阅读说明：本技术 一种Ti-Al-V-Fe合金无缝管的短流程制备方法 (Short-process preparation method of Ti-Al-V-Fe alloy seamless tube ) 是由 张玉勤 蒋业华 邓亚杰 张关梅 于 2020-11-23 设计创作，主要内容包括：本发明提供一种Ti-Al-V-Fe合金无缝管的短流程制备方法,其特征在于包括下列各步骤：1)备料,2)混料、压块,3)将料放于电子束枪EB炉内,4)真空熔炼得Ti-Al-V-Fe合金圆锭,5)在锭的两端打定心孔、送二辊斜轧机斜轧穿孔,6)送三辊连轧机连轧,7)加热定径得无缝管材,8)退火处理得Ti-Al-V-Fe合金无缝管。其金相组织均匀、高低密度夹杂少、高纯净,且工艺流程短,力学性能优于现有技术水平,综合成材率提高到85%以上,生产成本降低20～30%,具有明显的市场应用前景。(The invention provides a short-process preparation method of a Ti-Al-V-Fe alloy seamless tube, which is characterized by comprising the following steps of: 1) preparing materials, 2) mixing and briquetting, 3) putting the materials into an electron beam gun EB furnace, 4) carrying out vacuum melting to obtain a Ti-Al-V-Fe alloy round ingot, 5) punching centering holes at two ends of the ingot, carrying out oblique rolling and perforation by a two-roll oblique rolling machine, 6) carrying out continuous rolling by a three-roll continuous rolling machine, 7) carrying out heating and sizing to obtain a seamless pipe, and 8) carrying out annealing treatment to obtain the Ti-Al-V-Fe alloy seamless pipe. The method has the advantages of uniform metallographic structure, less high-low density impurities, high purity, short process flow, mechanical property superior to the prior art, comprehensive yield increased to over 85 percent, production cost reduced by 20-30 percent, and obvious market application prospect.)

1. A short-process preparation method of a Ti-Al-V-Fe alloy seamless tube is characterized by comprising the following steps:

(1) preparing materials according to the following mass ratio:

4.5-5.0 wt.% of Al-V intermediate alloy

Aluminum bean 3.5-3.98 wt. -%)

1.2-1.8 wt.% of high purity iron

0.1-0.15 wt.% of titanium dioxide

Titanium sponge balance

The total of the components is 100 wt.%;

(2) mixing the prepared materials in the step (1), taking a proper amount of mixture as bulk materials, pressing the rest of the mixture into blocks, drying the blocks at 100-120 ℃ for 5-6 hours, and cooling the blocks along with a furnace to obtain pressed blocks;

(3) laying the bulk material in the step (2) in a cooling bed of an EB furnace provided with a seven-rod electron gun, and then putting a proper amount of briquetting material in the step (2) into a feeding area of the EB furnace;

(4) under a vacuum of 1.8X 10^-3～3.5×10^-3When torr, opening No. 1 to No. 5 electron guns to smelt the bulk material in the cooling bed, controlling the voltage of No. 1 to No. 5 electron guns to be 29.5 to 30.5KV and the current to be 3.3 to 4.3A, after smelting for 100 to 120min, closing the electron guns, cooling for 20 to 40min, pushing the briquetting material in the feeding area into the smelting area, simultaneously opening No. 1 to No. 7 electron guns to continue smelting, controlling the voltage of No. 1 to No. 7 electron guns to be 29.5 to 30.5KV, controlling the current of No. 1 to No. 2 electron guns to be 2.3 to 3.0A, the current of No. 3 to No. 4 electron guns to be 5.3 to 6A, the current of No. 5 electron guns to be 3.6 to 4.6A, the current of No. 6 to No. 7 electron guns to be 1.6 to 2.6A, simultaneously keeping the ingot pulling speed of 12 to 18mm/min, thus continuously pushing, melting and pulling ingots till the smelting is completed, then cooling to the ingot from a crystallizer, taking out, polishing the surface of the ingot, and peeling off the ingot, obtaining a Ti-Al-V-Fe alloy round ingot;

