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本文从理论和实验两方面,对20钢电子束相变硬化处理表面的热传导问题进行了研究.建立了移动半无限大工件、表面受均匀矩形热源加热的稳态、三维热传导模型.用有限差分方法数值求解了工件表面的温度场.由此估算了不同工艺参数处理对的表面最高温度、加热和冷却速度等一些无法实测的数据.基于材料热物性参数为常数的假设,得出了工艺参数与表面熔化温度之间的关系.此关系可作为电子束相变硬化处理时恰当选择工艺参数的依据.在实验方面,通过改变功率、移动速度和束斑尺寸等工艺参数,研究了20钢表面处理层的显微组织、相变区的形状和深度,确定了表面熔化的开始.实验结果与计算值两者符合较好.从而证明此计算模型是有效的.
In this paper, the heat conduction problems of the 20 steel electron beam transformation hardening process are studied both theoretically and experimentally.The steady and three-dimensional heat conduction model is established for the moving semi-infinite workpiece and the surface is heated by a uniform rectangular heat source.The finite difference Methods The temperature field of the workpiece surface was numerically solved, and some unobservable data such as the maximum surface temperature, the heating rate and the cooling rate of the different process parameters were estimated.Based on the assumption that the thermal physical property parameter was constant, the process parameters And the relationship between the surface melting temperature.The relationship can be used as the basis for proper selection of the process parameters during the electron beam transformation hardening process.In the experiment, by changing the power, moving speed and beam spot size and other process parameters, studied the 20 steel surface treatment The microstructure of the layer and the shape and depth of the phase change zone, the onset of surface melting is confirmed.The experimental results and the calculated values agree well with each other, which proves that this model is effective.