Corrosion Fatigue Properties of Hot Continuous Rolling Ti-Al-Nb-Zr-Mo Alloy Seamless Tube by Electron Beam Welding in 3.5% NaCl Solution

In this paper, the fatigue properties of electron beam welded joints in newly developed hot continuous rolling titanium seamless tubes in air and corrosive environments are studied. The composition of this titanium alloy material is specifically designed for application in the submarine pipeline domain. The fatigue limit of the titanium alloy welded joint is 168 MPa in a corrosive environment, which is 8% greater than that of TWIP steel, which has good corrosion properties. However, the fatigue limit of the welded joint is 25.6% less than 225 MPa in air. The fatigue fracture mechanisms are unique at different stresses, and the influence of the corrosive environment on the fatigue life at a low stress is greater than that at a high stress. At a low stress, the fatigue life is mainly degraded by the stress concentration caused by the oxide film being destroyed by the corrosive medium. However, the alternating load is the key influencing factor at a high stress.