Abstract: TC4 alloy slab ingot was used as a direct-rolled billet in the EB furnace at one time. A low cost TC4 alloy wide plate with a size of 46 mm×2650 mm×8700 mm was successfully prepared on a 4200 mm wide and thick plate mill, the effect of annealing temperature on the microstructure and mechanical properties of the low cost TC4 alloy plate was studied. The results show that the EB smelted TC4 alloy slab is subjected to dual reversing rolling, and the coarse as-cast microstructure is broken. The microstructure of the hot-rolled TC4 alloy plate has a high content of equiaxed α-phase or strip α-phase, small transverse and longitudinal room temperature tensile properties differences, and the transverse room temperature impact absorbed energy is less than the longitudinal direction, and the strength of the core part is higher than the surface layer. When annealed at 750-900 ℃, the transverse and longitudinal section of the TC4 alloy sheet are equiaxed structure, when annealed at 950 ℃, the transverse and longitudinal section are dual-state structure, when over 980 ℃, the cross-section is dual-state structure, and the longitudinal section is widmanstatten structure. As the annealing temperature increases, the tensile strength and the proof strength plastic extension of TC4 alloy sheet show a downward trend, and the elongation is basically unchanged. The impact absorbed energy at room temperature first increases and then decreases. After annealing at 900 ℃, the strength, elongation and impact absorbed energy achieve the best match.

Key words: TC4 titanium alloy, annealing temperature, low cost, wide and thick plate, microstructure, mechanical properties