METHOD FOR PRODUCTION OF SEMI-FINISHED PRODUCTS WITH FINE CRYSTALLINE GLOBULAR STRUCTURE IN ALFA + BETA TITANIUM ALLOYS Russian patent published in 1998 - IPC

FIELD: metallurgy. SUBSTANCE: method includes preliminary heat treatment of blanks in beta region and saturated with hydrogen up to concentration of C (wt.%) on the basis of condition C <, where k is empirical coefficient assuming values of 3.5-4.5 depending on alloying system; To is temperature of polymorphic (alpha-beta) conversion of alloy up to its saturation with hydrogen; Td is deformation temperature, and reduction degree of not less than 70% at temperature below the temperature of (alpha-beta) conversion. Blanks may be saturated with hydrogen at temperature below the temperature of preliminary heat treatment from gas phase. Preliminary heat treatment is carried out at temperature (Kelvin scale) T = 0.96 To exp(-0.23 C) + (20-50). Deformation of alloy BT9 is carried out at 798-1-73 K. After deformation, hydrogen, if needed, is removed by vacuum annealing at temperature of not in excess of deformation temperature. EFFECT: provision of production of semifinished products with sizes of grains up to several dozens of nm, smaller than in the known methods. 5 cl, 1 tbl