METHOD FOR PRODUCING TITANIUM ALLOY BILLETS FOR PRODUCTS EXPERIENCING VARIABLE MECHANICAL LOADS Russian patent published in 2018 - IPC C22F1/18 B21J5/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, namely, to producing (α+β)-titanium alloy billet for products experiencing varying mechanical loads, and can be used for the manufacture of products having high energy intensity. Method for producing (α+β)-titanium alloy billet for products experiencing varying mechanical loads, includes multi-stage forging billet. In the first and third stages of forging, the titanium alloy billet is heated to a temperature T₁, which is higher than the temperature of complete polymorphic transformation T_β+40≤T₁≤T_β+130, where T_β – temperature alpha-beta phase transition. In a second step, titanium alloy billet is heated to a temperature T₂, which is lower than the polymorphic transformation T_β-60≤T₂≤T_β. At all stages, forging is carried out with a deformation of 1.1–1.5 for 10–20 minutes when the billet rotates about its axis according to a scheme including one complete rotation of the billet with a rotation of 90°, the second full turn with a turn of a billet through 45°, the third full turn with the turn of the billet through 22°. After each stage, the billet is quenched or cooled in water. In this case, after the third stage, all subsequent steps of forging are carried out when the billet is heated to a temperature T_β-60≤T₂≤T_β and with a deformation of 1.1–1.6 for 10–20 minutes when the billet rotates about its axis by 90°. Forging steps conducted after the third stage are repeated until a uniform, finely dispersed microstructure with a grain size (0.5–5.0) mcm containing equiaxed α-phase in an amount of 40–80 % in the transformed β-matrix without the formation of a continuous grid α-phase at the boundaries β grains, then the resulting billet is annealed at a temperature of (830–870) °C for 40–80 minutes and cool.

EFFECT: produced billets have high strength and yield strength values.

1 cl, 3 tbl