Titanium Bar Rolling for Aircraft

Heating and hot-rolling characteristics of bars used for die-forged blades and fastener manufacturing. In the former Soviet Union, the bulk material used for aircraft blade manufacturing consisted of titanium alloy bars with diameters ranging from 10 to 60 mm, such as BT3-1, BT8, BT9, and OT4. Aviation fasteners generally used BT16 titanium alloy bars with diameters ranging from 4.0 to 16 mm. Grade 9 Ti-3Al-2.5V Titanium Plate / Grade 9 Titanium Plate / Ultra-Thin Titanium Alloy Sheet

The heating and hot-rolling characteristics of BT3-1, BT8, BT9, and OT4 alloys determine the bar quality requirements. For example, when hot-rolled within the alloy's ot+p phase region, if the deformation is at least 40%-50%, the material exhibits the highest plasticity and fatigue strength. However, rolling at these temperatures significantly increases deformation resistance in the opening and intermediate passes, increasing unit pressure and overloading the rolling mill motor. In this case, the rolling process should be carried out in two stages: (1) pre-rolling at a temperature above the a + p-P transformation temperature; (2) rolling to the finished size at the ot + P phase temperature of the alloy. During the final rolling stage, the rolled material should be cooled to a temperature below 650°F. Bars with a diameter greater than 8.0 mm and the return of bars with a diameter of 4.0-8.0 mm should be rolled in one pass.