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本文推导出渗碳和碳氮共渗气氛的模型,它可以预测与气氛呈平衡状态的薄片试样碳、氮含量;碳势、氮势以及碳、氮活度。这个模型认为在渗碳和碳氮共渗气氛中所发生的重要反应是同时进行的,每个反应有各自的活度值和反应速率。其次,这个模型为预测给定热处理周期后的扩散曲线提供基础。表面碳氮含量非恒值,其变化量取决于各自组元的净反应速率,碳氮扩散系数与浓度有关,采用数学上的有限差分近似法来求解微分方程式。对碳势、氮势及钢中表层碳氮分布曲线来说,实验数据与预测值取得了令人鼓舞的一致。
In this paper, a model of carburizing and carbonitriding atmosphere is deduced, which can predict the carbon and nitrogen content, carbon potential, nitrogen potential and carbon and nitrogen activity of the flake samples in equilibrium with the atmosphere. This model assumes that the important reactions that take place in the carburizing and carbonitriding atmospheres occur simultaneously, with each activity having its own activity value and reaction rate. Second, the model provides a basis for predicting the diffusion curve after a given heat treatment cycle. Surface carbon and nitrogen content is not constant, the amount of change depends on the net reaction rate of each component, carbon and nitrogen diffusion coefficient and concentration, the use of mathematical finite difference approximation to solve the differential equation. For the carbon potential, nitrogen potential and surface C and N distribution curves in steel, the experimental data and the predicted values have made encouraging consensus.