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针对倾斜板熔体处理晶粒细化与半固态成形原理,研究了倾斜板熔体处理过程边界层分布, 建立了熔体传热和冷却速率的计算模型.计算结果表明,随着斜板倾角和熔体初始流动速度的增大, 熔体在倾斜板上从层流向紊流的转变时间减少;温度边界层厚度随着熔体初始流动速度的增加而减小, 斜板倾角对温度边界层厚度的影响较小;温度边界层厚度和速度边界层厚度都随熔体流动距离的增加而增大, 在层流区,温度边界层厚度远大于速度边界层厚度,而在紊流区,温度边界层厚度与速度边界层厚度重合; 倾斜板上熔体冷却速率与熔体厚度成反比,初始流速小于1 m/s时,熔体的冷却速率沿着倾斜板长度方向 逐渐增大,初始流速为1 m/s时,熔体的冷却速率沿倾斜板长度方向基本不变,当初始流速大于1 m/s时, 熔体冷却速率沿倾斜板长度方向逐渐减小;倾斜板上熔体冷却速率在100-1000 K/s之间, 属于亚快速凝固范畴.In this paper, according to the principle of grain refining and semisolid forming by cooling sloping plate process, the distributions of boundary layers during melt treatment by the sloping plate are studied, and mathematic models of heat transfer and cooling rate are established. Calculation results show that the change time from laminar flow to turbulent flow decreases with the increases of the sloping angle and initial flow velocity. The thickness of temperature boundary layer decreases with the increases of initial flow velocity. The effect of the sloping angle on the thickness of temperature boundary is small. The boundary layer thicknesses of the both temperature and velocity increase with the increase of the flow distance gradually. In the laminar flow region, the thickness of the temperature boundary layer is much bigger than that of the velocity boundary layer, while the two layers coincide with each other in the turbulent flow zone. The melt cooling rate on the sloping plate and the melt thickness have an inverse proportion relationship between each other. When the initial flow velocity is lower than 1 m/s the cooling rate increases along the sloping plate gradually. While the initial flow velocity is 1 m/s, the cooling rate dose not change approximately. However, when the initial flow velocity is larger than 1m/s the cooling rate decreases along the sloping plate gradually. The melt cooling rate on the cooling sloping plate is between 100 K/s and 1000 K/s, which belongs to meta-rapid solidification scope.
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Keywords:
- semisolid /
- grain refining /
- sloping plate /
- cooling rate
[1] Kaufmann H, Mundl A, Uggowitzer P J, Potzinger R, Ishibashi N 2002 Die Cast. Eng. 46 16
[2] Haga T, Saito M, Kumai S, Watari H 2009 Adv. Mater. Res. 97-101 1057
[3] Haga T, Tkahshi K, Ikawaand M, Watari H 2004 J. Mater. Process. Technol. 153-154 42
[4] Kapranos P, Haga T, Bertoli E, Pola A, Azpilgain Z, Hurtado I 2008 Diffus. Def. Data Pt. B 141-143 115
[5] Grimmig T, Ovcharov A, Afrath C, Bunck M, Buhrig-Polaczek A 2006 Diffus. Def. Data Pt. B 116-117 484
[6] Babaghorbani P, Salarfar S, Nili-Ahmadabadi M 2006 Diffus. Def. Data Pt. B 116-117 205
[7] Xing S M, Zeng D B, Hu H Q, Zhai Q J, Ma J, Li Y M 2000 Foundry 48 449 (in Chinese) [邢书明, 曾大本, 胡汉起, 翟启杰, 马静, 李亚敏 2000 铸造 48 449]
[8] Jiang Y H, Dai C Q, Zhou R 2004 Special Casting and Nonferrous Alloys 6 23 (in Chinese) [蒋业华, 戴长泉, 周荣 2004 特种铸造及有色合金 6 23]
