40Cr钢强韧化的新探索

对４０Ｃｒ钢高、低温淬火强韧化进行了评价；提出强韧化的新途径──复合热处理强韧化，并按 此设计了几种新工艺．性能试验结果表明：新工艺使４０Ｃｒ获得较好的强韧化，即在保持强度水平 下，塑性、韧性、系列冲击韧性及冷脆转变温度，和疲劳性能均得到明显的改善．用金相方法及 扫描电镜观察分析指出，这与微区成分均匀、晶界净化、组织细化与改善，从而避免或减少了沿 晶或解理脆断有关．

A NEW EXPLORATION INTO THE STRENGTHENING AND TONGHENING OF 40Cr STEEL

The strengthening and toughening by high and low temperature quenchi- ng have been commented. A new way of strengthening and toughening, i.e the compound heat treatment, was advanced, and the new processes were de -signed accordingly. The result of experiment in property showed that better strengthening and toughness, for-40Cr was acquired by the new processes, which is to say, the ductility, toughness, transition temperature, and the fatigne behaviour were all improved obviously without loss in strength. By using the metallographic method and the SEM observation, it was revealed that these are related to the composition homogenization in microregion, purification in grain boundaries, structure fining and improving, and avoi -dance of the intergranular or cleavage brittle fracture.