(5) punching centering holes at two ends of the Ti-Al-V-Fe alloy round ingot obtained in the step (4), feeding the round ingot into a heating furnace, heating to 1100-1200 ℃, preserving heat for 6-8 hours, feeding the round ingot into a two-roll skew rolling mill, performing skew rolling perforation, and controlling: the total reduction rate is 10-15%, the pre-top reduction rate is 6-8%, the ellipticity coefficient is 1.11-1.18, the perforation speed is 0.18-0.42 m/s, and the temperature is 1080-1120 ℃, so that a perforated pipe is obtained;

(6) and (5) sending the perforated pipe in the step (5) to a three-roll continuous rolling mill for continuous rolling, and controlling: the total reduction rate is 12-18%, the ovality coefficient is 1.05-1.15, the perforation speed is 0.5-1 m/s, and the temperature is 900-950 ℃, so as to obtain a continuous rolling pipe;

(7) feeding the continuously rolled pipe in the step (6) into a heating furnace, heating to 800-900 ℃, feeding the pipe into a sizing mill for sizing, and controlling the sizing rate to be 0.6-1 m/s to obtain a seamless pipe;

(8) and (4) annealing the seamless pipe material obtained in the step (7) at the temperature of 850-900 ℃ for 2-3 h, and cooling to room temperature to obtain the Ti-Al-V-Fe alloy seamless pipe.

2. The short-run production method of a Ti-Al-V-Fe alloy seamless tube according to claim 1, wherein in the step (5), after the Ti-Al-V-Fe alloy round ingot is heated, a glass frit lubricant is applied to one end close to the plug before entering the skew rolling mill, and a glass frit lubricant wrapped with tinfoil is inserted into the centering hole to prevent defects from being generated on the inner wall of the tube during the piercing process.

3. The short-run production method of a Ti-Al-V-Fe alloy seamless tube according to claim 1, characterized in that the Ti-Al-V-Fe alloy seamless tube of the step (8) has the composition: al: 3.5wt.% to 4.5wt.%, V: 2.0 wt.% to 3.0 wt.%, Fe: 1.2-1.8 wt.%, 0.2-0.3 wt.% of O, and the balance Ti.

Technical Field

The invention relates to a short-process preparation method of a Ti-Al-V-Fe alloy seamless tube, belonging to the technical field of rolling of non-ferrous metals.

Background

The Ti-4Al-2.5V-1.5Fe alloy is a low-cost alpha + beta double-phase medium-high-strength titanium alloy developed on the basis of Ti-6Al-4V alloy, the mechanical property of the alloy is equivalent to that of the Ti-6Al-4V alloy, the alloy has good plasticity and toughness, the alloy can be subjected to hot processing and cold processing, various types of products such as plates, strips, pipes, bars and the like can be processed, and simultaneously, the alloy uses cheap Fe elements to replace partial expensive V elements, so that the alloy cost is reduced. Therefore, the method has wide application prospect in the fields of aerospace, ocean engineering, chemical engineering, electric power and the like.

However, the Ti-Al-V-Fe alloy seamless tube prepared by the prior art usually adopts the following process flow: firstly, mixing titanium sponge and alloy raw materials, pressing and welding the mixture to form an electrode, smelting the electrode into a round ingot through a vacuum consumable arc furnace (VAR) for 2-3 times, then forging the round ingot, then drilling and extruding or obliquely punching, and finally preparing finished pipes with different specifications and purposes through rolling, drawing, spinning and other methods. Therefore, the process flow is long, the comprehensive yield is low, the ultra-long pipe is difficult to obtain, the cost of the pipe is high, and the application is greatly limited. Therefore, there is a need for improvements in the prior art.

