Effects of different heating processes on microstructure and properties of TC11(TI-6.5AL-3.5MO-1.5ZR-0.3SI) titanium alloy and titanium rod

TC11(TI-6.5AL-3.5MO-1.5ZR-0.3SI) titanium alloy is a + β type heat resistant titanium alloy, which is mainly used for manufacturing aircraft compressor discs, blades and other parts. It is the main titanium alloy material for domestic aviation engines and has been widely used in the rotating parts of rocket engines. With the wide application of this alloy, the requirements of its technical datum are becoming more and stricter.　　

In the deformation of titanium alloy semi-finished products, especially in the deformation of two phase titanium alloy semi-finished products, alloy composition, the original organization, heating system, deformation rate, deformation uniformity and deformation temperature condition is the basic factors influencing the macrostructure rod end. While the different organizations can greatly change the mechanical properties of the semi-finished products. Researchers with forging and rolling equipment production specification for Φ Φ 29 mm and 73 mm of TC11(TI-6.5AL-3.5MO-1.5ZR-0.3SI) titanium alloy rod, study the influence of different thermal processing on the microstructure and mechanical properties of its.

Experiment selects three times for a company’s vacuum material since the electricity arc smelting ingot, perform similar craft, breakdown, forging provide specifications for 150 mm strip rolling billet and Φ Φ 125 mm fine forging machine forging blank, using the optical microscope magnified 100 times to observe, the rupture were relatively bulky shaft such as organization and uniform.　

The billet in precision forging machine and equipment production specifications for HSM for Φ Φ 29 mm and 73 mm of TC11(TI-6.5AL-3.5MO-1.5ZR-0.3SI) titanium alloy rod, the heating temperature is 970 ℃ and the deformation velocity of 2.5 m/s.

Precision forging technology: one fire times with 4 times deformation are made by using precision forging equipment. Finally, the total deformation of 65.9%, with an average of 13 mm, production Φ 73 mmTC11(TI-6.5AL-3.5MO-1.5ZR-0.3SI) forging of titanium alloy rod. Three fire times and 9 times of deformation are performed by using fine forging equipment. A single fire time average deformation of 61.1%, the average reduction of 8 mm, production Φ 29 mmTC11(Ti-6.5Al-3.5Mo-1.5Zr-0.3Si) forging of titanium alloy rod.　　

Rolling technology: using strip equipment to conduct a fire time 9 times out of shape, the total deformation of 76.3%, with an average of 35 mm, 73 mmTC11(Ti-6.5Al-3.5Mo-1.5Zr-0.3Si) production Φ titanium alloy rolling bar. Two fire times using continuous equipment to 15 a deformation of a single fire time deformation of 80.3% on average, an average reduction of 29 mm, production Φ 29 mmTC11(Ti-6.5Al-3.5Mo-1.5Zr-0.3Si) titanium alloy rolling bar.　　

The samples were annealed at 950℃/1h•AC+530℃/6h•AC, and the microstructure and properties of the finished bar with different processes were tested. The test results show that:

(1) the precision forging process of TC11(TI-6.5AL-3.5MO-1.5ZR-0.3SI) specifications for 73 mm and Φ Φ 29 mm bar finished product, its microstructure organization of the bar is small, and good uniformity than strip craft production.

(2) At the same heating temperature, the mechanical properties of TC11(TI-6.5AL-3.5MO-1.5ZR-0.3SI) titanium alloy bar produced by precision forging process are better than those of rolled bar, which is suitable for the production of blade bar with high requirements on structure and performance. Compared with the precision forging process, the new hot rolling process has higher production efficiency, better flatness and surface quality and can save production of finished products.