摘要
观察并研究了Co基合金熔覆过程的温度场和应力场的规律,建立了激光熔覆预置Co基合金粉末过程的三维模型,考虑温度变化对热物理参数的影响以及表面对流换热和辐射散热等影响因素,使用SYSWELD软件分析了激光熔覆过程中的温度场和应力场,并进行了实验验证。结果表明:温度场等温线呈椭圆形,熔池最高温度区域滞后于光斑中心,扫描速度为4 mm/s的激光熔覆过程获得了良好的冶金结合;基体预热温度从20℃增加到300℃,t8/5从0.5 s增加到1.5 s,熔池的瞬时冷却速度分别减小至0.88倍和0.64倍,工件的残余应力和变形均明显减小,这说明对基体适当预热能有效降低熔覆层的开裂倾向。模拟结果为激光熔覆过程的优化提供了理论依据。
The rule of temperature field and stress field during laser cladding with preset Co based alloy powder were observed and studied,a three-dimensional(3D) physical model of laser cladding has been made and the thermo-physical properties established as the functions of temperature with consideration of boundary condition,non-linear units and so on.The temperature field and stress field of laser cladding process were analyzed by SYSWELD software.A 5 kW CO 2 laser was used to preset Co-based alloy coatings on low carbon steel substrate.The results showed that the isotherms of temperature field were ellipse and the high temperature of molten cool was little behind the centre of laser spot.Favorable metallurgy bonding was obtained by scanning velocity was 4 mm / s.When preheating temperature of substrate was increased from 20 ℃ to 300 ℃,t 8 /5 was increased from 0.5 s to 1.5 s,and instantaneous cooling rate of molten pool was decreased to 0.88 times and 0.64 times,the residual distortion and stress of work-piece were all obviously decreased.This showed that cracking was effectively reduced by the proper preheating.The simulated result provided the theoretical reliance for the optimization of the laser cladding.
出处
《南阳理工学院学报》
2013年第3期95-100,共6页
Journal of Nanyang Institute of Technology
基金
安徽省高校省级自然科学基金项目(KJ2012B031)
