CN117696805B - Ti3Al alloy thin bar and preparation method thereof - Google Patents

Abstract

The present invention relates to the technical field of titanium alloy preparation, and in particular to a Ti3Al alloy fine bar and a preparation method thereof. The method comprises the following steps: (a) shaping the Ti3Al alloy ingot in the B2 single-phase region to obtain a square billet, and then performing upsetting and drawing to open the billet to obtain a first billet; (b) then performing upsetting and drawing to open the billet in the B2+α2 two-phase region and the B2+α2+O three-phase region in turn, and then performing drawing in the B2+α2+O three-phase region to obtain a second billet; (c) after chamfering and rounding, performing a fire radial forging at a temperature of 1000-1030°C to obtain a bar billet; (d) performing a fire radial forging at a temperature of 1000-1030°C, and then performing a solid solution aging treatment. The present invention realizes the refinement of the grains in the core of the ingot through the rapid forging process through a combined process of rapid forging and radial forging; in combination with radial forging, the surface structure state of the ingot is improved, and a uniform Ti3Al alloy fine bar is prepared, the cycle is shortened, and the yield rate is improved.

Description

Ti3Al alloy thin rod and preparation method thereof

Technical Field

The invention relates to the technical field of titanium alloy preparation, and in particular to a Ti3Al alloy thin rod and a preparation method thereof.

Background Art

Ti3Al is a kind of Ti-Al based intermetallic compound with an ordered close-packed hexagonal structure. It has high specific strength and is of great significance to aerospace vehicles. The existing process for preparing Ti3Al rods is mainly to produce by upsetting and drawing the blank with a fast forging machine and forming with a fast forging machine. With the rapid development of the aerospace industry, there is a demand for lightweight, high-temperature Ti3Al alloy thin bars. If the existing Ti3Al rod process is used to prepare thin rods, it will lead to problems such as long production cycle, many forging times and low yield rate.

In view of this, the present invention is proposed.

Summary of the invention

An object of the present invention is to provide a method for preparing Ti3Al alloy thin rods to solve the technical problems existing in the prior art such as long production cycle, multiple forging times, and low yield rate.

Another object of the present invention is to provide a Ti3Al alloy thin rod prepared by the above method.

In order to achieve the above-mentioned object of the present invention, the present invention provides a method for preparing a Ti3Al alloy thin rod, comprising the following steps:

(a) The Ti3Al alloy ingot with the required specifications is shaped into a square billet in the temperature range of the B2 single phase region, and then the billet is upset and drawn, and the first billet is repaired after cooling;

(b) subjecting the first blank to upsetting and drawing in the temperature range of the B2+α2 two-phase region and the B2+α2+O three-phase region, and repairing the defects after cooling, and then subjecting the first blank to drawing and repairing the defects after cooling in the temperature range of the B2+α2+O three-phase region, to obtain a second blank;

(c) After the second blank is chamfered and rounded, it is subjected to a fire forging process at a temperature of 1000-1030° C., and then cooled and repaired to obtain a bar blank;

(d) The rod blank is subjected to a fire forging process at a temperature of 1000-1030° C., then cooled to repair scratches, and then subjected to a solid solution aging treatment to obtain the Ti3Al alloy fine rod.

In a specific embodiment of the present invention, in step (a), the total forging ratio of the upset and draw blank is 8-12.

In a specific embodiment of the present invention, in step (b), in the upset and draw blank in each temperature range, the total forging ratio is independently selected from 8 to 12.

In a specific embodiment of the present invention, in step (b), the amount of deformation by stretching is 60% to 80%.

In a specific embodiment of the present invention, in step (c), the fire radial forging includes 4 passes. Further, in the fire radial forging, the pressing amount of a single pass is less than 25 mm, and the deformation amount of a single pass is less than 25%.

In a specific embodiment of the present invention, in step (c), the total deformation amount of the fire radial forging is 50% to 60%.

In a specific embodiment of the present invention, in step (d), the fire radial forging includes 4 passes. Further, in the fire radial forging, the pressing amount of a single pass is less than 25 mm, and the deformation amount of a single pass is less than 25%.

