阅读说明：本技术 一种具有高强高韧近β型钛合金锻件锻造成形的制备方法 (Preparation method for forging and forming high-strength high-toughness β -type titanium alloy forging ) 是由 张鸿名 陈刚 王静 常旭升 韩飞 王卫卫 于 2020-02-28 设计创作，主要内容包括：本发明公开了一种具有高强高韧近β型钛合金锻件锻造成形的制备方法,包括：一、β相区开坯锻造；二、准β锻镦拔热变形；三、静态退火热处理；四、近β锻反复镦拔热变形；五、终锻成形水冷淬火；六、固溶时效处理。本发发明锻造出的近β钛合金锻件,力学性能好,强塑性匹配高,质量稳定可控,能够满足航空钛合金承力构件制造中对高性能近β型钛合金锻件的迫切需求。(The invention discloses a preparation method for forging and forming a near β type titanium alloy forged piece with high strength and high toughness, which comprises the steps of cogging and forging in a first β phase region, quasi- β forging, upsetting, drawing and thermal deformation, static annealing heat treatment, repeated upsetting, drawing and thermal deformation, finish forging, forming, water-cooling quenching, and solution aging treatment.)

1. A preparation method for forging and forming a β -type titanium alloy forging with high strength and high toughness is characterized by comprising the following steps of:

(1) β phase region cogging forging:

heating the nearly β type titanium alloy cast ingot to 200-300 ℃ above the phase transition temperature of β, preserving heat for 8-12 hours, repeatedly upsetting and drawing for 3 times by adopting a quick forging machine, controlling the total forging ratio to be 2.5-4.5, cooling to room temperature in air after forging, and carrying out surface grinding treatment;

(2) quasi β upset-draw hot deformation:

heating the blank processed in the step (1) to 5-10 ℃ above the phase transformation temperature of β ℃, and carrying out radial forging on a precision forging machine, wherein the forging ratio is controlled to be 5-8, and the finish forging temperature is not lower than 50 ℃ below the phase transformation temperature;

(3) static annealing heat treatment:

directly returning the blank processed in the step (2) to a furnace for annealing heat treatment, wherein the heat treatment temperature is 30-50 ℃ below the phase transition temperature of β, and the heat preservation time is 45-60 minutes;

(4) repeated upsetting-drawing thermal deformation of near β forging:

carrying out upsetting-drawing forging on the blank obtained by annealing treatment in the step (3) on a fast forging machine for 2-4 times, wherein the forging ratio of each time is 1.4-2, and carrying out remelting, heating and heat preservation in the forging process;

(5) finish forging forming water-cooling quenching:

closing the die and performing finish forging on the blank obtained in the step (4) below the phase transition temperature, heating the obtained formed forging to 10 ℃ below the phase transition temperature, discharging from the furnace and pre-cooling to 30 ℃ below the phase transition temperature, and cooling in water to room temperature;

(6) solid solution aging treatment:

and (5) cooling the formed forging in the step (5) for 4-6 hours, and then carrying out solid solution aging treatment to finally obtain a finished product of the titanium alloy forging.

2. The method for preparing the titanium alloy forging with high strength and toughness near β type according to claim 1, wherein the near β type titanium alloy ingot casting material in step (1) is one of Ti-55531, Ti-7333 and Ti-1023.

3. The method for preparing the titanium alloy forging with high strength and toughness near β type according to claim 1, wherein the forging speed of the radial forging process of the finish forging machine in step (2) is less than or equal to 20mm/s, and the total forging time is less than 20 minutes.

4. The method for preparing the titanium alloy forging with high strength and high toughness approximate to β type according to claim 1, wherein the heating temperature for remelting, heating and heat preservation in the forging process in step (4) is 30-50 ℃ below the phase transition temperature, and the heat preservation time is 60-90 minutes.

5. The method for preparing the titanium alloy forging with high strength and high toughness approximate to β type according to claim 1, wherein the finish forging temperature of the finish forging in the step (5) is 10-30 ℃ below the phase transformation temperature.

6. The method for preparing the titanium alloy forging with high strength and high toughness approximate to β type according to claim 1, wherein the die is preheated to 400 ℃ before finish forging in step (5), the die forging deformation is controlled to be 25-35%, and the die forging speed is 5 mm/s.

7. The method for preparing the forged piece of the titanium alloy with high strength and high toughness near β type according to claim 1, wherein the solution treatment method of the forged piece in step (6) comprises the steps of keeping the temperature below the phase transition temperature by 30-50 ℃ for 2-4 hours, then cooling the forged piece in air to room temperature, and keeping the temperature below the phase transition temperature by 200-300 ℃ for 4-7.5 hours, then cooling the forged piece in air to room temperature.

Technical Field

The invention belongs to the field of non-ferrous metal processing, and particularly relates to a preparation method for forging and forming a high-strength high-toughness β -close type titanium alloy forging.

Background

The nearly β type high-strength high-toughness titanium alloy has the characteristics of both the α + β type titanium alloy and the β type titanium alloy, has high strength, good toughness, fatigue resistance, better toughness matching, no obvious component segregation during processing, good hardenability and wider hot processing process range, and is particularly suitable for being applied to aviation parts such as fuselage frames, landing gears, connecting devices of wings and hangers and the like which bear huge stress.

