Preparation method of high-toughness trace boron modified Ti-Al-V-Fe alloy plate

Abstract

The invention relates to a preparation method of a high-toughness trace boron modified Ti-Al-V-Fe alloy plate. The preparation method is characterized by comprising the following steps: 1) preparing materials; 2) mixing the materials, briquetting, welding an electrode, and smelting twice in a vacuum consumable electrode electric arc furnace to obtain a cast ingot; (3) cogging is carried out at the temperature of 930-1120 DEG C, intermediate forging and final forging are carried out, and a forged blank is obtained; (4) heating to 980-1000 DEG C, keeping the temperature for 1-2 hours, feeding into a rolling mill, and carrying out hot rolling for 6 passes, so as to obtain a hot-rolled plate; 5, heat preservation is conducted for 1-2 h at the temperature of 770-790 DEG C, annealing is conducted, grinding, acid pickling, straightening and shearing are conducted after cooling is conducted to the room temperature, and the trace boron modified Ti-Al-V-Fe alloy sheet is obtained.The prepared sheet is fine in grain and uniform in structure and has the excellent room temperature (larger than or equal to 1150 MPa), the excellent high-temperature tensile strength (larger than or equal to 645 MPa) and the excellent ductility (larger than or equal to 12%), and the strength and plasticity matching and machinability are obviously improved.

Description

Technical Field

[0001] The invention relates to a method for preparing a high-strength and tough trace-boron modified Ti-Al-V-Fe alloy plate, belonging to the technical field of titanium alloy material rolling. Background Art

[0002] Ti-Al-V-Fe alloy is an α+β dual-phase titanium alloy. Compared with the traditional Ti-6Al-4V alloy, the two have comparable mechanical properties, but the former is more machinable than the latter. At the same time, Ti-Al-V-Fe alloy uses cheap Fe to replace part of the expensive V as a β-stabilizing element, which reduces the cost of raw materials and can be processed into products in various forms such as plates / rods / tubes, with broad application prospects. However, the Ti-Al-V-Fe alloy sheet prepared by the prior art still has problems such as coarse grains, uneven internal structure, low strength and plasticity during actual application, especially poor high-temperature mechanical properties, which greatly limits its application in harsh engineering environments. Therefore, it is necessary to improve the prior art. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the present invention provides a method for preparing a high-strength and tough trace-boron-modified Ti-Al-V-Fe alloy plate.

[0004] The present invention is achieved through the following technical solutions: A method for preparing a high-strength and tough trace-boron-modified Ti-Al-V-Fe alloy plate, characterized by comprising the following steps: (1) Prepare the ingredients in the following mass ratio: Aluminum-vanadium master alloy 4.0~4.5 wt.% Aluminum beans 2.1~2.6 wt.%, Titanium-iron master alloy 1.9~2.6 wt.% Titanium dioxide 0.45~0.5 wt.%, Titanium diboride particles 0.11~0.22 wt.%, Titanium sponge balance, The sum of the above components is 100 wt.%; (2) the materials of step (1) are mixed and briquette-pressed, and welded into electrodes, which are smelted in a vacuum consumable electrode arc furnace to obtain a primary ingot, which are then remelted to obtain a secondary ingot. The vacuum degree during the smelting process is 0.10-0.18 Pa, the arc voltage is 30-32 V, the arc current is 3.55-3.66 kA, and the arc stabilization current is 3.55-3.69 kA; (3) The ingot of step (2) is forged by a three-pier three-draw process, the blank is opened at 1080-1120° C., then the intermediate forging is performed at 1030-1070° C., and finally the finished product is forged at 930-970° C. After the forging is completed, the ingot is ground to obtain a forged blank; (4) spraying an appropriate amount of anti-oxidation liquid on the surface of the forging blank in step (3), sending it into a heating furnace, heating it to 980-1000°C at a heating rate of 4-6°C / min, keeping it at this temperature for 1-2h, and then sending it into a rolling mill for hot rolling, with the starting rolling temperature being 900-920°C, hot rolling being performed in 6 passes, with the cumulative deformation controlled at 75%-85%, and the final rolling temperature being controlled at 860-880°C. After taking it out, cooling it in air to room temperature to obtain a hot-rolled plate; (5) The hot-rolled sheet of step (4) is fed into an annealing furnace and annealed at 770-790° C. for 1-2 h. During the annealing process, argon gas with a purity of 99.99% is continuously introduced for protection. After the annealing is completed, the sheet is taken out and cooled to room temperature in air. After grinding, pickling, straightening and shearing, a trace boron-modified Ti-Al-V-Fe alloy sheet having the following composition is obtained: Al: 3.5wt.%-4.5wt.%, V: 2.0wt.%-3.0wt.%, Fe: 1.2wt.%-1.8wt.%, O: 0.2wt.%-0.3wt.%, B: 0.04wt.%-0.08wt.%, C: ≤0.08wt.%, N: ≤0.03wt.%, H: ≤0.015wt.%, and the rest is Ti.

