碳钢热喷涂镍沉积凝固过程热力耦合场的数值模拟及温度应力场的分布规律

Numerical Simulation of Thermo-Mechanical Coupled Field and Distribution Law of Temperature Field in Solidification Process of Thermally Sprayed Nickel Coating on Carbon Steel

为了进一步弄清热喷涂残余应力产生的机理、预测与控制技术,以碳钢表面热喷涂镍为例,对镍沉积凝固冷却过程进行了合理的假设和简化。利用ANSYS平台,采用热力耦合计算,模拟了涂层冷却过程,获得了温度场和应力场分布规律,分析了涂层上某些特征点的温度和应力随时间变化的情况,并探讨了基体预热温度和涂层厚度对涂层/基体界面应力的影响。结果表明,涂层温度沿中心向边缘逐渐降低,随时间延长呈降低趋势;基体温度随时间的变化呈先增加后降低趋势;涂层主要承受残余压应力作用,随基体温度升高,残余应力呈减小趋势,随涂层厚度增加,残余应力呈增大趋势。

With thermal spraying of Ni coating on carbon steel substrate as an example,the deposition-solidification-cooling process of the Ni coating was reasonably simplified under some assumptions.The cooling process of the coating was simulated with software of ANSYS based on thermo-mechanical coupling calculation,and relevant distributions of the temperature field and stress field were obtained.Moreover,the changes of the temperature and stress at some characteristic locations of the coating with time were analyzed,and the effects of pre-heating temperature of the substrate and the thickness of the coating on the stress at coating-substrate interface were investigated.It was found that the temperature of the coating gradually declined from the central zone to the edges and also declined with extending time.The temperature of the substrate rose initially but declined later.Besides,Ni coating was dominated by residual compressive stress which gradually declined with increasing substrate temperature but rose with increasing coating thickness.