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建立了石油套管在淬火冷却过程中温度、应力场的三维非线性热力耦合有限元模型,并分析了温度、应力场的变化规律和分布状态。模拟结果表明:冷却过程中,轴截面沿径向的温差先增加后减小,冷却2.5 s时,温差最大为274℃。冷却至5.5 s时,外表面首先开始发生马氏体转变;当冷却至11.5 s时,套管整体温度≤280℃,几乎完成了马氏体转变。套管切向应力对套管影响作用最明显,在冷却初期,热应力作用使切向应力随温差增大而升高,减小而降低;发生组织转变后,热应力和组织应力共存,随冷却进行切向应力迅速升高,至7.5 s达到最大为561 MPa;完成组织转变后,只有热应力存在,随冷却进行温差减小切向应力亦降低。
A three-dimensional nonlinear coupled thermo-mechanical finite element model of temperature and stress field of oil casing during quench-cooling process is established. The variation and distribution of temperature and stress field are analyzed. The simulation results show that the radial temperature difference between the axial section and the axial section first increases and then decreases, and the maximum temperature difference is 274 ° C when cooled for 2.5 s. When cooled to 5.5 s, the outer surface first began martensitic transformation; when cooled to 11.5 s, the overall casing temperature ≤ 280 ℃, almost completed the martensitic transformation. Tangential stress of the casing has the most obvious effect on the casing. In the initial stage of cooling, the thermal stress causes the tangential stress to increase as the temperature difference increases, decreasing and decreasing. After the transformation, the thermal stress and the tissue stress coexist After cooling, the tangential stress increased rapidly and reached a maximum of 561 MPa after 7.5 s. After the tissue transformation was completed, only the thermal stress existed. As the temperature difference decreased with the cooling, the tangential stress was also reduced.