阅读说明：本技术 一种大规格ta15钛合金异形锻坯的锻造方法 (Forging method of large-size TA15 titanium alloy special-shaped forging stock ) 是由 郝芳 许恩恩 张慧杰 樊彦杰 雷锦文 王凯旋 楼美琪 杜予咺 刘向宏 于 2020-06-17 设计创作，主要内容包括：本发明公开的一种大规格TA15钛合金异形锻坯的锻造方法,包括以下步骤：步骤1、开坯锻造,步骤2、细晶化处理,步骤3、中间坯锻造,步骤4、成型锻造。本发明一种大规格TA15钛合金异形锻坯的锻造方法,通过对锻造火次和变形温度的合理配置、变形方式和成型方法的优化、锻造时的压下量和送进量等参数的合理设置,有效提高了锻坯的组织均匀性,使锻坯的探伤水平达到Φ2.0-9dB以上,同时减小了锻坯的各向异性。成功突破了TA15钛合金大规格异形锻坯的组织性能均匀性和稳定性控制技术,获得了各项技术指标满足要求的大规格异形锻坯制备技术。本发明生产效率高、可操作性强,适合大规模工业化生产。(The invention discloses a forging method of a large-size TA15 titanium alloy special-shaped forging stock, which comprises the following steps: step 1, cogging and forging, step 2, grain refining, step 3, forging of an intermediate blank, and step 4, forming and forging. The forging method of the large-size TA15 titanium alloy special-shaped forging stock effectively improves the tissue uniformity of the forging stock, enables the flaw detection level of the forging stock to reach phi 2.0-9dB above and simultaneously reduces the anisotropy of the forging stock by reasonably configuring the forging heat and deformation temperature, optimizing the deformation mode and the forming method and reasonably setting the parameters such as the reduction and feeding amount during forging. The method successfully breaks through the structural property uniformity and stability control technology of the TA15 titanium alloy large-size special-shaped forging stock, and obtains the large-size special-shaped forging stock preparation technology with various technical indexes meeting the requirements. The method has high production efficiency and strong operability, and is suitable for large-scale industrial production.)

1. A forging method of a large-specification TA15 titanium alloy special-shaped forging stock is characterized by comprising the following steps:

step 1, cogging and forging:

carrying out multi-fire cogging forging on TA15 titanium alloy ingots, wherein the cogging temperature is 1000-1200 ℃, the temperature is kept for 240-300min, the ingots are forged and deformed after being discharged from the furnace every fire, the total forging ratio is controlled between 18-30, after the blanks are obtained, air cooling is carried out to the room temperature, and surface damage clearing treatment is carried out;

step 2, grain refining treatment:

heating and insulating the blank processed in the step 1 at the temperature of 30-70 ℃ below the phase change point for 300-420min, and performing forging deformation for one time; then heating and preserving heat for 210-300min at the temperature of 30-50 ℃ above the phase transformation point, carrying out forging deformation for one time with the total forging ratio controlled between 12-16, transferring to a circulating water tank for cooling after the forging is finished, and carrying out surface damage clearing treatment after the blank is cooled to room temperature;

step 3, forging the intermediate blank:

heating and preserving the blank processed in the step 2 at the temperature of 20-40 ℃ below the phase change point for 240-360min, and performing forging deformation for one time or two times; then heating and preserving heat for 240-360min at the temperature of 30-50 ℃ below the phase transformation point, forging for multiple times with the total forging ratio controlled between 25-35, cooling to room temperature after the forging is finished, and performing surface damage clearing treatment;

Step 4, forming and forging:

heating and insulating the blank processed in the step 3 at the temperature of 30-50 ℃ below the phase change point for 240-360min, and performing forging deformation for one time; then heating and preserving heat for 180-240min at the temperature of 40-70 ℃ below the phase transformation point, forging for multiple times with total forging ratio controlled between 3.9-5.4, and cooling in air after forging to obtain the alloy.

2. The forging method of large-size TA15 titanium alloy special-shaped forging stock as claimed in claim 1, wherein the number of fire times for cogging forging the TA15 titanium alloy ingot in the step 1 is three fire times or four fire times.

3. The forging method of large-specification TA15 titanium alloy special-shaped forging stock as claimed in claim 1, wherein the forging ratio of the stock subjected to one-time forging deformation below the transformation point in the step 2 is 6-8.