Disclosure of Invention

In order to overcome the defects of the existing Ti-Al-V-Fe titanium alloy seamless tube preparation method, the invention provides a short-process preparation method of the Ti-Al-V-Fe alloy seamless tube, which is characterized by comprising the following steps:

(1) preparing materials according to the following mass ratio:

4.5-5.0 wt.% of Al-V intermediate alloy

Aluminum bean 3.5-3.98 wt. -%)

1.2-1.8 wt.% of high purity iron

0.1-0.15 wt.% of titanium dioxide

Titanium sponge balance

The total of the components is 100 wt.%;

(2) mixing the prepared materials in the step (1), taking a proper amount of mixture as bulk materials, pressing the rest of the mixture into blocks, drying the blocks at 100-120 ℃ for 5-6 hours, and cooling the blocks along with a furnace to obtain pressed blocks;

(3) laying the bulk material in the step (2) in a cooling bed of an EB furnace provided with a seven-rod electron gun, and then putting a proper amount of briquetting material in the step (2) into a feeding area of the EB furnace;

(4) under a vacuum of 1.8X 10^-3～3.5×10^-3When torr is reached, opening No. 1-5 electron guns to smelt the bulk materials in the cooling bed, controlling the voltage of No. 1-5 electron guns to be 29.5-30.5 KV and the current to be 3.3-4.3A, and closing the electron guns after smelting for 100-120 min; after cooling for 20-40 min, pushing the briquetting material in the feeding area into a smelting area, simultaneously starting No. 1-7 electron guns to continue smelting, controlling the voltage of the No. 1-7 electron guns to be 29.5-30.5 KV, the current of the No. 1-2 electron guns to be 2.3-3.0A, the current of the No. 3-4 electron guns to be 5.3-6A, the current of the No. 5 electron guns to be 3.6-4.6A and the current of the No. 6-7 electron guns to be 1.6-2.6A, simultaneously keeping the ingot pulling speed of 12-18 mm/min, continuously pushing, melting and pulling ingots till smelting is completed, then cooling to 80-100 ℃, taking out the cast ingots from a crystallizer, cooling to room temperature, and carrying out surface peeling and polishing treatment to obtain Ti-Al-V-Fe alloy round ingots;

(5) punching centering holes at two ends of the Ti-Al-V-Fe alloy round ingot obtained in the step (4), feeding the round ingot into a heating furnace, heating to 1100-1200 ℃, preserving heat for 6-8 hours, feeding the round ingot into a two-roll skew rolling mill, performing skew rolling perforation, and controlling: the total reduction rate is 10-15%, the pre-top reduction rate is 6-8%, the ellipticity coefficient is 1.11-1.18, the perforation speed is 0.18-0.42 m/s, and the temperature is 1080-1120 ℃, so that a perforated pipe is obtained;

(6) and (5) sending the perforated pipe in the step (5) to a three-roll continuous rolling mill for continuous rolling, and controlling: the total reduction rate is 12-18%, the ovality coefficient is 1.05-1.15, the perforation speed is 0.5-1 m/s, and the temperature is 900-950 ℃, so as to obtain a continuous rolling pipe;

(7) feeding the continuously rolled pipe in the step (6) into a heating furnace, heating to 800-900 ℃, feeding the pipe into a sizing mill for sizing, and controlling the sizing rate to be 0.6-1 m/s to obtain a seamless pipe;

(8) and (4) annealing the seamless pipe material obtained in the step (7) at the temperature of 850-900 ℃ for 2-3 h, and cooling to room temperature to obtain the Ti-Al-V-Fe alloy seamless pipe.

In the step (5), after the Ti-Al-V-Fe alloy round ingot is heated, before the Ti-Al-V-Fe alloy round ingot enters the inclined rolling mill, a glass powder lubricant is required to be coated on one end close to the top, and meanwhile, the glass powder lubricant wrapped by the tinfoil is filled into the centering hole, so that defects are prevented from being generated on the inner wall of the pipe in the perforating process.