[9] Cardoso Legoretta E, Atkinson H V, Jones H 2008 J. Mater. Sci. 43 5448
[10] Yan X L, Ran Z 2009 Chin. Phys. B 18 4360
[11] Du C, Xu M Y, Mi J C 2010 Acta Phys. Sin. 59 6331 (in Chinese) [杜诚, 徐敏义, 米建春 2010 59 6331]
[12] Yang S M, Tao W Q 2006 Heat Transfer (Beijing: Higher Education Press) pp4-224 (in Chinese) [杨世铭, 陶文铨 2006 传热学 (北京: 高等教育出版社) 第4-224页]
[13] Le Q Z, Cui J Z 2005 The Basic Principles of Transmission (Beijing: Metallurgical Industry Press) pp47-105 (in Chinese) [乐启炽, 崔建忠 2005 传输过程基本原理 (北京: 冶金工业出版社) 第47-105页]
[14] Wang J Y, Chen C L, Zhai W, Jin K X 2009 Acta Phys. Sin. 58 6554 (in Chinese) [王建元, 陈长乐, 翟薇, 金克新 2009 58 6554]
[15] Chen M W, Wang Z D, Sun R J 2007 Acta Phys. Sin. 56 1819 (in Chinese) [陈明文, 王自东, 孙仁济 2007 56 1819]
[16] Zhai W, Wang N, Wei B B 2007 Acta Phys. Sin. 56 2353 (in Chinese) [翟薇, 王楠, 魏炳波 2007 56 2353]
[17] Li Z Q, Wang W L, Zhai W, Wei B B 2011 Acta Phys. Sin. 60 108101 (in Chinese) [李志强, 王伟丽, 翟薇, 魏炳波 2011 60 108101]
[18] Ruhl T, Spahn P, Hellmann G P 2003 Polymer 44 7625
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[1] Kaufmann H, Mundl A, Uggowitzer P J, Potzinger R, Ishibashi N 2002 Die Cast. Eng. 46 16
[2] Haga T, Saito M, Kumai S, Watari H 2009 Adv. Mater. Res. 97-101 1057
[3] Haga T, Tkahshi K, Ikawaand M, Watari H 2004 J. Mater. Process. Technol. 153-154 42
[4] Kapranos P, Haga T, Bertoli E, Pola A, Azpilgain Z, Hurtado I 2008 Diffus. Def. Data Pt. B 141-143 115
[5] Grimmig T, Ovcharov A, Afrath C, Bunck M, Buhrig-Polaczek A 2006 Diffus. Def. Data Pt. B 116-117 484
[6] Babaghorbani P, Salarfar S, Nili-Ahmadabadi M 2006 Diffus. Def. Data Pt. B 116-117 205
[7] Xing S M, Zeng D B, Hu H Q, Zhai Q J, Ma J, Li Y M 2000 Foundry 48 449 (in Chinese) [邢书明, 曾大本, 胡汉起, 翟启杰, 马静, 李亚敏 2000 铸造 48 449]
[8] Jiang Y H, Dai C Q, Zhou R 2004 Special Casting and Nonferrous Alloys 6 23 (in Chinese) [蒋业华, 戴长泉, 周荣 2004 特种铸造及有色合金 6 23]
[9] Cardoso Legoretta E, Atkinson H V, Jones H 2008 J. Mater. Sci. 43 5448
[10] Yan X L, Ran Z 2009 Chin. Phys. B 18 4360
[11] Du C, Xu M Y, Mi J C 2010 Acta Phys. Sin. 59 6331 (in Chinese) [杜诚, 徐敏义, 米建春 2010 59 6331]
[12] Yang S M, Tao W Q 2006 Heat Transfer (Beijing: Higher Education Press) pp4-224 (in Chinese) [杨世铭, 陶文铨 2006 传热学 (北京: 高等教育出版社) 第4-224页]
[13] Le Q Z, Cui J Z 2005 The Basic Principles of Transmission (Beijing: Metallurgical Industry Press) pp47-105 (in Chinese) [乐启炽, 崔建忠 2005 传输过程基本原理 (北京: 冶金工业出版社) 第47-105页]
[14] Wang J Y, Chen C L, Zhai W, Jin K X 2009 Acta Phys. Sin. 58 6554 (in Chinese) [王建元, 陈长乐, 翟薇, 金克新 2009 58 6554]
[15] Chen M W, Wang Z D, Sun R J 2007 Acta Phys. Sin. 56 1819 (in Chinese) [陈明文, 王自东, 孙仁济 2007 56 1819]
[16] Zhai W, Wang N, Wei B B 2007 Acta Phys. Sin. 56 2353 (in Chinese) [翟薇, 王楠, 魏炳波 2007 56 2353]
[17] Li Z Q, Wang W L, Zhai W, Wei B B 2011 Acta Phys. Sin. 60 108101 (in Chinese) [李志强, 王伟丽, 翟薇, 魏炳波 2011 60 108101]
[18] Ruhl T, Spahn P, Hellmann G P 2003 Polymer 44 7625
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