, a silver flat plate, a transparent sapphire plate and a quartz glass plate were used. Image analysis of the direct observation results from the back side of the heated surface of sapphire and quartz glass was performed. In the experiment, the heating surface heated to 600°C was unsteady cooled with a water nozzle, and the appearance of cooling at this time was measured with an infrared thermography and a high-speed video camera to quantify the wetting start condition. As a result, with respect to the wetting onset temperature, silver is close to the thermodynamic limit superheat. Sapphire was close to the thermodynamic superheat limit temperature under liquid subcooling conditions of 0 and 10K, and about 600℃ under liquid subcooling conditions of 30 and 50K. In the case of quartz glass, the temperature is about 600℃, which is higher than the thermodynamic limit superheat regardless of the liquid subcooling degree.
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| Free Research Field |
伝熱工学
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| Academic Significance and Societal Importance of the Research Achievements |
目的は、沸騰冷却分野の面より、次世代鉄鋼材料創製技術を構築するものである。すなわち、鉄鋼業界では、高強度でかつ延性に優れた材料の生産が強く求められている。そのためには、圧延プロセスと熱処理技術を融合させて、金属結晶の成長を熱制御し、結晶の微粒子化を図ると同時に延性を持たせるための熱処理が欠かせない技術となる。つまり、結晶の微粒子化が高強度化を図る上で重要な因子ではあるが、結晶の微粒子化は、延性が著しく低下し、圧延加工が困難になる。それ故、強度と延性のバランスを取りながら加工、すなわち、鉄鋼を冷却するための技術開発が鉄鋼材料分野での長年の課題となっている。そのため沸騰冷却分野の研究が必要となる。
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