闸板表面激光熔覆应力场数值模拟

Numerical Simulation of Stress Field in Laser Cladded Gate of Flat Gate Valve

闸板作为平板闸阀的关键件,闸板的擦伤和腐蚀严重妨碍了平板闸阀在石油行业中的应用。鉴于此,利用SYSWELD有限元分析软件,以热弹塑性理论为基础,采用修正高斯热源模型,对平板闸阀易损件闸板表面激光熔覆Ni基合金过程进行了数值模拟,对激光熔覆温度场和应力场进行了分析,得到了闸板表面激光熔覆残余应力的分布规律。模拟结果表明,激光熔覆过程中升温速率要明显高于冷却速率;闸板熔覆层中,残余应力随着z轴负方向呈增大趋势,越靠近闸板中圆孔处拉应力越大,越易产生裂纹;在熔覆层厚度方向上,残余应力峰值出现在距表层0.53 mm处。研究结果可为平板闸阀的设计和现场使用提供参考。

As a key member of gate valve, the abrasion and corrosion of the gate can severely hamper the ap-plication of flat gate valve in the oil industry. Based on thermal elastoplastic theory, laser cladding of the gate with Ni-based alloy was simulated by means of SYSWELD software and modified Gauss heat source model. Residual stress distributions were obtained by analyzing temperature field and stress field of the gate. The analysis results show that heating rate is far faster than cooling rate in laser cladding of the gate; the residual stress in clad of the gate gradually increases along the contrary direction of z-axis, and tensile stress increases near the hole of the gate where crack always occurs; in the direction of y-axis, the peak of the residual stress occurs in the area far from surface 0. 53 mm. The results can provide a reference for the design and field use of flat gate valve.