电子束预热底板表面温度的测量及数值模拟

针对电子束选区熔化成形技术中存在的真空辐射环境及表面不允许破坏的情况,提出热电偶测温和数值模拟相结合测温的方法对经电子束预热处理的底板表面温度进行测量.热电偶测温为数值模拟中电子束热效率、电子束作用深度和底板厚度三个因素的水平进行优化,从而得到合理的数值模拟程序,并利用该数值模拟程序和优化的因素水平对底板表面温度进行合理的预报.结果表明,采用数值模拟及热电偶底面测温相结合可以得到精确度较高的表面温度,底板表面温度达到钛合金粉末烧结温度800℃时的电子束预热时间为1 600 s.

Measurement and simulation of surface-temperature field of plate preheated by electron beam

The vacuum environmental radiation is very severe and the surface of plate can not be destructed for electron beam selective melting forming,so the method combined thermcouple measurement and numerical simulation was used to obtain temperature field of plate’s surface under electron beam preheating.Measurement results of thermocouple were utilized to optimize the heat efficiency,depth of electron and thickness of plate,consequently get reasonable simulation program.Temperature of plate’s surface was forecasted by simulation program and optimized factor level.Results showed that the higher accuracy of surface temperature could be obtained by the numerical simulation combined with temperature measurement by thermal couple.When temperature of plate’ surface reached 800 ℃ which is as same as sintering temperature of titanium alloy powder,preheatingtime of electron beam was 1 600 s.