Hot rolling of titanium alloy materials should generally be carried out in the B or a+P phase region. The hot rolling temperature is 50~100℃ higher than the forging temperature line, and the plate with a thickness of 2~5mm can use the warm rolling process, and the thinner plate can be cold rolled. During cold rolling, the cold rolling deformation between two anneals is 15% to 60%. Grade 7 Titanium Sheet are metals with phase transformation. The selection of slab heating temperature must consider the process plasticity, deformation resistance of the a+β phase region and the effect of the getter layer on the surface plasticity of the rolled piece at high temperature. The process plasticity of the B-phase region is better than that of the a-phase region, and the deformation resistance is lower, but the heating temperature is high, which increases the depth of the getter layer, and serious cracks will occur on the surface during uneven deformation.
The hot rolling of the titanium plate is carried out in the phase zone, which can ensure good process plasticity, and the total processing rate of the billet can reach 90%. Pure titanium TA1, TA2 and TA3 are below the phase transition point, generally heated at 850~870℃, while TC4 should be selected at the upper limit of the a+B phase transition point or by superplastic forming process (heated at 1000~950℃). TC1, TC2, TC3, etc., the hot rolling process plasticity is slightly worse, the thicker the slab, the more serious the edge cracking and the more serious surface cracking due to uneven deformation during rolling. Although Grade 9 Ti-3Al-2.5V Titanium Plate has good oxidation resistance, it has a high degree of alloying and high deformation resistance. Therefore, selecting the heating temperature of TA7 thick slab in the B phase region is more conducive to deformation, which can make full use of the plasticity of the alloy and reduce the number of tempering.
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