真空油淬过程中换热系数的测算  

Measurement and calculation of heat transfer coefficient during vacuum oil quenching

作　　者：刘静[1] 李家栋[1] 王昭东[1] 田勇[1] LIU Jing;LI Jia-dong;WANG Zhao-dong;TIAN Yong(The State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819

出　　处：《材料热处理学报》2021年第9期159-164,共6页Transactions of Materials and Heat Treatment

基　　金：国家重点研发计划(2017YFB0305300);中央高校基本科研业务费专项资助项目(N2007005)。

摘　　要：为了获取不同真空油淬工艺条件下的换热系数,对真空油淬换热特性进行研究。采用ϕ40 mm×80 mm不锈钢探头在双室真空油淬炉内进行真空淬火试验,测得多种工艺条件下的冷却曲线。借助INTEMP有限元软件求解热流密度,根据牛顿换热定律计算出换热系数。然后,将其作为边界条件求解淬火过程温度场,可以得到与实测值吻合较好的冷却曲线,验证了换热系数的准确性。最后,比较了不同工艺条件下的换热系数。结果表明:油温升高会使得高温段冷却强度提升,低温段冷却强度略有降低;油面压力的升高会提高淬火油特性温度,显著提升核沸腾阶段的冷却强度;增大搅拌频率对膜沸腾阶段基本无影响,但是可以增强核沸腾和对流换热阶段冷却能力。In order to obtain the heat transfer coefficient under different vacuum oil quenching conditions, the heat transfer characteristics of vacuum oil quenching were studied. The vacuum quenching experiment was carried out in a double chamber vacuum oil quenching furnace with a stainless steel probe of ϕ40 mm×80 mm, and the cooling curves under various process conditions were measured. With the help of INTEMP finite element software, the heat flux was solved, and the heat transfer coefficient was calculated according to Newton’s heat transfer law. Then, taking it as the boundary condition to solve the temperature field of quenching process, the cooling curve which was in good agreement with the measured value could be obtained, and the accuracy of heat transfer coefficient was verified. Finally, the heat transfer coefficients under different process conditions were compared. The results show that the increase of oil temperature will increase the cooling intensity in the high temperature stage and decrease the cooling intensity in the low temperature stage. The increase of oil surface pressure can increase the characteristic temperature of quenching oil and significantly enhance the cooling intensity in nucleate boiling stage. Increasing the stirring frequency has little effect on the film boiling stage, but can enhance the cooling capacity of nucleate boiling and convective heat transfer stages.

关 键 词：真空油淬 反传热法 换热系数 

分 类 号：TG156.3[金属学及工艺—热处理]