活塞销的失效大都为疲劳损坏,疲劳裂纹一般均产生在销的内孔表面,呈纵向分布。图1为典型的贝纹状疲劳断口,裂源位于活塞销内端面与连杆小头端面之间。该活塞销渗碳淬硬层约1.3～1.4mm,表层为隐针状回火马氏体和沿晶界分布的少量碳化物和微 Piston pin failure mostly fatigue damage, fatigue cracks are generally produced in the pin bore surface, was longitudinally distributed. Figure 1 shows a typical fatigue fracture with a beige shape. The crack source is located between the inner end face of the piston pin and the end face of the connecting rod. The piston pin carburizing hardened layer is about 1.3 ~ 1.4mm, the surface is hidden needle-like tempered martensite and a small amount of carbide and micro