The residual stress and its influence on the fatigue strength induced by explosive autofrettage

With two different explosion methods, different super-high pressure components were autofrettaged, one is the dynamic liquid explosion, the other is sticking oily explosion. The super-high pressure component includes thick wall circles with a crack or notch on the inner wall, super-high pressure thick wall cylinders and fours-ways were chosen to conduct autofrettage. The residual stress was measured, and then the fatigue test was carried out. The test results show that the fatigue initiation life Ni can be increased by 5 times, the fatigue progress life Nf can be increased by 8~10 times in the high cycle fatigue period. In the low cycle plastic fatigue period, the fatigue progress life Nf can also be increased by 1 time. The sticking oily explosion is better than the dynamic liquid explosion because of the increasing of the rigidity of the surface.