The current conventional preparation method for forming the near β type titanium alloy forging comprises the steps of cogging above the phase transition temperature, repeatedly upsetting and drawing blanks in a two-phase region for multiple fire times, and finally forging and forming below the phase transition temperature, but the process generally cannot effectively inhibit the influence of initial tissue inheritance on the shape of the secondary α phase, has poor process stability, is difficult to obtain 539 homogeneous fine ternary tissues, causes the near 2 type titanium alloy forging to have poor plasticity and low fracture toughness and fatigue resistance.

Disclosure of Invention

The invention aims to solve the problem of making up the defects of the prior art and provides a preparation method for forging and forming a high-strength high-toughness near β type titanium alloy forging with simple process, strong operability and stable product quality.

The technical problem of the invention can be solved by the following technical scheme:

a preparation method for forging and forming a titanium alloy forging with high strength and high toughness approximate to β type comprises the following steps:

(1) β phase region cogging forging:

heating the nearly β type titanium alloy cast ingot to 200-300 ℃ above the phase transition temperature of β, preserving heat for 8-12 hours, repeatedly upsetting and drawing for 3 times by adopting a quick forging machine, controlling the total forging ratio to be 2.5-4.5, cooling to room temperature in air after forging, and carrying out surface grinding treatment;

(2) quasi β upset-draw hot deformation:

heating the blank processed in the step (1) to 5-10 ℃ above the phase transformation temperature of β ℃, and carrying out radial forging on a precision forging machine, wherein the forging ratio is controlled to be 5-8, and the finish forging temperature is not lower than 50 ℃ below the phase transformation temperature;

(3) static annealing heat treatment:

directly returning the blank processed in the step (2) to a furnace for annealing heat treatment, wherein the heat treatment temperature is 30-50 ℃ below the phase transition temperature of β, and the heat preservation time is 45-60 minutes;

(4) repeated upsetting-drawing thermal deformation of near β forging:

carrying out upsetting-drawing forging on the blank obtained by annealing treatment in the step (3) on a fast forging machine for 2-4 times, wherein the forging ratio of each time is 1.4-2, and carrying out remelting, heating and heat preservation in the forging process;

(5) finish forging forming water-cooling quenching:

closing the die and performing finish forging on the blank obtained in the step (4) below the phase transition temperature, heating the obtained formed forging to 10 ℃ below the phase transition temperature, discharging from the furnace and pre-cooling to 30 ℃ below the phase transition temperature, and cooling in water to room temperature;

(6) solid solution aging treatment:

and (5) cooling the formed forging in the step (5) for 4-6 hours, and then carrying out solid solution aging treatment to finally obtain a finished product of the titanium alloy forging.

Further, the near β type titanium alloy ingot casting material in the step (1) is one of Ti-55531, Ti-7333 and Ti-1023.

Further, the forging speed of the finish forging machine in the step (2) in the radial forging process is less than or equal to 20mm/s, and the total forging time is less than 20 minutes.

Further, the heating temperature of the remelting heating and heat preservation in the forging process in the step (4) is 30-50 ℃ below the phase transition temperature, and the heat preservation time is 60-90 minutes.

Further, the finish forging temperature of the finish forging in the step (5) is 10-30 ℃ below the transformation temperature.

Further, the die is preheated to 400 ℃ before the finish forging in the step (5), the die forging deformation is controlled to be 25-35%, and the die forging speed is 5 mm/s.

Further, the solution aging treatment method of the forging in the step (6) comprises the following steps: the solution treatment method is that the temperature is kept for 2 to 4 hours at the temperature of 30 to 50 ℃ below the phase transition temperature, and then the mixture is cooled to the room temperature in the air; the aging treatment method is to keep the temperature for 4 to 7.5 hours at the temperature of 200 ℃ and 300 ℃ below the phase transition temperature and then cool the mixture to the room temperature in the air.

Compared with the prior art, the invention has the following beneficial effects:

the invention provides a preparation method for forging and forming a near β type titanium alloy forging with high strength and high toughness, which fully utilizes a microstructure evolution mechanism under high-temperature deformation of a near β type titanium alloy, performs primary radial quasi β forging after cogging forging, can quickly break β matrix phase coarse grains, refines the grain size through a non-continuous dynamic recrystallization structure behavior, effectively inhibits the interference effect of initial structure inheritance on secondary β phase morphology in a subsequent processing process, is matched with static annealing heat treatment after radial quasi β forging deformation, can fully refine the grain size through a sub-dynamic recrystallization behavior, promotes the structure uniformity, eliminates the influence of a deformation texture on the subsequent forging process, fully refines the grain size through continuous dynamic recrystallization and β phase behavior in repeated upsetting β forging below a phase transition temperature, is heated and quenched on the upper part of a (β + β) area after final forging, uniformly precipitates martensite phases β' and α ″, obtains a ternary mechanical phase material formed by primary spheroidization α, fine sheet spheroidization α and fine solid solution transition β phase, and can realize uniform solid solution mechanical phase conversion of the near 8236.

The invention provides a preparation method for forging and forming a near β type titanium alloy forged piece with high strength and high toughness, wherein the forged near β type titanium alloy forged piece has good mechanical property, high strong plasticity matching and stable and controllable quality, and can meet the urgent requirements of manufacturing a high-performance near β type titanium alloy forged piece in an aviation titanium alloy bearing member.

Drawings

FIG. 1 is a microstructure view of a forged part prepared according to the first embodiment of the invention;

FIG. 2 is a microstructure diagram of a forged part prepared according to the second embodiment of the invention;

FIG. 3 is a microstructure diagram of a forged part prepared according to the third embodiment of the invention.

Detailed Description

The present invention will be further described below based on preferred embodiments with reference to the accompanying drawings.