The Ti-Al-V-Fe alloy seamless tube obtained in the step (8) comprises the following components: al: 3.5wt.% to 4.5wt.%, V: 2.0 wt.% to 3.0 wt.%, Fe: 1.2-1.8 wt.%, 0.2-0.3 wt.% of O, and the balance Ti.

The invention has the following advantages and beneficial effects: the Ti-Al-V-Fe alloy seamless tube obtained by the technical scheme has uniform components and tissues, less high-low density impurities and high purity, does not need forging in the processing process, directly sends the smelted cast ingot to a two-roll oblique rolling puncher to prepare a perforated seamless tube, and then obtains a product through three-roll continuous rolling, sizing and annealing, thereby not only shortening the process flow of the titanium alloy seamless tube, but also having mechanical properties superior to the level of the preparation in the prior art. The method has the advantages of simple process, convenient operation and short process flow, improves the comprehensive yield of the seamless tube to about 85 percent, reduces the production cost by 20 to 30 percent, and has obvious market application prospect.

Drawings

FIG. 1 is a process flow diagram of the present invention.

FIG. 2 is a metallographic structure diagram of a pipe obtained in example 1 of the present invention.

FIG. 3 is a metallographic structure diagram of a pipe obtained in example 2 of the present invention.

FIG. 4 is a metallographic structure diagram of a pipe obtained in example 3 of the present invention.

FIG. 5 is a graph of the mechanical properties of the pipe obtained in example 1 of the present invention.

FIG. 6 is a mechanical property diagram of the pipe obtained in example 2 of the present invention.

FIG. 7 is a graph of the mechanical properties of the pipe obtained in example 3 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but the scope of the present invention is not limited to the description.

Example 1

A short-process preparation method of a Ti-Al-V-Fe alloy seamless tube is characterized by comprising the following steps:

(1) preparing materials according to the following mass ratio:

aluminium vanadium master alloy 4.5wt. -%)

Aluminum bean 3.5wt.%

1.2 wt.% of high purity iron

0.1 wt.% of titanium dioxide

Titanium sponge 90.7 wt.%;

(2) mixing the prepared materials in the step (1), taking a proper amount of the mixture as bulk materials, pressing the rest of the mixture into blocks, drying the blocks at 100 ℃ for 6 hours, and cooling the blocks along with a furnace to obtain pressed blocks;

(3) laying the bulk material in the step (2) in a cooling bed of an EB furnace provided with a seven-rod electron gun, and then putting a proper amount of briquetting material in the step (2) into a feeding area of the EB furnace;

(4) under a vacuum of 1.8X 10^-3When torr is used, opening No. 1-5 electron guns to smelt the bulk material in the cooling bed, controlling the voltage of No. 1-5 electron guns to be 29.5KV and the current to be 3.3A, after smelting for 100min, closing the electron guns, after cooling for 20min, pushing the briquetting material in the feeding area into the smelting area, simultaneously opening No. 1-7 electron guns to continue smelting, controlling the voltage of No. 1-7 electron guns to be 29.5KV, the current of No. 1-2 electron guns to be 2.3A, the current of No. 3-4 electron guns to be 5.3A, the current of No. 5 electron guns to be 3.6A and the current of No. 6-7 electron guns to be 1.6A, simultaneously keeping the ingot pulling speed of 12mm/min, continuously pushing, melting and ingot pulling until smelting is finished, then cooling to 80 ℃, and finally, carrying out ingot castingTaking out the alloy from the crystallizer, cooling to room temperature, and obtaining a Ti-Al-V-Fe alloy round ingot after surface peeling and polishing treatment;

(5) and (4) punching centering holes at two ends of the Ti-Al-V-Fe alloy round ingot in the step (4), then sending the round ingot into a heating furnace to be heated to 1100 ℃, preserving heat for 8 hours, smearing glass powder lubricant at one end close to the top before entering an inclined rolling mill after heating, and simultaneously filling the glass powder lubricant wrapped by tinfoil into the centering holes to prevent the inner wall of the pipe from generating defects in the perforating process. Then the steel pipe is sent to a two-roller skew rolling mill for skew rolling and piercing, and the control: the total reduction rate is 10 percent, the pre-top reduction rate is 6 percent, the ovality coefficient is 1.11, the perforation speed is 0.18m/s, and the temperature is 1080 ℃, so that a perforated pipe is obtained;

