Increasing the Stability of Mechanical Properties of Semifinished Products from Ti–6Al–4V Alloys by Correcting the Alloying Range and Annealing Modes

Statistical studies on the stability of the mechanical properties of various semifinished products made from Ti–6Al–4V alloys depending on the content of alloying elements and impurities after annealing under factory conditions have been conducted. Results show that the influence of each alloying element and impurity may be insignificant, but their combined effect in terms of aluminum and molybdenum equivalents leads to a significant variation in properties. The influence of the chemical composition in terms of aluminum and molybdenum equivalents, as well as simple annealing modes, the difference between the polymorphic transformation temperature and annealing temperature, and the diameter of rolled rods of 15–150 mm on the mechanical properties of the titanium alloy VT6 has also been examined. Based on the probabilistic approach, recommendations have been provided to improve the stability of the properties of VT6 alloy rolled rods and eliminate defective products by adjusting the annealing modes depending on the content of alloying elements and impurities.