Processing method for TC4 titanium alloy large-sized bar

Abstract

The invention discloses a processing method for a TC4 titanium alloy large-sized bar. The method comprises the following steps of: cogging and forging TC4 titanium alloy ingots for 2 to 3 heating times to obtain forging billets; 2, upsetting the forging billets repeatedly and performing drawing-out forging for 2 to 3 heating times; 3, upsetting the forging billets subjected to forging repeatedly and performing drawing-out forging for 3 to 5 heating times; and 4, performing chamfering round forging on the forging billets subjected to forging for 2 heating times to obtain the TC4 titanium alloy large-sized bar with the diameter of 200 to 400 mm and length of not less than 2,500 mm. The TC4 titanium alloy bar processed by the method has uniform and fine grains, few internal defects and high safety and accords with the domestic advanced level of the like products. In the processed TC4 titanium alloy bar, the room-temperature tensile strength is 920 to 960 MPa; the yield strength is 830 to 870 MPa; the elongation percentage is not less than 12 percent; the contraction ratio of the cross section is not less than 36 percent; flaw detection clutter reflects small signals; and the flaw detection level is high.

Description

technical field [0001] The invention belongs to the technical field of preparation of titanium alloy rods, and in particular relates to a processing method for large-scale rods of TC4 titanium alloys. Background technique [0002] Titanium alloy has the advantages of high specific strength, strong corrosion resistance, excellent high temperature performance, and good machinability. It is an important material used in aviation, aerospace, weapons and other fields. The aviation industry is the main application field of titanium alloys. TC4 is the alloy grade with the largest consumption, accounting for about 70% of the total output of titanium alloys, and is mainly used for structural parts of aircraft. With the development of the aviation industry, in order to improve the safety and reliability of the aircraft, extend the service life, and improve the structural benefits, the development trend of aircraft design is to reduce welding, and the load-bearing parts adopt large for...

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Problems solved by technology

With the development of the aviation industry, in order to improve the safety and reliability of the aircraft, extend the service life, and improve the structural benefits, the development trend of aircraft design is to reduce welding, and the load-bearing parts adopt large forgings and large integral forgings. In order to meet the needs of large forgings and large integral forgings The development and production of titanium alloys require the use of high-quality, large-scale titanium alloy rods. However, in the domestic production method of TC4 titanium alloy rods with a diameter of 100 mm or more, in order to ensure that the structure and performance are consistent and meet the requirements, it is necessary to repeat the process below the phase transition point. Upsetting and drawing forging, and the realization of upsetting and drawing forging is only limited to the axial direction. Due to the limitation of the upsetting and drawing forging method, the microstructure of the small deformation zone and the dead zone of deformation cannot be effectively refined at a lower temperature, and the microstructure The uniformity is poor, which makes the production cycle of domestic TC4 titanium alloy bars above Φ100mm long, the bar unit weight is small, the product quality consistency is poor, and the ultrasonic flaw detection level is low

At present, the maximum diameter of bars produced and applied in industrialization is Φ220mm, and the length of a single bar is only about 1.5 meters, which is difficult to meet the needs of domestic and foreign aviation, aerospace, shipping and other fields. However, it is still limited to the repeated upsetting and drawing technology of small billets, it is difficult to increase the length or unit weight of the bar, and there is still a large gap in the requirements for structure, ultrasonic flaw detection and quality consistency.

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