4. The forging method of large-specification TA15 titanium alloy special-shaped forging stock as claimed in claim 1, wherein the forging ratio of the stock subjected to one-time forging deformation above the transformation point in the step 2 is between 4 and 8.

5. The forging method of large-specification TA15 titanium alloy special-shaped forging stock as claimed in claim 1, wherein the transfer time of transferring into a circulating water tank for cooling after the forging in the step 2 is not more than 120s, and the temperature of cooling water is not more than 80 ℃.

6. The forging method of large-specification TA15 titanium alloy special-shaped forging stock as claimed in claim 1, wherein the forging ratio of one-fire or two-fire forging deformation in the step 3 is controlled to be 6-8 per fire.

7. The forging method of large-specification TA15 titanium alloy special-shaped forging stock as claimed in claim 1, wherein the number of the multiple-fire forging in the step 3 is three or four, and the forging ratio of each fire is 6-7.

8. The forging method of large-specification TA15 titanium alloy special-shaped forging stock as claimed in claim 1, wherein the forging ratio of one-time forging deformation in the step 4 is 1.5.

9. The forging method of large-size TA15 titanium alloy special-shaped forging stock as claimed in claim 1, wherein the number of the multiple-fire forging in the step 4 is two or three, and the forging ratio of each fire is 1.2-1.3.

Technical Field

The invention belongs to the technical field of non-ferrous metal processing methods, and particularly relates to a forging method of a large-size TA15 titanium alloy special-shaped forging stock.

Background

The TA15 titanium alloy (nominal component is Ti-6Al-2Zr-1Mo-1V) is a typical near-alpha type titanium alloy, the phase transformation point of the alloy is generally between 980 ℃ and 1000 ℃, and the TA15 titanium alloy has good room temperature strength and high temperature strength, good thermal stability and welding performance, high specific strength, creep resistance and corrosion resistance. The TA15 titanium alloy is mainly applied to key bearing members of aviation equipment, such as bearing frames, beams and the like on an airplane body, and the key bearing members are ridge beams of the airplane and play an important role in ensuring the development and capability of the aviation equipment.

With the continuous development of the design and manufacturing technology of the aviation industry in China and the successive production of heavy equipment with extra-large tonnage, the requirements for further lightening the structural member of a novel airplane and integrating the structural member are higher and more updated, wherein TA15 is used as the integral frame of the main bearing member of the airplane and needs a large-sized forging blank with a larger specification and a 'convex' shaped structure, the development of the large-sized integral frame can further reduce the weight, eliminate the welding process, improve the production efficiency, and simultaneously improve the stability of the integral structure, thereby having great significance for the development of the aviation industry.

Disclosure of Invention

The invention aims to provide a forging method of a large-size TA15 titanium alloy special-shaped forging stock, which effectively improves the structural uniformity of the forging stock and reduces the anisotropy of the forging stock.

The technical scheme adopted by the invention is as follows: a forging method of a large-specification TA15 titanium alloy special-shaped forging stock comprises the following steps:

step 1, cogging and forging:

carrying out multi-fire cogging forging on TA15 titanium alloy ingots, wherein the cogging temperature is 1000-1200 ℃, the temperature is kept for 240-300min, the ingots are forged and deformed after being discharged from the furnace every fire, the total forging ratio is controlled between 18-30, after the blanks are obtained, air cooling is carried out to the room temperature, and surface damage clearing treatment is carried out;

step 2, grain refining treatment:

heating and insulating the blank processed in the step 1 at the temperature of 30-70 ℃ below the phase change point for 300-420min, and performing forging deformation for one time; then heating and preserving heat for 210-300min at the temperature of 30-50 ℃ above the phase transformation point, carrying out forging deformation for one time with the total forging ratio controlled between 12-16, transferring to a circulating water tank for cooling after the forging is finished, and carrying out surface damage clearing treatment after the blank is cooled to room temperature;

step 3, forging the intermediate blank:

heating and preserving the blank processed in the step 2 at the temperature of 20-40 ℃ below the phase change point for 240-360min, and performing forging deformation for one time or two times; then heating and preserving heat for 240-360min at the temperature of 30-50 ℃ below the phase transformation point, forging for multiple times with the total forging ratio controlled between 25-35, cooling to room temperature after the forging is finished, and performing surface damage clearing treatment;

Step 4, forming and forging:

heating and insulating the blank processed in the step 3 at the temperature of 30-50 ℃ below the phase change point for 240-360min, and performing forging deformation for one time; then heating and preserving heat for 180-240min at the temperature of 40-70 ℃ below the phase transformation point, forging for multiple times with total forging ratio controlled between 3.9-5.4, and cooling in air after forging to obtain the alloy.