In a specific embodiment of the present invention, in step (d), the total deformation amount of the fire radial forging is 55% to 65%.

In a specific embodiment of the present invention, the temperature of the B2 single-phase region is 1150-1170°C.

In a specific embodiment of the present invention, the temperature of the B2+α2 two-phase region is 1040-1080°C.

In a specific embodiment of the present invention, the temperature of the B2+α2+O three-phase region is 1000-1030°C.

In a specific embodiment of the present invention, in step (a), the upsetting and drawing of the billet comprises: performing an upsetting operation along a first direction at an upsetting temperature to obtain an intermediate billet; and then drawing the intermediate billet along the first direction. Further, the first direction is the length direction of the billet.

In a specific embodiment of the present invention, in step (b), the upsetting and drawing of the blank includes performing an upsetting operation along a first direction at an upsetting temperature to obtain an intermediate blank, and then performing an elongation operation on the intermediate blank along the first direction. Further, the first direction is the length direction of the first blank.

Another aspect of the present invention provides a Ti3Al alloy thin rod prepared by any one of the above-mentioned methods for preparing the Ti3Al alloy thin rod.

In a specific embodiment of the present invention, the diameter of the Ti3Al alloy thin rod is 80-100 mm.

In a specific embodiment of the present invention, in the Ti3Al alloy thin rod, the volume fraction of the equiaxed α2 phase is 5% to 15%, and the size is 3 to 15 μm; the volume fraction of the fine lath α2/O phase is 58% to 65%, and the volume fraction of the matrix B2 phase is 10% to 21%.

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

(1) The present invention adopts a combined process of rapid forging and radial forging, during which the alloy core ingot structure can be fully broken to achieve the refinement of the core grains of the ingot; at the same time, radial forging is used to improve the surface structure of the ingot, and a uniform Ti3Al alloy thin bar is prepared, and the yield rate can be increased to more than 75%;

(2) The Ti3Al alloy thin rod preparation method of the present invention is used to prepare Specifications of Ti3Al alloy thin bars have good organizational uniformity.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

Figure 1 is a high-magnification microstructure diagram of the Ti3Al alloy thin rod prepared in Example 1 of the present invention; wherein (a), (b) and (c) correspond to the high-magnification microstructure diagrams of the edge, 1/2R portion and core portion of the middle of the rod, respectively, and the magnification is 500 times.

DETAILED DESCRIPTION

The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be appreciated by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work, all belong to the scope of protection of the present invention. If the specific conditions are not indicated in the embodiments, they are carried out according to the normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be purchased commercially.

In one aspect, the present invention provides a method for preparing a Ti3Al alloy thin rod, comprising the following steps:

(a) The Ti3Al alloy ingot with the required specifications is shaped into a square billet in the temperature range of the B2 single phase region, and then the billet is upset and drawn, and the first billet is repaired after cooling;

(b) the first blank is subjected to upsetting and drawing in the temperature range of the B2+α2 two-phase region and the B2+α2+O three-phase region, and then repaired after cooling, and then stretched and repaired after cooling in the temperature range of the B2+α2+O three-phase region to obtain a second blank;

(c) After the second blank is chamfered and rounded, it is subjected to a fire forging process at a temperature of 1000-1030° C., and then cooled and repaired to obtain a rod blank;

(d) The rod blank is subjected to a fire forging process at a temperature of 1000-1030°C, cooled to repair the damage, and then subjected to a solid solution aging treatment to obtain a Ti3Al alloy fine rod.

In actual operation, the operations of upsetting, drawing, opening and lengthening in step (a) and step (b) can be performed by a fast forging machine, and the radial forging in step (c) and step (d) can be performed by a radial forging machine.

