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为降低P110级石油套管淬火冷却过程中的内应力,提出“水淬—空冷—水淬”的优化冷却方式,并利用有限元方法对冷却过程中温度、应力场的变化规律和分布状态进行了模拟.模拟结果表明:冷却至7.5s出水时,横截面上最大温差为104℃,空冷结束时断面温度均匀;再次水冷的最大温差为80℃,与7.5s时相比,温差降低了24℃.对于应力,在最初的水冷阶段,从开始到2.5s,切向应力增大,2.5～5.5s,切向应力降低,冷却至5.5s时发生组织转变,此后热应力和组织应力共存,切向应力随冷却进行迅速升高,并在7.5s时达到最大,为563MPa;出水空冷阶段,热应力减小,组织应力消失,13s空冷结束时切向应力分布较均匀,为-11～27MPa;再次入水冷却至13.6s,切向应力再次达到最大,为451MPa,比7.5s时的563MPa降低了112MPa,达到了优化冷却工艺的目的.
In order to reduce the internal stress during the quench cooling process of P110 oil casing, the optimized cooling mode of “water quenching - air cooling - water quenching” was put forward. The variation regularity and distribution of temperature and stress field during cooling The simulation results show that the maximum temperature difference is 104 ℃ when the effluent water is cooled to 7.5s and the cross-section temperature is even at the end of air cooling. The maximum water temperature difference is 80 ℃ again, and the temperature difference is lower than 7.5s Up to 24 ° C. For the stress, in the initial water-cooling phase, the tangential stress increased from 2.5 to 5.5 s in the initial water cooling period, the tangential stress decreased, and the transformation took place after cooling to 5.5 s, after which the thermal and tissue stresses Coexistence, tangential stress increased rapidly with cooling, and reached the maximum at 7.5s, 563MPa; water cooling stage, the thermal stress decreases, the stress of the tissue disappears, the tangential stress distribution at the end of 13s air cooling is more uniform, -11 ~ 27MPa; again into the water cooled to 13.6s, tangential stress once again reached the maximum, 451MPa, 563MPa than 7.5s when reduced by 112MPa, to achieve the purpose of optimizing the cooling process.