Preparation method of large-size TC17 titanium alloy beta-forged blisk forge piece

Abstract

The invention relates to a preparation method of a large-size TC17 titanium alloy beta-forged blisk forge piece. The preparation method comprises the steps that TC17 titanium alloy bars are blanked into bar billets according to multiple lengths; the bar billets are subjected to common die forging to form a prefabricated blank; the pre-forged blank is machined into an annular prefabricated blank; gradient heating is conducted on the prefabricated blank to 20 DEG C-40 DEG C above phase transformation point through gradient heating, and the prefabricated blank is subjected to hot die forging to form a blisk forge piece blank by controlling constant strain rate to be 0.001s<-1>~0.01s<-1>; and after rapid air cooling to the room temperature, solid solution and aging heat treatment is conducted on the blisk forge piece blank. According to the method, common die forging and hot die forging are adopted for pre-forging and finish forging respectively, the large-size TC17 titanium alloy beta-forged blisk forge piece good in mold filling is obtained by optimizing the heating mode of the prefabricated blank in the beta forging process, the lubricating mode of a mold and the blank and the cooling mode after forging, the microstructure of each part of the forge piece is uniform, the tensile strength can meet the design requirement, and the obdurability matching is excellent.

Description

technical field [0001] The invention belongs to the technical field of thermomechanical treatment of integral blisk forgings, and in particular relates to a method for preparing large-size TC17 titanium alloy beta forged integral blisk forgings. Background technique [0002] TC17 titanium alloy is a high-strength, high-toughness and high-hardenability β-phase-rich two-phase titanium alloy with a service temperature of 427 ° C. The nominal composition is Ti-5Al-4Mo-4Cr-2Sn-2Zr. β forging refers to the forging of titanium alloy completely above the β transformation point, and the basket structure can be obtained. β-forged TC17 alloy forgings have high tensile strength, good fracture toughness and creep properties, and are widely used in the manufacture of aero-engine fans and compressor disks. [0003] The blisk is a new type of structural part designed to meet the needs of high-performance aeroengines, which integrates the engine rotor blades and discs. The main process of ...

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Problems solved by technology

[0006] Chinese patent "Forging method of TC17 alloy β-forging journal forging for aero-engine" (CN106694772B), discloses a method of preparing forgings by using isothermal extrusion instead of closed-die forging extrusion, avoiding large mold costs and forging Due to the shortcomings of long cycle time and high production cost, it can produce aviation TC17 alloy β-forged journal forgings with uniform structure and excellent comprehensive performance.

With the requirement of high thrust-to-weight ratio for aero-engines, the size of TC17 alloy fan disc forgings is continuously increasing and gradually upgraded to integral blisk forgings. The tensile strength of large-sized TC17 alloy integral blisk forgings prepared by the existing β forging technology cannot meet the requirements. Design requirements (≥1120MPa)

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