介绍了应用淬透性曲线计算钢的临界直径的方法, 包括淬透性曲线斜率的计算、最小斜率的确定、由最小斜率的端距计算理想直径, 以及由理想直径计算临界直径。拟合了理想直径与50%马氏体端距的方程, 和淬水、淬油临界直径与理想直径的方程, 并列举了40CrH钢、45H钢、42CrMoH钢、20CrMnTiH钢、20CrMnMoH钢及40MnBH钢6种材料临界直径的计算及结果。

The methods that hardenability curves were used to calculate the critical diameter of steels were introduced, including the hardenability curve slope calculation, minimum slope determination, the ideal diameter calculation by Jominy distance on the point of minimum slope, and the critical diameter calculation by the ideal diameter. The equation of the ideal diameter and Jominy distance for 50% martensite was fitted, and the equation of water-quenching and oil-quenching critical diameter and the ideal diameter was fitted. The critical diameter calculations and results of six kinds of material (40CrH steel, 45H steel, 42CrMoH steel, 20CrMnTiH steel, 20CrMnMoH steel, 40MnBH steel) were listed.