齿轮用钢电子束表面硬化工艺的数值模拟

Numerical simulation of electron beam hardening of steel for gears

针对齿轮用钢35Ni4Cr2MoA的电子束局部硬化工艺,建立了移动电子束局部加热的有限元分析模型和连续加热冷却过程奥氏体化相变计算模型,采用Visual FORTRAN语言自行编制了奥氏体转变模拟程序,成功地模拟了电子束局部硬化的热过程和组织变化。对不同硬化工艺条件下奥氏体化程度分布和硬化层轮廓的模拟预测表明,随着电子束移动速度的提高,奥氏体化开始的温度升高,奥氏体化程度显著降低,奥氏体化的范围(硬化层的宽度和深度)明显缩小。在确保试件中心所经历的最高温度低于材料熔点并且大致相当的前提下,随电子束移动速度降低,硬化所需热输入增加。

The finite element model of local heating by a moving electron beam and the phase transformation model of austenization during continuous heating and cooling were built for electron beam hardening of 35Ni4Cr2 MoA steel for gear.The program for the modeling of austenization was developed using Visual FORTRAN language and simulate the thermal and phase transfonnation evolution successfully.The simulation results of the distribution of austenization degree and the contour of hardened layer for different parameters showed that the austenization temperature increases,the degree of austenization decreases remarkably and the extent of austenitized region narrows obviously with the increase of the moving speed of electron beam.The heat input required for hardening increases with the decrease in the moving speed of electron beam on condition that the maximum temperatures of the central location in the test piece for different parameters are well below the fusion point and equal to each other approximately.