Forecasting VT6 Titanium Alloy Rolled Bar Mechanical Properties

Abstract

Statistical studies of the chemical composition (alloying element and impurity contents, aluminum and molybdenum equivalents), polymorphic transformation temperature, structure (globular, lamellar, transition, mixed, basket-weave), and standard mechanical properties (tensile strength, elongation, reduction of area, impact strength, hardness) of rolled bars 15–150 mm in diameter, prepared from titanium alloy VT6 in 2013–2017 are performed. Various types of structure are obtained by changing deformation regime and simple annealing (600–920°С, 20–180 min, air cooling). Correlation relationships of mechanical properties with various factors are analyzed. It is established that the mechanical properties of bars with globular, transitional, and mixed structures are more dependent on fluctuations in grade composition and annealing regime than on the type of structure. Multivariant regression dependences are proposed for evaluating mechanical properties from alloying element and impurity equivalents for aluminum and molybdenum, the difference between polymorphic transformation and annealing temperatures, annealing time, and bar diameter.