The present invention is also characterized in that,

the firing frequency of the TA15 titanium alloy ingot in the step 1 for cogging forging is three or four.

In the step 2, the forging ratio of the blank subjected to one-time forging deformation below the phase change point is between 6 and 8.

In the step 2, the forging ratio of the blank subjected to one-time forging deformation above the phase change point is between 4 and 8.

And (3) transferring to a circulating water tank for cooling after the forging in the step 2 is finished for not more than 120s, wherein the temperature of cooling water is not higher than 80 ℃.

The forging ratio of forging deformation of one fire or two fires in the step 3 is controlled between 6 and 8 per fire.

The fire frequency of the multi-fire forging in the step 3 is three fire times or four fire times, and the forging ratio of each fire time is between 6 and 7.

The forging ratio of one-time forging deformation in the step 4 is 1.5.

In the step 4, the fire frequency of the multi-fire forging is two fire times or three fire times, and the forging ratio of each fire time is between 1.2 and 1.3.

The invention has the beneficial effects that: the forging method of the large-size TA15 titanium alloy special-shaped forging stock effectively improves the tissue uniformity of the forging stock, enables the flaw detection level of the forging stock to reach phi 2.0-9dB above and simultaneously reduces the anisotropy of the forging stock by reasonably configuring the forging heat and deformation temperature, optimizing the deformation mode and the forming method and reasonably setting the parameters such as the reduction and feeding amount during forging. The method successfully breaks through the structural property uniformity and stability control technology of the TA15 titanium alloy large-size special-shaped forging stock, and obtains the large-size special-shaped forging stock preparation technology with various technical indexes meeting the requirements. The method has high production efficiency and strong operability, and is suitable for large-scale industrial production.

Drawings

FIG. 1a) is a high magnification organization diagram of the forging billet pitch-1 obtained in the example 1 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet in the invention;

FIG. 1b) is a high magnification organization diagram of the forging billet pitch-2 obtained in the example 1 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet of the invention;

FIG. 1c) is a high-power structure diagram of the forging stock node number-3 obtained in the example 1 in the forging method of the large-size TA15 titanium alloy special-shaped forging stock;

FIG. 2a) is a high magnification organization diagram of the forging billet pitch-1 obtained in the example 2 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet of the invention;

FIG. 2b) is a high magnification organization diagram of the forging billet pitch-2 obtained in the example 2 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet of the invention;

FIG. 2c) is a high-power structure diagram of the forging billet pitch-3 obtained in the example 2 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet;

FIG. 3a) is a high magnification organization chart of the forging billet node number-1 obtained in the example 3 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet of the invention;

FIG. 3b) is a high magnification organization diagram of the forging billet pitch-2 obtained in the example 3 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet of the invention;

FIG. 3c) is a high-power structure diagram of the forging stock node number-3 obtained in the example 3 in the forging method of the large-size TA15 titanium alloy special-shaped forging stock;

FIG. 4a) is a high magnification organization chart of the forging billet node number-1 obtained in the example 4 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet of the invention;

FIG. 4b) is a high magnification organization diagram of the forging billet pitch-2 obtained in the example 4 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet of the invention;

FIG. 4c) is a high power structure diagram of the forging billet pitch-3 obtained in the example 4 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet;

FIG. 5a) is a high magnification organization chart of the forging billet pitch-1 obtained in the example 5 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet in the invention;

FIG. 5b) is a high magnification organization diagram of the forging billet pitch-2 obtained in the example 5 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet of the invention;

FIG. 5c) is a high power structure diagram of the forging billet pitch-3 obtained in the example 5 in the forging method of the large-size TA15 titanium alloy special-shaped forging billet;

