一引言应用光学显微镜对金属断口进行直接观察分析的方法,往往由于断口表面不平坦,加之光学显微镜的焦深短而受到限制。五十年代以来,这一分析方法逐渐由分辨率高、焦深长的电子显微镜所代替。其中,扫描电镜又以其突出的优点在断口分析中应用日趋广泛。但就我国目前状况而言,由于一般工厂缺少这种先进设备,使断口分析工作仍停留在肉眼或低倍观察分析阶段。沈阳风动工具厂在采用T10V制造凿岩机活塞的试验研究中,笔者发现在矿山实际使用中断裂的凿岩机T10V活塞,多数都具有以下共同特点:1.正断、断口平坦;2.属于疲劳断裂;3.宏观断口由浅色平滑的弧形条带(简称平滑区)和深色粗糙的弧形条带(简 I. INTRODUCTION The method of direct observation and analysis of the metal fracture using optical microscope is often limited by the uneven surface of the fracture and the short focal length of the optical microscope. Since the 1950s, this method of analysis has gradually been replaced by high-resolution, deep-focus electron microscopes. Among them, the scanning electron microscope with its outstanding advantages in the fracture analysis is widely used. However, as far as the current situation in our country is concerned, due to the lack of such advanced equipment in general factories, the fracture analysis remains at the naked eye or low magnification stage of observation and analysis. In the experimental study of using T10V to manufacture rock drill pistons, the author found that most of the T10V pistons of the rock drill broken in actual use of the mines have the following common features: 1. Normal breaking and flat fracture; 2. Fatigue fracture; 3. Macroscopic fracture consists of light-colored smooth curved strip (referred to as the smooth area) and dark rough curved strip (Jane