In the preparation of the Ti3Al alloy thin rod of the present invention, the alloy core ingot structure is first fully broken by the strong hammering force of the hammer of the fast forging machine, and the grain refinement of the core of the ingot is completed; during fast forging, the edge temperature of the ingot is relatively low, and there is a deformation dead zone on the contact surface with the fast forging machine, and there is an unfinished dynamic recrystallization area near the surface of the ingot after drawing. During radial forging, multiple hammers of the radial forging machine strike synchronously and rapidly and continuously, and the surface deformation is large, which can improve the surface structure state of the ingot and improve the yield rate of the rod blank.

During rapid hammering, the billet has almost no expansion during the forging deformation process, and each part deforms evenly, with the characteristics of good stress state, high drawing efficiency, low temperature drop, and high dimensional accuracy. The radial forging process can significantly improve the surface structure of the billet, and can realize one-fire forming and automatic control, thereby improving the yield rate and production efficiency of the billet.

For example, in different embodiments, in step (c), the temperature of a fire forging can be 1000°C, 1010°C, 1020°C, 1030°C or a range consisting of any two thereof; in step (d), the temperature of a fire forging can be 1000°C, 1010°C, 1020°C, 1030°C or a range consisting of any two thereof.

The heat preservation time within each temperature range can be adjusted and selected according to the conventional heat treatment heat preservation time in the art. For example, the heat preservation time at each temperature in step (a) and step (b) can be 300 to 420 minutes, and the heat preservation time at each temperature in step (c) and step (d) can be 60 to 240 minutes.

In a specific embodiment of the present invention, in step (a), the Ti3Al alloy ingot is shaped on a fast forging machine within the temperature range of the B2 single-phase region to obtain a square billet; wherein the side length of the square billet is the same as the diameter of the Ti3Al alloy ingot.

In a specific embodiment of the present invention, in step (a), the total forging ratio of the upsetting and drawing blank is 8-12.

For example, in different embodiments, in step (a), the total forging ratio of the upset and draw blank can be controlled within the range of 8, 9, 10, 11, 12 or any two thereof.

In a specific embodiment of the present invention, in step (b), in the upset and draw blank in each temperature range, the total forging ratio is independently selected from 8 to 12.

For example, in different embodiments, in step (b), in the upset and pull-opening billet in each temperature range of the B2+α2 two-phase region and the B2+α2+O three-phase region, the total forging ratio can be controlled in the range of 8, 9, 10, 11, 12 or any two of them.

In a specific embodiment of the present invention, after the upsetting and drawing of the blank in each temperature range in step (b) is completed, the size of the first blank remains substantially the same.

In a specific embodiment of the present invention, in step (b), the amount of deformation by stretching is 60% to 80%.

For example, in different embodiments, in step (b), the amount of deformation by stretching can be 60%, 65%, 70%, 75%, 80% or a range consisting of any two thereof.

In a specific embodiment of the present invention, in step (c), a fire radial forging includes 4 passes. Further, in a fire radial forging, the pressing amount of a single pass is less than 25 mm, and the deformation amount of a single pass is less than 25%.

For example, in different embodiments, in step (c), in a fire radial forging, the pressing amount of a single pass can be 25mm, 20mm, 15mm, 10mm, 5mm or a range consisting of any two thereof, and the deformation amount of a single pass can be 25%, 20%, 15%, 10%, 5% or a range consisting of any two thereof. Controlling the pressing amount and deformation amount of a single pass in a fire radial forging within the above range helps to improve the surface structure of the bar blank during the radial forging process. The pressing amount and deformation amount of each pass in a fire radial forging can be the same or different, and the pressing amount and deformation amount of each pass respectively meet the above conditions, and each pass as a whole can achieve the total deformation requirement of a fire radial forging.

In a specific embodiment of the present invention, in step (c), the total deformation amount of a fire radial forging is 50% to 60%.

For example, in different embodiments, in step (c), the total deformation of the fire radial forging can be 50%, 52%, 54%, 55%, 56%, 58%, 60% or any two thereof. The total deformation of the fire radial forging within the above range can further ensure that the surface of the rod blank has sufficient deformation during the radial forging process to improve the microstructure of the surface of the rod blank.

In a specific embodiment of the present invention, in step (d), a fire radial forging includes 4 passes. Further, in a fire radial forging, the pressing amount of a single pass is less than 25 mm, and the deformation amount of a single pass is less than 25%.