FIG. 6 is a comparison chart of the mechanical property data of the forged blanks obtained in examples 1-5 in the forging method of the large-size TA15 titanium alloy special-shaped forged blank.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention provides a forging method of a large-size TA15 titanium alloy special-shaped forging stock, which has the contour dimension of (80-200) × (700-900) × (1500-3500) mm and is of a convex structure, and comprises the following steps:

step 1, cogging and forging:

carrying out three-fire or four-fire cogging forging on the TA15 titanium alloy ingot, wherein the cogging temperature is 1000-1200 ℃, the temperature is kept for 240-300min, the ingot is forged and deformed after each fire is discharged, the total forging ratio is controlled between 18-30, the obtained blank is air-cooled to the room temperature, and the surface damage clearing treatment is carried out;

step 2, grain refining treatment:

heating and insulating the blank processed in the step 1 at the temperature of 30-70 ℃ below the phase change point for 300-420min, and performing forging deformation for one time, wherein the forging ratio is 6-8; then heating and preserving heat at 30-50 ℃ above the phase transformation point for 210-fold for 300min, carrying out one-time forging deformation, controlling the forging ratio to be 4-8 and the total forging ratio to be 12-16, transferring into a circulating water tank for cooling after the forging is finished, wherein the transfer time is not more than 120s, the cooling water temperature is not higher than 80 ℃, and carrying out surface cleaning treatment after the blank is cooled to room temperature;

step 3, forging the intermediate blank:

Heating and insulating the blank processed in the step 2 at the temperature of 20-40 ℃ below the phase change point for 240-360min, and performing forging deformation for one time or two times, wherein the forging ratio is controlled between 6-8 per time; then heating and preserving heat for 240-360min at the temperature of 30-50 ℃ below the phase transformation point, forging for three times or four times, wherein the forging ratio of each time is 6-7, the total forging ratio is controlled to be 25-35, cooling to room temperature after forging, and performing surface damage clearing treatment; the purpose is to make the coarse and flaky alpha phase change into fine equiaxial.

Step 4, forming and forging:

heating and insulating the blank processed in the step 3 at the temperature of 30-50 ℃ below the phase transformation point for 240-360min, and performing forging deformation for one time with the forging ratio of 1.5; then heating and preserving heat for 180-240min at the temperature of 40-70 ℃ below the phase transition point, forging for two times or three times, wherein the forging ratio of each time is 1.2-1.3, the total forging ratio is controlled to be 3.9-5.4, and air cooling is adopted after forging to obtain the alloy. The forming process adopts an operation mode of small feeding amount and small deformation amount, and the uniform deformation of the forging stock is fully ensured. In the forging process, the selection of the tool and the die and the control of the deformation should avoid the generation of cracks on the surface of the material as much as possible until the forging of the finished product is completed.

Through the mode, the forging method of the large-size TA15 titanium alloy special-shaped forging stock adopts a high-low-high-low cyclic forging process. Firstly, repeatedly upsetting and drawing out a TA15 titanium alloy ingot with high primary alpha phase content for many times in a high-temperature beta region above a phase transformation point to fully crush an as-cast structure with poor mechanical property, and improving the structure uniformity and directionality of a large ingot under a large enough deformation. Then, forging, refining and homogenizing alpha grains at a proper temperature and deformation below a phase transformation point, combining upsetting and drawing-out at the temperature above the phase transformation point, and nucleating to generate new beta grains by utilizing a phase transformation recrystallization principle to obtain an ideal initial state with uniform fineness, thereby providing an ideal platform for refining grains and homogenizing tissues below the subsequent phase transformation point. And finally, deforming in an alpha + beta two-phase region to ensure that coarse and flaky alpha phase is transformed into a fine isometric primary alpha phase, and simultaneously controlling the heating temperature in a narrow range in a key forming process, and adopting small deformation and multi-pass rapid deformation to prevent the forging stock from deforming unevenly, prevent surface cracks from being generated, and avoid the phenomenon of over-burning of the center to influence the structure performance of the material. By reasonably configuring the forging heat number and deformation temperature, optimizing the deformation mode and the forming method and reasonably setting the reduction and feeding amount during forging, the structural uniformity of the forging blank is effectively improved, the flaw detection level of the obtained large-size special-shaped forging blank reaches over phi 2.0-9dB, the high-low order structure is uniform, and the mechanical properties of the forging blank after ordinary annealing can meet the corresponding standard requirements.