Preparation method for titanium alloy plate blank

The invention discloses a preparation method for a titanium alloy plate blank. The method comprises the following steps: providing a titanium alloy cast ingot and a vacuum consumable electro-arc furnace, and smelting the titanium alloy cast ingot in the vacuum consumable electro-arc furnace; forming a cast ingot to be subjected to cogging, a primary forging blank and a to-be-forged forging blank in sequence, heating the to-be-forged forging blank below a beta-phase transformation point, rotating the to-be-forged forging blank along an axial plane by 90 degrees and then forming a to-be-forged plate blank by carrying out transverse extension deformation forging on a quick forging press; and heating the to-be-forged plate blank below the beta-phase transformation point, rotating the to-be-forged plate blank along the axial plane by 90 degrees and then forming a finished product plat blank by carrying out longitudinal extension deformation forging on the quick forging press. Compared with a small-specification plate blank produced by a conventional small-specification plate blank forging technology, a large-specification high-performance titanium alloy plate blank produced by the method disclosed by the invention is greatly improved in unit weight and width, good in structural homogeneity and capable of meeting rolling requirements of a high-performance thick plate.