For example, in different embodiments, in step (d), in a fire radial forging, the pressing amount of a single pass can be 25mm, 20mm, 15mm, 10mm, 5mm or a range consisting of any two thereof, and the deformation amount of a single pass can be 25%, 20%, 15%, 10%, 5% or a range consisting of any two thereof. Preferably, in the fire radial forging of step (d), the pressing amount of a single pass is <20mm, preferably ≤15mm. Controlling the pressing amount and deformation amount of a single pass in a fire radial forging within the above range is helpful to improve the surface structure of the bar blank during radial forging. The pressing amount and deformation amount of each pass in a fire radial forging can be the same or different, as long as the pressing amount and deformation amount of each pass meet the above conditions respectively, and each pass as a whole can achieve the total deformation requirement of a fire radial forging.

In a specific embodiment of the present invention, in step (d), the total deformation amount of a fire radial forging is 55% to 65%.

For example, in different embodiments, in step (d), the total deformation of the fire radial forging can be 55%, 56%, 58%, 60%, 62%, 64%, 65% or any two thereof. The total deformation of the fire radial forging within the above range can further ensure that the surface of the rod blank has sufficient deformation during the radial forging process to improve the microstructure of the surface of the rod blank.

In a specific embodiment of the present invention, the temperature of the B2 single-phase region is 1150-1170°C.

For example, in different embodiments, the temperature of the B2 single-phase region may be 1150° C., 1155° C., 1160° C., 1165° C., 1170° C., or a range consisting of any two thereof.

In a specific embodiment of the present invention, the temperature of the B2+α2 two-phase region is 1040-1080°C.

For example, in different embodiments, the temperature of the B2+α2 two-phase region can be 1040°C, 1050°C, 1060°C, 1070°C, 1080°C or a range consisting of any two thereof.

In a specific embodiment of the present invention, the temperature of the B2+α2+O three-phase region is 1000-1030°C.

For example, in different embodiments, the temperature of the B2+α2+O three-phase region may be 1000°C, 1010°C, 1020°C, 1030°C, or a range consisting of any two of them.

In a specific embodiment of the present invention, in step (a), the upsetting and drawing of the billet comprises: performing an upsetting operation along a first direction at an upsetting temperature to obtain an intermediate billet; and then drawing the intermediate billet along the first direction. Further, the first direction is the length direction of the billet.

In a specific embodiment of the present invention, in step (b), the upsetting and drawing of the blank includes performing an upsetting operation along a first direction at an upsetting temperature to obtain an intermediate blank, and then drawing the intermediate blank along the first direction. Further, the first direction is the length direction of the first blank.

In a specific embodiment of the present invention, in step (b), when the drawing is performed within the temperature range of the B2+α2+O three-phase region, the direction of the drawing is the length direction of the Ti3Al alloy.

In actual operation, chamfering and rounding can be carried out on a fast forging machine.

In a specific embodiment of the present invention, in step (d), the solution aging treatment includes: solution treatment at 1000°C for 3 hours, followed by oil quenching; and aging treatment at 800°C for 24 hours, followed by air cooling.

The Ti3Al alloy of the present invention can provide an efficient preparation process route for Ti-23Al-17Nb alloy thin rods.

Another aspect of the present invention provides a Ti3Al alloy thin rod prepared by any one of the above-mentioned methods for preparing the Ti3Al alloy thin rod.

In a specific embodiment of the present invention, the diameter of the Ti3Al alloy thin rod is 80-100 mm.

For example, in different embodiments, the diameter of the Ti3Al alloy thin rod can be 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, or a range consisting of any two of them.

In a specific embodiment of the present invention, in the Ti3Al alloy thin rod, the volume fraction of the equiaxed α2/O phase is 5% to 15%, and the size is 3 to 15 μm; the volume fraction of the fine lath α2/O phase is 58% to 65%, and the volume fraction of the matrix B2 phase is 10% to 21%.

