Many studies have been done on the workability of titanium alloys because these alloys are inferior in machinability and hot workability when compared with other structural materials, such as steel and aluminum alloys. KS EL-F(Ti-4.5Al-4Cr-0.5Fe-0.15C)has been developed with mechanical properties equivalent to those of Ti-6Al-4V at room temperature and excellent hot workability. This study found that increasing Fe and decreasing the Cr concentration in the composition of KS EL-F improved both machinability and hot workability. It was found that with the modified alloys, there was a decrease in tool tip wear of almost 30% (Cr:1-2.5%, Fe:1.25-2%),and the hot deformation stress was reduced by about 10%. Furthermore, decreasing Cr suppressed aging embrittlement caused by the precipitation of TiCr₂. KS EL-F 531C has been developed newly with more excellent workability, which is suitable for the application of airplane parts.