METHOD OF THERMO-MECHANICAL TREATMENT OF TITANIUM ALLOYS Russian patent published in 2003 - IPC

FIELD: non-ferrous metallurgy thermo- mechanical treatment of titanium alloys; aeronautical engineering. SUBSTANCE: proposed method includes repeated heating of titanium alloys to temperature above and below polymorphous transformation temperature and deformation in the course of cooling to temperature below polymorphous transformation temperature , holding at heat and cooling; thermo-mechanical treatment is performed at six stages; at first five stages the following operations are performed: heating to temperature of (T_ptr+120 to T_ptr+270) C, deformation at 50-70% and temperature of termination of deformation of (T_ptr minus 40 to T_ptr minus 100) C; heating to temperature of (T_ptr + 60 to T_ptr + 160) C, deformation at 40-60% and temperature of termination of deformation of (T_ptr minus100 to T_ptr minus 180) C; heating to temperature of (T_ptr minus 20 to T_ptr minus 40) C, deformation at 10-30% and temperature of termination of deformation of (T_ptr minus 140 to T_ptr minus 160); heating to temperature of (T_ptr +20 to T_ptr +50) C, deformation at 40-60% and temperature of termination of deformation of (T_ptr minus 110 to T_ptr minus 130) C; heating to temperature of (T_ptr +20 to T_ptr +50) C, deformation at 30-70% and temperature of termination of deformation of (T_ptr minus 110 to T_ptr minus 130) C; at sixth stage, heating to temperature of (T_ptr minus 400 to T_ptr minus 500) C is performed at holding at heat continued for 5-20 h, where T_ptr is polymorphous transformation temperature. Proposed method ensures increase of yield point by 15-25%; increase of crack resistance by 25-30% ; reduction of mass by 15-25%. EFFECT: increased payload of flying vehicle; enhanced operational reliability. 1 tbl, 3 ex