For example, in different embodiments, in the Ti3Al alloy thin rod, the volume fraction of the equiaxed α2/O phase can be 5%, 8%, 10%, 12%, 15% or a range consisting of any two of them, and the size of the equiaxed α2/O phase can be 3μm, 5μm, 8μm, 10μm, 12μm, 15μm or a range consisting of any two of them; the volume fraction of the fine lath α2/O phase can be 58%, 60%, 61%, 62%, 63%, 64%, 65% or a range consisting of any two of them; the volume fraction of the matrix B2 phase can be 10%, 12%, 15%, 18%, 20%, 21% or a range consisting of any two of them.

Example 1

This embodiment provides a method for preparing a Ti3Al alloy thin rod, comprising the following steps:

(1) Select the size The Ti3Al alloy ingot was heated to 1160℃ and kept warm for 380min. The ingot was shaped to 380×380×760mm on a fast forging machine, and then upset and drawn at 1160℃. The ingot was upset and drawn three times to a size of 380×380×760mm, and the total forging ratio was controlled at 10. After forging, it was air-cooled to repair damage.

(2) The billet with a size of 380×380×760 mm obtained in step (1) is kept at 1060° C. for 380 min, and then upset and draw the billet on a fast forging machine. The billet is upset and drawn three times to a size of 380×380×760 mm, and the total forging ratio is controlled to 10. After forging, the billet is air-cooled and repaired.

(3) The blank with a size of 380×380×760 mm obtained in step (2) is kept at 1010° C. for 380 min, and then upset and draw the blank on a fast forging machine. The blank is upset and drawn three times to a size of 380×380×760 mm, and the total forging ratio is controlled to 10. After forging, the blank is air-cooled and repaired.

(4) The billet with a size of 380×380×760 mm obtained in step (3) is kept at 1010° C. for 380 min, and then stretched on a fast forging machine to a size of 210×210×2240 mm. After forging, it is air-cooled, repaired, and divided into two equal parts along the length.

(5) The blank with the size of 210×210×1120 mm obtained in step (4) is chamfered and rounded on a fast forging machine until Repair the damage after air cooling.

(6) The size obtained in step (5) is After the billet was kept at 1010℃ for 190min, it was forged in four passes on a forging machine. The reductions in each pass were 20mm, 20mm, 15mm, and 10mm respectively. After forging, air cool and repair the damage, and divide it into two equal parts along the length.

(7) The size obtained in step (6) is After the billet was kept at 1010℃ for 125min, it was forged in four passes on a forging machine. The reductions in each pass were 13mm, 12mm, 11mm, and 9mm respectively. After forging, cool in air to repair damage.

(8) subjecting the blank obtained in step (7) to a solution aging treatment, and then conducting a performance test and evaluation; wherein the solution aging treatment comprises: solution treatment at 1000° C. for 3 h, followed by oil quenching; and aging treatment at 800° C. for 24 h, followed by air cooling.

Example 2

This embodiment provides a method for preparing a Ti3Al alloy thin rod, comprising the following steps:

(1) Select the size The Ti3Al alloy ingot was heated to 1150℃ and kept warm for 380min. The ingot was shaped to 380×380×760mm on a fast forging machine, and then upset and drawn at 1150℃. The ingot was upset and drawn three times to a size of 380×380×760mm, and the total forging ratio was controlled at 8. After forging, it was air-cooled to repair damage.

(2) The billet with a size of 380×380×760 mm obtained in step (1) is kept at 1050° C. for 380 min, and then upset and draw the billet on a fast forging machine. The billet is upset and drawn three times to a size of 380×380×760 mm, and the total forging ratio is controlled to 8. After forging, the billet is air-cooled and repaired.

(3) The billet with a size of 380×380×760 mm obtained in step (2) is kept at 1000° C. for 380 min, and then upset and draw the billet on a fast forging machine. The billet is upset and drawn three times to a size of 380×380×760 mm, and the total forging ratio is controlled to 8. After forging, the billet is air-cooled and repaired.

