提出了一种以计算若干相关的相变关键点来有效预测和建立中碳合金钢等温相图的新思想，实验结果表明，该方法不仅可以通过精确计算 Ｂ Ｓ 温度从而准确预测两条 ｃ 曲线间的峰谷位置， 而且在预测较多元、以及在较大的合金含量范围内预测中碳合金钢的等温相图上有较大优势， 同时， 该思想对设计新的多元合金钢提供了十分有效的预测手段。 A new idea is proposed to effectively predict and establish the isothermal phase diagram of medium carbon alloy steels by calculating a number of related phase transformation key points. The experimental results show that this method not only can accurately predict the B c temperature, Between the peak and valley positions, but also in the prediction of more multivariate, and in the context of large alloy content prediction of carbon steel isothermal phase diagram has a greater advantage, at the same time, the idea of ​​the design of a new multi-alloy steel provides a very Effective means of forecasting.