The reasons why surface of workpiece is moistened from bottom to top in quenching and axial hardness gradient is generated after quenching are also given in this paper.

• 对试验中所观察到的工件表面由底部向顶部逐渐润湿的现象，以及淬火后工件产生轴向硬度梯度的原因进行了解释。