Results of mechanical strength and fatigue tests are presented for flat specimens of titanium alloys OT4-1 and VT-20 in air and in 3 percent aqueous sea salt solution, and for cylindrical weld specimens made of technical-grade VT1-OS alloy in Ringer-Locke solution. It was shown that the influence of preliminary strain of the durability of titanium alloys depends on the initial condition of the material, the strain rate, the load application conditions, and the medium in which cyclical stress occurs. Preliminary strain by upset forging generally has much greater influence when done in a hammer vs. a press. Relationships were obtained for static and cyclical mechanical strength characteristics vs. mechanical inhomogeneity and grain size of the heat-affected zone of titanium welds. Recommendations are given for estimating fatigue characteristics based on type of mechanical inhomogeneity and on structural condition.
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