(4) The billet with a size of 380×380×760 mm obtained in step (3) is kept at 1000° C. for 380 min, and then stretched on a fast forging machine to a size of 210×210×2240 mm. After forging, it is air-cooled, repaired, and divided into two equal parts along the length.

(5) The blank with the size of 210×210×1120 mm obtained in step (4) is chamfered and rounded on a fast forging machine until Repair the damage after air cooling.

(6) The size obtained in step (5) is The billet was kept at 1000℃ for 190min, and then forged in four passes on a forging machine. The reductions in each pass were 20mm, 20mm, 15mm, and 10mm respectively. After forging, air cool and repair the damage, and divide it into two equal parts along the length.

(7) The size obtained in step (6) is The billet was kept at 1000℃ for 125min, and then forged in four passes on a forging machine. The reductions in each pass were 13mm, 12mm, 11mm, and 9mm respectively. After forging, cool in air to repair damage.

(8) subjecting the blank obtained in step (7) to a solution aging treatment, and then conducting a performance test and evaluation; wherein the solution aging treatment comprises: solution treatment at 1000° C. for 3 h, followed by oil quenching; and aging treatment at 800° C. for 24 h, followed by air cooling.

Example 3

This embodiment provides a method for preparing a Ti3Al alloy thin rod, comprising the following steps:

(1) Select the size The Ti3Al alloy ingot was heated to 1170℃ and kept warm for 380min. The ingot was shaped to 380×380×760mm on a fast forging machine, and then upset and drawn at 1170℃. It was upset and drawn three times to a size of 380×380×760mm, and the total forging ratio was controlled at 12. After forging, it was air-cooled to repair damage.

(2) The blank with a size of 380×380×760 mm obtained in step (1) was kept at 1070° C. for 380 min, and then upset and drawn on a fast forging machine to open the blank. The blank was upset and drawn three times to a size of 380×380×760 mm, and the total forging ratio was controlled to 12. After forging, the blank was air-cooled and repaired.

(3) The blank with a size of 380×380×760 mm obtained in step (2) is kept at 1020° C. for 380 min, and then upset and draw is performed on a fast forging machine to open the blank. The blank is upset and drawn three times to a size of 380×380×760 mm, and the total forging ratio is controlled to 12. After forging, the blank is air-cooled and repaired.

(4) The billet with a size of 380×380×760 mm obtained in step (3) is kept at 1020° C. for 380 min, and then stretched on a fast forging machine to a size of 210×210×2240 mm. After forging, it is air-cooled, repaired, and divided into two equal parts along the length.

(5) The blank with the size of 210×210×1120 mm obtained in step (4) is chamfered and rounded on a fast forging machine until Repair the damage after air cooling.

(6) The size obtained in step (5) is After the billet was kept at 1020℃ for 190min, it was forged in four passes on a forging machine. The reductions in each pass were 20mm, 20mm, 15mm, and 10mm respectively. After forging, air cool and repair the damage, and divide it into two equal parts along the length.

(7) The size obtained in step (6) is After the billet was kept at 1020℃ for 125min, it was forged in four passes on a forging machine. The reductions in each pass were 13mm, 12mm, 11mm, and 9mm respectively. After forging, cool in air to repair damage.

(8) subjecting the blank obtained in step (7) to a solution aging treatment, and then conducting a performance test and evaluation; wherein the solution aging treatment comprises: solution treatment at 1000° C. for 3 h, followed by oil quenching; and aging treatment at 800° C. for 24 h, followed by air cooling.

Example 4

This embodiment provides a method for preparing Ti3Al alloy thin rods with reference to Embodiment 1, the only difference being that the reduction amount per pass in the radial forging of step (6) and step (7) is different.

In step (6), in the four-pass radial forging with a single fire, the reduction amounts of each pass are 25 mm, 25 mm, 10 mm, and 5 mm respectively;

In step (7), in the four-pass radial forging in a single fire, the reduction amount of each pass is 20 mm, 15 mm, 5 mm, and 5 mm respectively.