(6) and (5) sending the perforated pipe in the step (5) to a three-roll continuous rolling mill for continuous rolling, and controlling: the total reduction rate is 12 percent, the ovality coefficient is 1.05, the perforation speed is 0.5m/s, and the temperature is 900 ℃, so as to obtain a continuous rolling pipe;

(7) feeding the continuously rolled pipe in the step (6) into a heating furnace, heating to 800 ℃, feeding the pipe into a sizing mill for sizing, and controlling the sizing rate to be 0.6m/s to obtain a seamless pipe;

(8) annealing the seamless pipe in the step (7) at 850 ℃ for 3h, and cooling to room temperature to obtain a Ti-Al-V-Fe alloy seamless pipe;

the Ti-Al-V-Fe alloy seamless tube comprises the following components: al: 4.05wt.%, V: 2.38wt.%, Fe: 1.47wt.%, O:0.25 wt.%, balance Ti;

the mechanical properties are shown in table 1 and fig. 5:

TABLE 1

Sample number	Rm/MPa	Rp0.2/MPa	A/%
				1	910.3	853.2	10.56
2	912.5	855.2	10.46
				3	910.2	853.2	10.36
4	910.4	850.3	10.33
				5	913.2	853.6	10.46
6	912.2	855.2	10.36
				Mean value of	911.5	853.5	10.43

Through mechanical property detection, the mechanical properties of the annealed seamless pipe can meet the requirements, and the obtained seamless pipe has the dimensions of phi 180 multiplied by 12 multiplied by 11452mm (outer diameter multiplied by wall thickness multiplied by length).

Example 2

A short-process preparation method of a Ti-Al-V-Fe alloy seamless tube is characterized by comprising the following steps:

(1) preparing materials according to the following mass ratio:

the aluminum vanadium alloy was 4.7 wt.%,

1.6 wt.% of high purity iron,

3.75 wt.% of aluminum beans,

titanium dioxide 0.13 wt.%,

titanium sponge 89.82 wt.%;

(2) mixing the prepared materials in the step (1), taking a proper amount of the mixture as bulk materials, pressing the rest of the mixture into blocks, drying the blocks at 120 ℃ for 5 hours, and cooling the blocks along with a furnace to obtain pressed blocks;

(3) laying the bulk material in the step (2) in a cooling bed of an EB furnace provided with a seven-rod electron gun, and then putting a proper amount of briquetting material in the step (2) into a feeding area of the EB furnace;

(4) under vacuum degree of 3.5X 10^-3When torr is needed, the No. 1 to No. 5 electron guns are started to smelt the bulk material in the cooling bed, the voltage of the No. 1 to No. 5 electron guns is controlled to be 30.5KV, the current is controlled to be 4.3A, after 120min of smelting, the electron guns are closed, after 40min of cooling, the pressed block material is pushed into a smelting zone, meanwhile, opening No. 1 to No. 7 electron guns to continue smelting, continuously pushing a pressing block material into a feeding area of the EB furnace, controlling the voltage of the No. 1 to No. 7 electron guns to be 30.5KV, the current of the No. 1 to No. 2 electron guns to be 3.0A, the current of the No. 3 to No. 4 electron guns to be 6A, the current of the No. 5 electron gun to be 4.6A and the current of the No. 6 to No. 7 electron guns to be 2.6A, keeping the ingot pulling speed of 18mm/min, continuously pushing, melting and pulling the ingot in the way until the smelting is finished, then cooling to 100 ℃, taking the ingot out of the crystallizer, cooling to room temperature, and performing surface peeling and polishing treatment to obtain a Ti-Al-V-Fe alloy round ingot;

