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1、第26卷 第4期2 0 0 5年 8月材 料 热 处 理 学 报TRANSACTIONS OF MATERIALS AND HEAT TREATMENTVol . 2 6 No . 4August2005不同冷却方式下换热系数的测量与计算袁 俭, 张伟民, 刘占仓, 陈乃录, 王鸣华, 徐 骏 (上海交通大学先进热处理与表面改性工程技术研究中心,上海 200030)摘 要:为了研究不同冷却方式下的换热系数,设计了一套可以测量空冷、 水淬以及不同压力下喷气淬火下冷却曲线的试验装置,试验中测量的探头采用120mm120mm20mm奥氏体不锈钢方板。该探头经有限元(FEM)计算验证了其一维传热特性后
2、,用来测量上述几种冷却方式下的冷却曲线,并用反传热法(IHCM)和集中热容法(LHCM)进行换热系数的计算与分析,比较了不同压力下喷气淬火的换热系数。实验结果表明,当毕欧数Bi 011时,集中热容法就不再适用了。空冷的换热系数非常小,一般认为小于200W(m2K) ,这样计算得到的Bi 011时,集中热容法就不再适用了;(3)不同压力下的喷气淬火的换热系数最大值在125200W(m2K)之间,且压力越大,换热系数也越 大。参考文献1 俞佐平,陆 煜.传热学(第三版) .北京:高等教育出版社,1995 ,240.2 顾剑锋,潘健生,胡明娟.介质换热系数的计算机测算J .热加工工艺,1998 ,5
3、:1314.GuJian2feng , Pan Jian2sheng , Hu Ming2juan. Computer measurement and calculation on heat transfer coefficient of quenchants J .Hot WorkingTechnology , 1998 , 5:1314.3 Chen X, Meekisho L , Becker M, T otten G E. A numerical validation of lumped capacitance analysis for deriving heat transfer c
4、oefficient using quenchingprobeC. 17thASM Heat Treating Society Conference Proceedings Including the 1stInternational Induction Heat Treating Symposium. Indianapolis(USA) ,1997 ,355362.4 K im H K, Oh S I. Evaluation of heat transfer coefficient during heat treatment by inverse analysisJ . Journal of
5、 Materials Processing Technology ,2001 ,112: 157165.5 胡亚才,翁海勇,屠传经.集总参数法适用条件研究J .浙江大学学报,1995 , 29(4) :470475.Hu Ya2cai , Wen Hai2yong , Tu Chuan2jing. Investigation in Applicability of lumped2heat2capacity methodJ . Journal of Zhejiang University , 1995 , 29(4) :470475.6 顾剑峰,潘健生,胡明娟.淬火冷却过程中表面综合换热系数的反
6、传热分析J .上海交通大学学报,1998 , 32(2) :1922.Gu Jian2feng , Pan Jian2sheng , Hu Ming2juan. Inverse heat conduction analysis of synthetical surface heat transfer coefficient during quenching processJ .Journal of Shanghai Jiao T ong Unversity , 1998 , 32(2) :1922.7 Oliveira M S A , Sousa A C M. Neural network a
7、nalysis of experimental data for airwater spray coolingJ . Journal of Materials Processing Technology ,2001 ,113:439445.911第4期袁 俭等:不同冷却方式下换热系数的测量与计算has some dependence of the crystal orientation of the surroundingmatrix. With oxidation time prolonging , the spherical voids becomegradually polygonal
8、void and its distribution changes from three2dimensional conical type into two2dimensional plane type. The growthof the voids can be divided into two stages: fast growth and stablegrowth.The depth of voids band first increases quickly and thenunchanged. The formation mechanisms of the voids are disc
9、ussed.Key words: void; interface ; high temperature ; K irkendall effect ;aluminized steelInfluence of Oxidation Temperature on Surface Morphology andMicrostructureofMagnetronSputteredCrTiAliNGradientCoatingsBAI Li2jing1 , 2, JIANG Bai2ling2, WEN Xiao2bin2, ZHANG Guo2jun2, HE Jia2wen1(1. School of M
10、aterial Science and Engineering ,Xian Jiaotong University , Xian 710049 , China ; 2.School ofMaterial Science and Engineering , Xian University of Technology ,Xian 710049 , China)T rans Mater Heat T reat ,2005 ,26(4) :111114 ,figs 5 ,tabs 0 ,refs 9.Abstract: Theeffectofheatingtemperatureonmorphology
11、 ,microstructure and phase components of magnetron sputtered CrTiAliNgradient coatings were studied by SEM and XRD. The results showthat the coating is stable under 600and phase transformationsoccure when the temperatures increase , which is beneficial tohardness, adhesions and toughness of the coat
12、ing.The coatingsurfaces are locally molten when heating to 900, but the adhesive ofthe coating with steel substrate is still very well. When heated at1100, the coating can pull off from the substrates. It is indicatedthat the CrTiAliN coatings have good thermal stable below the 900.Key words:oxidati
13、on; magnetron sputtered; gradient coatingsThe Measurement and Calculation of Heat Transfer Coefficientunder Different Cooling ConditionsY UAN Jian , ZHANG Wei2min , LIU Zhan2cang , CHEN Nai2lu ,WANG Ming2hua , XU Jun ( The Engineering Research Center ofAdvancedHeatTreatmentandSurfaceModification ,Sh
14、anghaiJiaoT ong University ,Shanghai 200030 ,China)T rans Mater Heat T reat , 2005 ,26(4) :115119 ,figs 7 ,tabs 0 ,refs 7.Abstract: In order to determine the heat transfer coefficient underdifferent cooling conditions , an experiment apparatus is designed tomeasure the cooling curves of air , water
15、and different2pressure airspray cooling. A 120mm120mm20mm flat sample , proved to beone2dimension heat conduction by finite element method(FEM) , isadopted for the measurement in this experiment. Both the Inverse HeatConduction Method ( IHCM)and Lumped Heat Capacity Method(LHCM) are used in the calc
16、ulation of heat transfer coefficient. Theresults of air spray cooling are also discussed based on differentpressures. The experiment results indicate that LHCM is applicableonly when Bi 011 and also indicate that during air spray cooling , thehigher the pressure is , the greater the heat transfer coefficient is.Key words:heat transfer coefficient , one2dimension heat conduction ,inverse heat conduction method(IHCM
