45钢电子束相变硬化温度场数值模拟与实验验证

Numerical simulation of temperature field of in electron beam surface hardening process on 45 steel

建立了移动电子束高斯热源作用下的三维相变硬化过程中温度场的数学模型,分析过程中考虑了热源分布、热物性参数、热辐射等因素对温度场的影响,得到了电子束扫描相变硬化温度场的分布规律和硬化层的形态,并进行了实验验证;探讨了电子束工艺参数对硬化区深度和宽度的影响。结果表明:移动电子束高斯热源作用下的温度分布等值线呈勺状,表面最高温度滞后于束流中心,且处理后硬化层横截面呈月牙状;在固态相变条件下,硬化层的宽度和深度随着扫描功率的增加呈非线性增加,随着扫描速度的增加呈非线性减小。

A mathematical model of 3D electron beam phase transformation hardening by moving Gauss distribution heat source was established. The thermal parameters such as heat source distribution, thermal physical parameters and heat radiation were considered. The temperature distribution and morphology of hardened layer in the hardening process were obtained. The effects of electron beam parameters on width and depth of the hardened layer were discussed. The numerical simulation was verified by experimental observation. The results show that the temperature distribution caused by moving Gauss heat source is spoon-shaped, and the highest surface temperature lags behind the beam center. The cross section of the hardened layer is crescent- shaped. In the solid phase conditions, the width and depth of the hardened layer and its maximum hardness nonlinearly increases with electron beam power increasing, and declines with scanning speed increasing.