Comparative Example 1

Comparative Example 1 provides a method for preparing a Ti3Al alloy rod, comprising the following steps:

(1) Select the size The Ti3Al alloy ingot was heated to 1160℃ and kept warm for 380min. The ingot was shaped to 380×380×760mm on a fast forging machine, and then upset and drawn at 1160℃. The ingot was upset and drawn three times to a size of 380×380×760mm, and the total forging ratio was controlled at 10. After forging, it was air-cooled to repair damage.

(2) The blank with a size of 380×380×760 mm obtained in step (1) was kept at 1110° C. for 380 min, and then upset and drawn on a fast forging machine to open the blank. The blank was upset and drawn three times to a size of 380×380×760 mm, and the total forging ratio was controlled to 10. After forging, the blank was air-cooled and repaired.

(3) The billet with a size of 380×380×760 mm obtained in step (2) is kept at 1060° C. for 380 min, and then upset and draw the billet on a fast forging machine. The billet is upset and drawn three times to a size of 380×380×760 mm, and the total forging ratio is controlled to 10. After forging, the billet is air-cooled and repaired.

(4) The blank with a size of 380×380×760 mm obtained in step (3) is kept at 1010° C. for 380 min, and then upset and draw is performed on a fast forging machine to open the blank. The blank is upset and drawn three times to a size of 380×380×760 mm, and the total forging ratio is controlled to 10. After forging, the blank is air-cooled and repaired.

(5) The billet with a size of 380×380×760 mm obtained in step (4) is kept at 1010° C. for 380 min, and then stretched on a fast forging machine to a size of 210×210×2240 mm. After forging, it is air-cooled, repaired, and divided into two equal parts along the length.

(6) The billet with a size of 210×210×1120 mm obtained in step (5) is kept at 1010° C. for 380 min, and then stretched on a fast forging machine to a size of 120×120×3430 mm. After forging, it is air-cooled, repaired, and divided into two equal parts along the length.

(7) The blank with a size of 120×120×1710 mm obtained in step (6) is chamfered and rounded on a fast forging machine until Repair the damage after air cooling.

(8) subjecting the blank obtained in step (7) to a solution aging treatment, and then conducting a performance test and evaluation; wherein the solution aging treatment comprises: solution treatment at 1000° C. for 3 h, followed by oil quenching; and aging treatment at 800° C. for 24 h, followed by air cooling.

Experimental example

The microstructure of the Ti3Al alloy thin rod prepared in Example 1 was tested, and the test results are shown in Figure 1. As can be seen from the figure, the uniformity of the edge, 1/2R portion and core of the Ti3Al alloy thin rod prepared by the present invention is good, and the α2 phase is evenly distributed in the rod.

The grain size (test standard reference GB/T6494-2017) and volume fraction of different phases (tested using Image plus software) of the thin rods of Examples 1 to 4 and Comparative Example 1 were tested, and the test results are shown in Table 1.

Table 1 Test results of thin bars prepared in different embodiments and comparative examples

The room temperature and 900°C mechanical properties of the Ti3Al alloy thin bars obtained by processing Examples 1 to 4 and Comparative Example 1 were tested (the test standards refer to GB/T 228.1 and GB/T 228.2). The test results are shown in Table 2.

Table 2 Performance test results of different thin bars

From the above test results, it can be seen that the Ti3Al alloy prepared by the present invention The performance of the fine-sized bars is improved compared to the existing rapid forging process, the yield strength at 900°C is greater than 150MPa, and the surface quality of the bars is good.

The yield rates of the preparation methods of Examples 1 to 4 of the present invention and the yield rate of the preparation method of Comparative Example 1 were calculated, and the results are shown in Table 3.

