用非表面强化方法提高铸态球铁曲轴的可靠性

在不采用圆角滚压等表面强化处理的条件下，为使铸态球铁曲轴的弯曲疲劳强度和耐磨性达到技术要求，采取了三个措施：（1）通过合金化和优化铸造工艺，使强度和韧性达到最佳匹配；（2）加大连杆轴颈与曲柄臂的过度圆角；（3）增大曲柄臂的厚度，曲轴弯曲疲劳弯曲强度对比试验和300h台架可靠性试验以及25000km道路试验均证明，采用上述措施制造铸态球铁曲轴的方案既降低曲轴成本，又能使曲轴具有足够的弯曲疲劳强度。

An Experiment on Using Non-Surface-Strengthening Method to Increase Reliability of As-Cast Nodular Iron Crankshaft

Without using surface-strengthening treatments such as round corner rolling,three measures was adopted to make the bending fatigue strength and wear resistance of the nodular iron crankshaft to meet their thechnical requirements:(1)obtain the optimum match of strength and toughness by alloying and optimizing foundry processes;(2)enlarge the round corners between the conrod shaft necks and the crank arms ;(3)increase thickness of the crank arms.The comparative bendintg fatigue test,300hrs bench running reliability test and25000km driving reliability test have showed that adopting above mentioned measures to produce as-cast nodular iron crankshaft is a practical scheme which not only reduced production cost,also made the crankshaft to be of sufficient bending fatigue strength.