Analysis of Impact Fatigue Behavior on High Strength Martensitic Stainless Steel
With the frequent occurrence of drill string failures,researchers have been focusing on the mechanism of drill string failure-frac-ture behavior under service conditions.Drill strings are undertaken complex loads during service,including both static loads and high-ener-gy single impact loads,as well as low-energy multiple impact loads,which results in material impact fatigue.Therefore,impact fatigue fail-ure behavior of a novel high-strength martensitic stainless steel under different impact energies was investigated.The results indicate that the primary factor influencing the impact fatigue life of the material is the applied impact energy.The higher the impact energy,the lower the impact fatigue life of the material,however the variation of impact energy may not change the fracture mode of the material.During the initi-ation stage of fatigue crack,an increase of impact energy can lead to rapid crack initiation.Within the propagation stage,impact loads can act on the crack tip and lead to extending gradually for the crack.Finally,a functional relationship between crack length(a)and the num-ber of cycles(N)was established,by which the crack propagation rate was calculated.
high strength martensitic stainless steeldynamic tensile testhigh strain rateimpact fatigueParis Formula
万方数据
维普
