一、问题的提出我们在使用摆锤式冲击试验机作冲击试验时,发现对塑性不很好、冲击韧性不高的某些钢材,有时可听到卡锤响声,并在断后试样的两条对角侧棱的对应位置上各产生一个较深的被钳口卡的凹痕(图1a)和一个较长的被摆刀卡的凹痕(如图1b)。这种可听到响声的卡锤现象,可使冲击韧性值明显增大。例如在含碳量为0.60～0.70的轮箍钢的156个冲击试样中,就有12个试样发生了这种卡锤现象。占总试样数的 First, the question put forward We use the pendulum impact test machine for impact test, found that the plastic is not very good, the impact toughness of some of the steel, and sometimes can hear the hammer sound, and after the sample of the two The corresponding positions of the diagonal side edges produce a deeper notch of the jaws to be chucked (FIG. 1a) and a longer notch of the swaged card (FIG. 1b). This audible click hammer phenomenon, can make the impact toughness value increased significantly. For example, out of 156 impact specimens of wheel steel with a carbon content of 0.60 to 0.70, 12 specimens were subjected to this phenomenon. The total number of samples