(5) and (4) punching centering holes at two ends of the Ti-Al-V-Fe alloy round ingot in the step (4), then sending the round ingot into a heating furnace to heat to 1150 ℃, preserving heat for 7 hours, after heating, smearing glass powder lubricant at one end close to the top before entering an inclined rolling mill, and simultaneously filling the glass powder lubricant wrapped by tinfoil into the centering holes to prevent the inner wall of the pipe from generating defects in the perforating process. Then the steel pipe is sent to a two-roller skew rolling mill for skew rolling and piercing, and the control: the total reduction rate is 12 percent, the reduction rate before jacking is 7 percent, the ovality coefficient is 1.16, the perforation speed is 0.3m/s, and the temperature is 1100 ℃, thus obtaining the perforated pipe;

(6) and (5) sending the perforated pipe in the step (5) to a three-roll continuous rolling mill for continuous rolling, and controlling: the total reduction rate is 15 percent, the ovality coefficient is 1.10, the perforation speed is 0.8m/s, and the temperature is 925 ℃, so that a continuous rolling pipe is obtained;

(7) feeding the continuously rolled pipe in the step (6) into a heating furnace, heating to 850 ℃, feeding the pipe into a sizing mill for sizing, and controlling the sizing rate to be 0.8m/s to obtain a seamless pipe;

(8) annealing the seamless pipe in the step (7) at 875 ℃ for 2.5h, and cooling to room temperature to obtain a Ti-Al-V-Fe alloy seamless pipe;

the Ti-Al-V-Fe alloy seamless tube comprises the following components: al: 4.13wt.%, V: 2.48wt.%, Fe: 1.62wt.%, O:0.27 wt.%, balance Ti;

the mechanical properties are shown in table 2 and fig. 6:

TABLE 2

Sample number	Rm/MPa	Rp0.2/MPa	A/%
				1	912.2	843.9	10.61
2	909.9	840.2	10.53
				3	920.3	845.2	10.96
4	915.2	840.3	10.64
				5	912.6	846.1	11.03
6	915.3	840.2	10.96
				Mean value of	914.3	842.7	10.78

The mechanical property detection shows that the mechanical property of each part can meet the requirement, and the obtained seamless pipe has the size phi of 180 multiplied by 12 multiplied by 10765mm (outer diameter multiplied by wall thickness multiplied by length).

Example 3

A short-process preparation method of a Ti-Al-V-Fe alloy seamless tube is characterized by comprising the following steps:

(1) preparing materials according to the following mass ratio:

the aluminum vanadium alloy has 5wt.%,

1.8 wt.% of high purity iron,

3.98 wt.% of aluminum beans,

titanium dioxide 0.15 wt.%,

titanium sponge 89.07 wt.%;

(2) mixing the prepared materials in the step (1), taking a proper amount of the mixture as bulk materials, pressing the rest of the mixture into blocks, drying the blocks at 110 ℃ for 5 hours, and cooling the blocks along with a furnace to obtain pressed blocks;

(3) laying the bulk material in the step (2) in a cooling bed of an EB furnace provided with a seven-rod electron gun, and then putting a proper amount of briquetting material in the step (2) into a feeding area of the EB furnace;

(4) under vacuum degree of 2.5X 10^-3When torr is needed, the No. 1 to No. 5 electron guns are started to smelt the bulk material in the cooling bed, the voltage of the No. 1 to No. 5 electron guns is controlled to be 30KV, the current is controlled to be 3.8A, after smelting is carried out for 110min, the electron guns are closed, after cooling is carried out for 30min, the pressed block material is pushed into a smelting zone, meanwhile, opening No. 1 to No. 7 electron guns to continue smelting, continuously pushing a pressing block material into a feeding area of the EB furnace, controlling the voltage of the No. 1 to No. 7 electron guns to be 30KV, the current of the No. 1 to No. 2 electron guns to be 2.8A, the current of the No. 3 to No. 4 electron guns to be 5.8A, the current of the No. 5 electron guns to be 4.1A and the current of the No. 6 to No. 7 electron guns to be 1.9A, keeping the ingot pulling speed of 16mm/min, continuously pushing, melting and pulling the ingot in the way until the smelting is finished, then cooling to 90 ℃, taking the ingot out of the crystallizer, cooling to room temperature, and performing surface peeling and polishing treatment to obtain a Ti-Al-V-Fe alloy round ingot;

