METHOD FOR MANUFACTURING OF SEMI-FINISHED SHEET PRODUCT FROM TITANIUM ALLOY Russian patent published in 2008 - IPC C22F1/18 

FIELD: manufacture of semi-finished sheet product from low-plasticity two-phase titanium alloy of submicrocrystalline structure suitable for low-temperature superplastic deformation.

SUBSTANCE: method involves rolling blank with prepared structure at temperature below polymorphic transformation temperature under isothermal or quasi-isothermal conditions provided by heating of rolls. Grain size stabilization and isotropic properties are reached thanks to the fact that rolling process is provided in low-temperature superplastic deformation mode: at first passage deformation is carried out at the extent of ε≥ε_min, where ε_min is minimum extent at which structural state of alloy is formed in selected temperature-rolling speed mode. Such structural state is necessary for enabling of cooperated grain boundary sliding during deformation. After each subsequent passage of rolling step, blank is cooled for fixing of structural state provided upon deformation. During heating of blank in furnace for subsequent passage of rolling step, heating time is limited in order to avoid disturbance of structural state of alloy produced at previous rolling passage.

EFFECT: increased efficiency and improved quality of semi-finished sheet product fit for further low-temperature superplastic deformation.

12 cl, 9 dwg, 1 tbl, 7 ex