The expansion bolt

The bearing capacity of expansion bolts is lower than chemical-fixing bolt, but it is economical.

膨胀螺栓与化学螺栓和化学植根螺栓强度虽然较低，但其经济性非常好。

It is concluded that, the residual stress induced by cold expansion can maintain enough strength to prevent and retard fatigue crack initiation and growth in rail bolt hole.

结果表明，冷扩张过程所引入的切向残余压应力能保持足够的强度，以对钢轨螺栓孔起到显著的防裂和止裂作用。

By comparing with the experimental results, a detailed discussion on the influence of cold expansion on the fatigue performance of rail bolt hole was presented.

结合实验探讨了冷扩张过程对钢轨螺栓孔疲劳寿命的影响方式和效果。