我单位购入北京建筑机械厂产的一台起重机,使用14个月后回转减速机小齿轮轴突然断裂。断口位于轴端花键根部,见图1。 断轴时环境温度为-24℃,润滑脂为ZG—2。回转减速机两个,回转小齿轮轴直径尺寸不相等,断裂的为70毫米,未断裂的为80毫米。 轴的材料为40Cr(测得),26个花键齿,花键长度为55毫米,加工后淬火处理。 断口不齐,断面呈凸凹型,粗糙不平,灰白色;每个花键齿根部向轴中心有纵向裂纹;距花键末端25毫米处有扭转变形及横向断裂纹,26个花键齿几乎全部横 My unit buys a crane produced by Beijing Construction Machinery Factory and suddenly breaks the pinion shaft of the revolving reducer after 14 months. Fracture at the shaft end spline root, shown in Figure 1. Broken axis when the ambient temperature is -24 ℃, grease ZG-2. Swing reducer two, rotary pinion shaft diameter sizes are not equal, broken 70 mm, not broken 80 mm. Shaft material is 40Cr (measured), 26 spline teeth, spline length of 55 mm, quenched after processing. Fracture irregularity, the section was convex and concave, rough, gray; each spline tooth root center longitudinal crack; 25 mm away from the end of the spline deformation and transverse rupture, 26 spline teeth almost all horizontal