空心圆柱体GCr15钢淬火过程的计算机模拟

Numerical Simulation of the Quenching Process of GCr15 Steel Tube

用有限元法研究了GCr1 5钢圆柱体在油淬过程中的温度、组织及应力变化。在实测了淬火油换热系数的基础上 ,对轴对称空心圆柱体淬火时的温度场和组织场进行了模拟。同时运用热弹塑性理论 ,对圆柱体内外表面点及中心点应力的演化过程进行了模拟。模拟结果表明 :圆柱体内表面的冷速小于外表面。在淬火初期 ,由于热应力的作用使工件表面受拉而心部受压 ,在发生应力反向前 ,发生了组织转变 ,并使表面应力迅速转向 ,在应力达到最低点后又逐渐回升 ,最后表面形成了拉应力。心部的应力变化正好相反 ,最终形成了组织应力型的内应力分布。

A coupled thermal, structural and mechanical model was established to study the oil quenching process of GCr15 tube using Finite Element Method. After determining the heat transfer coefficient of oil, the temperature, microstructure and stress variations during quenching were analyzed. The results show that the cooling rate of the inner surface is slower than that of the outer surface. In the initial stage of quenching, the surfaces are in tensile and the core is in compressive because of the thermal stress. Under the effect of structural stress due to phase transformation, the axial stress in the surface is reversed to negative rapidly, and after reaching the nadir, gradually bounded back to positive. The stress variation in the center is just opposite, and a structural type internal stress state is formed after quenching.TemperatureMaterialandHighTem