Forging forming method for TA15 titanium alloy forge piece with high strength and high tenacity

Abstract

The invention belongs to the technical field of material machining, and particularly discloses a forging forming method for a TA15 titanium alloy forge piece with high strength and high tenacity. Themethod comprises the following steps of 1, freely forging a blank, wherein the black is preheated under the temperature of Tbeta-30-Tbeta-50 DEG C for heat preservation; free forging is performed after the blank is discharged out of a furnace; 2, performing die forging, wherein the blank is preheated under the temperature of Tbeta-30-Tbeta-50 DEG C for heat preservation; die forging is performed after the blank is discharged out of the furnace; the blank is preheated under the temperature of Tbeta-10-Tbeta-30 DEG C for heat preservation; final-heating-number die forging is performed after theblank is discharged; 3, performing thermal treatment. The TA15 titanium alloy forge piece with high strength and high tenacity can be obtained through the method. The forging forming method can obtainthe TA15 titanium alloy forge piece with high strength, high plasticity, high tenacity and high impact matching, is widely used for an airplane body component, the service performance of an airplaneis improved, and the service life of the airplane is prolonged.

Description

technical field [0001] The invention relates to the technical field of material processing, in particular to a forging forming method of a TA15 titanium alloy forging with high strength and high toughness. Background technique [0002] TA15 titanium alloy is a near-alpha titanium alloy with high Al equivalent, and its nominal chemical composition (wt%) is Ti-6.5Al-2Zr-1Mo-1V. The alloy has moderate room temperature and high temperature strength, good thermal stability and weldability. TA15 titanium alloy is mainly used to manufacture aircraft load-bearing parts that work for a long time below 500 °C. [0003] The corresponding aircraft model standards and industry standards stipulate that the tensile strength of TA15 titanium alloy aircraft structure forgings must be ≥ 930MPa, and the impact ≥ 40J / cm 2 , fracture toughness ≥ 60MPa.m 1 / 2 . In actual production, the traditional forging process has the following problems: 1) With the improvement of the production process of...

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Problems solved by technology

In actual production, the traditional forging process has the following problems: 1) With the improvement of the production process of sponge titanium used in the production of TA15 titanium alloy raw materials, the quality and purity of sponge titanium have been greatly improved. The content of chemical elements such as O and N is reduced, resulting in low content of chemical elements such as O and N in the TA15 titanium alloy bar used for forgings, which is close to the lower limit of the standard range, and the low content of elements such as O and N has a negative impact on the strength of forgings. Therefore, it is necessary to optimize the forging process and heat treatment process, and improve the strength of forgings when the chemical composition of raw materials is unfavorable to the strength of forgings. 2) Due to the low degree of alloying of TA15 titanium alloy and the relatively small content of β-stable elements, it is generally considered that TA15 titanium alloy is a non-heat treatment strengthened titanium alloy. In general, the traditional forging process adopts the heat treatment system of ordinary annealing, which loses the opportunity to adjust and improve the strength and toughness of TA15 titanium alloy through heat treatment.

However, tests have shown that the strength of TA15 titanium alloy can be increased by 30-60MPa by adopting solid solution or solid solution + aging strengthening heat treatment process instead of the traditional ordinary annealing process. Compared with other high-alloyed titanium alloys, its strengthening effect Although weak, it can also solve the problem of unqualified strength or low affluence of TA15 titanium alloy forgings to a considerable extent. It is also a heat treatment process that is very worth adopting and can solve practical problems; 3) corresponding aircraft model standards and industries The standard stipulates the content of the primary α phase in the microstructure of TA15 titanium alloy relatively broadly. Therefore, when the traditional forging process is formulated, generally all forging fires adopt a uniform blank heating temperature, and the selection range of the heating temperature is generally T β -30℃~T β -50°C, the primary α phase content of the microstructure of the final forging is generally about 40%, and the primary α phase content of this metallographic structure cannot make the forging achieve the best strength and toughness matching

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