Table 3 Yield rate of different preparation methods

serial number Yield rate/% Example 1 76 Example 2 75 Example 3 77 Example 4 75 Comparative Example 1 69

From the above results, it can be seen that the preparation method of the Ti3Al alloy thin rod of the present invention not only has good surface quality of the thin rod, but also has improved performance. Compared with the traditional fast forging process route, the preparation method of the present invention is more suitable for preparing thin rods, which can significantly shorten the process production cycle and improve the yield rate.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims (14)

1. The preparation method of the Ti3Al alloy thin bar is characterized by comprising the following steps of:

   (a) Will be Shaping a Ti3Al alloy cast ingot with the specification in the temperature range of the B2 single-phase region to obtain a square billet, upsetting, drawing and cogging, cooling and repairing to obtain a first blank;

   (b) Sequentially upsetting, drawing, cooling and repairing the first blank in the temperature ranges of a B2+alpha 2 two-phase region and a B2+alpha 2+O three-phase region, and drawing and cooling and repairing the first blank in the temperature range of the B2+alpha 2+O three-phase region to obtain a second blank;

   (c) Chamfering and rounding the second blank, performing hot diameter forging at the temperature of 1000-1030 ℃, and cooling and repairing wounds to obtain a bar blank;

   (d) Performing hot diameter forging on the bar blank at the temperature of 1000-1030 ℃, cooling to repair the damage, and performing solid solution aging treatment to obtain the Ti3Al alloy thin bar;

   In the step (c), in the first-pass forging, the single-pass pressing amount is less than 25mm, and the single-pass deformation amount is less than 25%;

   In the step (c), the total deformation of the first-fire radial forging is 50-60%.
2. 2. The method for producing a Ti3Al alloy thin rod according to claim 1, wherein in the step (a), the total forging ratio of the upsetting-drawing bloom is 8 to 12.
3. 3. The method of producing a Ti3Al alloy thin rod according to claim 1, wherein in step (b), the total forging ratio in the upsetting-drawing bloom in each temperature range is independently selected from 8 to 12.
4. 4. The method for producing a Ti3Al alloy thin rod according to claim 1, wherein in the step (b), the elongation deformation amount is 60% to 80%.
5. 5. The method of producing a Ti3Al alloy thin rod according to claim 1, wherein in step (c), the one-hot forging includes 4 passes.
6. 6. The method of producing a Ti3Al alloy thin rod according to claim 1, wherein in step (d), the one-hot forging includes 4 passes.
7. 7. The method of producing a Ti3Al alloy thin rod according to claim 1, wherein in the step (d), the single pass pressing amount is less than 25mm and the single pass deformation amount is less than 25% in the one-pass forging.
8. 8. The method of producing a Ti3Al alloy thin rod according to claim 1, wherein in the step (d), the total deformation amount of the one-hot diameter forging is 55% to 65%.
9. 9. The method of producing a Ti3Al alloy thin rod according to claim 1, characterized by having at least one of the following features:

   (1) The temperature of the B2 single-phase region is 1150-1170 ℃;

   (2) The temperature of the B2+alpha 2 two-phase region is 1040-1080 ℃;

   (3) The temperature of the B2+alpha 2+O three-phase region is 1000-1030 ℃.
10. 10. The method for producing a Ti3Al alloy thin rod according to claim 1, wherein in the step (a), the upsetting-drawing cogging comprises: upsetting operation is carried out along a first direction at upsetting temperature, so that an intermediate blank is obtained; then, the intermediate blank is subjected to drawing operation along a first direction;

    the first direction is the length direction of the square billet.
11. 11. The method for producing a Ti3Al alloy thin rod according to claim 1, wherein in the step (b), the upsetting-drawing cogging comprises upsetting in a first direction at a upsetting temperature to obtain an intermediate billet; then, the intermediate blank is subjected to drawing operation along a first direction;

    the first direction is a length direction of the first blank.
12. 12. A Ti3Al alloy thin rod produced by the production method of the Ti3Al alloy thin rod according to any one of claims 1 to 11.
13. 13. The Ti3Al alloy thin rod according to claim 12, wherein the Ti3Al alloy thin rod has a diameter of 80 to 100mm.
14. 14. The Ti3Al alloy thin rod according to claim 13, wherein in the Ti3Al alloy thin rod, the volume fraction of the equiaxed α2 phase is 5% -15%, and the size is 3-15 μm; the volume fraction of the alpha 2/O phase of the fine lath is 58% -65%, and the volume fraction of the B2 phase of the matrix is 10% -21%.