(5) and (4) punching centering holes at two ends of the Ti-Al-V-Fe alloy round ingot in the step (4), then sending the round ingot into a heating furnace, heating to 1200 ℃, and preserving heat for 6 hours. After heating, before entering the inclined rolling mill, one end close to the top is required to be coated with a glass powder lubricant, and meanwhile, the glass powder lubricant wrapped by tinfoil is stuffed in the centering hole, so that defects on the inner wall of the pipe in the perforating process are prevented. Then the steel pipe is sent to a two-roller skew rolling mill for skew rolling and piercing, and the control: the total reduction rate is 15 percent, the reduction rate before jacking is 8 percent, the ovality coefficient is 1.15, the perforation speed is 0.42m/s, and the temperature is 1120 ℃, so that a perforated pipe is obtained;

(6) and (5) sending the perforated pipe in the step (5) to a three-roll continuous rolling mill for continuous rolling, and controlling: the total reduction rate is 18 percent, the ovality coefficient is 1.15, the perforation speed is 1m/s, and the temperature is 950 ℃, so as to obtain a continuous rolling pipe;

(7) feeding the continuously rolled pipe in the step (6) into a heating furnace, heating to 900 ℃, feeding the pipe into a sizing mill for sizing, and controlling the sizing rate to be 1m/s to obtain a seamless pipe;

(8) annealing the seamless pipe in the step (7) at the temperature of 900 ℃ for 1h, and cooling to room temperature to obtain a Ti-Al-V-Fe alloy seamless pipe;

the Ti-Al-V-Fe alloy seamless tube comprises the following components: the Ti-Al-V-Fe alloy seamless tube comprises the following components: al: 4.29wt.%, V: 2.61wt.%, Fe: 1.58wt.%, O:0.25 wt.%, balance Ti;

the mechanical properties are shown in table 3 and fig. 7:

TABLE 3

Sample number	Rm/MPa	Rp0.2/MPa	A/%
				1	910.1	840.6	10.26
2	908.2	841.2	11.04
				3	911.7	836.2	10.75
4	910.2	840.2	10.54
				5	916.2	842.3	10.98
6	910.1	846.2	10.53
				Mean value of	910.8	840.9	10.69

Through mechanical property detection, the mechanical properties of each part can meet the requirements, and the obtained seamless pipe has the dimensions of phi 180 multiplied by 12 multiplied by 12542mm (outer diameter multiplied by wall thickness multiplied by length).

As can be seen from the metallographic microstructure of the three embodiments corresponding to FIGS. 2, 3 and 4, the three embodiments are all lamellar structures, and a large number of alpha-phase bundles are staggered with each other.

As can be seen from the mechanical property diagrams of the three embodiments corresponding to fig. 5, fig. 6, and fig. 7, the three embodiments all meet the performance requirements, compared with the prior art, that is: the mechanical properties of the cast ingot obtained by multiple VAR melting and the seamless tube obtained by oblique rolling and piercing after forging (as shown in table 4) are all superior to those of the seamless tube obtained by the prior art in table 4.

The properties of the seamless tube made of Ti-Al-V-Fe alloy by the conventional process are shown in Table 4

TABLE 4

Alloy (I)	Rm/MPa	Rp0.2/MPa	A/%
				Ti-Al-V-Fe	827~965	758~896	6~16

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all the simple modifications, changes and equivalent structural changes of the above embodiments according to the technical spirit of the present invention still belong to the present invention.