Abstract:The effects of unidirectional and reversal hot rolling on the microstructure and mechanical properties of TC4 titanium alloy ingot melted by electron beam cold bed furnace were studied. The results show that the microstructure of TC4 titanium alloy slab is Widmannstatten structure. After hot rolling plastic deformation, the grain boundary is fully broken, and the α phase bundle is twisted, deformed and broken, and it is criss-crossed and distributed in a basket shape. With the increase of the number of reversing hot rolling, the lath-like α phase cross-section is more obvious, which reduces the anisotropy in the rolling direction and the transverse direction, and the comprehensive performance of the reversing secondary hot-rolled sheet is optimal. The fracture transformation forms of TC4 titanium alloy are unidirectional hot-rolled RD ductile fracture, TD ductile + quasi-cleavage mixed fracture reversed one-time hot-rolled RD ductile + brittle mixed fracture, TD ductile + quasi-cleavage mixed fracture reversed two-time hot-rolled ductile fracture. The hot-rolled sheet is mainly a matrix phase of α-Ti and β-Ti. The grain orientation of the unidirectional hot-rolled sheet has a preferred orientation in the <0001> direction; the grain orientation of the reversing once hot-rolled sheet is mainly between <0001> and<"1" ?21 ?0>crystal orientation; the grain orientation of the sheet moves toward <01"1" ?0>, and its grain orientation is between <0001> and <01"1" ?0>. Key words: Electron beam cold bed furnace; TC4 titanium alloy; reversing hot rolling; microstructure; mechanical properties