METHOD FOR FORGING TITANIUM ALLOY AND FORGED TITANIUM ALLOY MATERIAL

摘要

A method for forging a titanium alloy having a beta-transformation temperature of Tbeta(˚C), which comprises satisfying the relationships of (Tbeta - 400)˚C <= Tm and 400˚C <= Td <= 700˚C, wherein Tm and Td represent the temperature of a material to be forged and the temperature of a mold, respectively, and carrying out the forging of the alloy at a strain rate of 2 X 10<-4>S<-1> to 1 S<-1>, and preferably further satisfying the relationship of Tm - Td <= 250˚C and/or using a titanium alloy having a specific chemical composition. A titanium alloy material having been forged by the above method has a microstructure being fine and controlled so as to have a predetermined structure, and thus exhibits material properties being nearly uniform in the thickness direction thereof, is excellent in ductility and fatigue characteristics, is easy to finish the surface after forging, is less susceptible to cracking, and exhibits excellent formability.