自行车中轴棍在交变应力作用下,除了承受扭转载荷和滚动摩擦磨损外,还承受较大的弯曲和一定量的冲击载荷。因此,中轴棍应具有良好的疲劳强度和较高的疲劳寿命。但在生产和使用过程中,中轴棍的断裂仍时宵发生。为此,我们从断裂的中轴棍中选取典型试样,进行失效分析,提出改进措施,解决了中轴棍断裂问题。一中轴棍用材、生产工艺及热处理规程 1.中轴棍的用材中轴棍由20钢制造而成,其化学成分列于表1。 2.生产工艺冷挤压成形(见图1)→气体渗碳(930±10℃×4h)→淬火加热(830±10℃×5min)→ Under the action of alternating stress, the bicycle axle is subject to large bending and a certain amount of impact load in addition to torsional load and rolling friction and wear. Therefore, the axis of the stick should have good fatigue strength and high fatigue life. However, in the production and use of the process, the axis of the broken stick is still midnight. For this reason, we select the typical sample from the broken middle shaft sticks, carry on the failure analysis, put forward the improvement measure, solved the middle shaft stick fracture problem. A shaft material, the production process and heat treatment procedures 1 axis shaft material sticks made of 20 steel shaft, the chemical composition in Table 1. 2. Production process cold extrusion (see Figure 1) → gas carburizing (930 ± 10 ℃ × 4h) → quenching (830 ± 10 ℃ × 5min) →