[0005] The mass ratio of Al:V of the aluminum-vanadium master alloy in step (1) is 2:3; the purity of aluminum beans is ≥99.84%; the mass ratio of Ti:Fe of the titanium-iron master alloy is 2:1; the purity of titanium dioxide is ≥99.82%; the purity of titanium diboride particles is ≥99.57%; and the purity of titanium sponge is ≥99.9%.

[0006] In the six hot rolling passes of step (4), the deformation rate of each pass is controlled to be 20-26%, 18-24%, 22-27%, 15-24%, 13-24%, and 15-22% in sequence.

[0007] The present invention has the following advantages and beneficial effects:

[0008] The micro-boron modified Ti-Al-V-Fe alloy plate prepared by the above technical scheme not only has fine grains and uniform internal structure, but also has excellent room temperature and high temperature mechanical properties. By adding a trace amount of boron to the alloy for modification, its cast structure is significantly refined, the machinability of the alloy is improved, the deformation uniformity during hot working is improved, and the problems of coarse grains and uneven structure of the Ti-Al-V-Fe alloy plate are solved. The prepared micro-boron modified Ti-Al-V-Fe alloy plate has excellent room temperature tensile strength (≥1150MPa) and elongation (≥12%), which exceeds the ASTM B265-20a standard (tensile strength ≥895MPa, elongation ≥10%); at the same time, it also has excellent high temperature tensile strength (≥645MPa) and elongation (≥20%), and the strong plasticity and machinability are significantly improved, which can meet the needs of harsh engineering environments and has broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is the cast metallographic structure diagram of the alloy with a boron content of 0.08wt.%.

[0010] Figure 2 This is the metallographic structure diagram of the plate obtained in Example 1 of the present invention.

[0011] Figure 3 This is the metallographic structure diagram of the plate obtained in Example 2 of the present invention.

[0012] Figure 4 This is the metallographic structure diagram of the plate obtained in Example 3 of the present invention.

[0013] Figure 5 Graph showing room temperature tensile properties of the plates obtained in Examples 1, 2, and 3 of the present invention.

[0014] Figure 6 This is a diagram of the high temperature tensile properties of the plates obtained in Examples 1, 2, and 3 of the present invention. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with specific implementation methods, but the protection scope of the present invention is not limited to the above contents. Example 1

[0016] A method for preparing a high-strength and tough trace-boron-modified Ti-Al-V-Fe alloy plate, characterized by comprising the following steps: (1) Prepare the ingredients in the following mass ratio: Aluminum-vanadium master alloy 4.07 wt.%, Aluminum beans 2.53 wt.%, Titanium-iron master alloy 1.94wt.%, Titanium dioxide 0.46 wt.%, Titanium diboride particles 0.11 wt.%, Titanium sponge 90.89wt.%; (2) The materials of step (1) are mixed and pressed into blocks, and welded into electrodes, which are smelted in a vacuum consumable electrode arc furnace to obtain a primary ingot, and then remelted to obtain a secondary ingot. During the smelting process, the vacuum degree is controlled to be 0.15 Pa, the arc voltage is 31 V, the arc current is 3.6 kA, and the arc stabilization current is 3.6 kA; (3) The ingot of step (2) is forged by a three-pier three-draw process, the blank is opened at 1100° C., then the intermediate forging is performed at 1050° C., and finally the finished product is forged at 950° C. After the forging is completed, the ingot is ground to obtain a forged blank; (4) spraying an appropriate amount of anti-oxidation liquid on the surface of the forging billet in step (3), sending it into a heating furnace, heating it to 980°C at a heating rate of 5°C / min, keeping it at that temperature for 1 hour, and then sending it into a rolling mill for hot rolling, controlling the start rolling temperature to 900°C, and hot rolling it in 6 passes, with the deformation rates of each pass being 25%, 23.3%, 26.1%, 23.5%, 23.1%, and 20% respectively, and the cumulative deformation amount being 80%, controlling the final rolling temperature to 860°C, and cooling it in air to room temperature after taking it out to obtain a hot-rolled plate; (5) The plate obtained in step (4) is fed into an annealing furnace and annealed at 770°C for 1 hour. During the annealing process, argon gas with a purity of 99.99% is continuously introduced for protection. After the annealing is completed, the plate is taken out, cooled to room temperature in air, and then ground, pickled, straightened, and sheared to obtain a trace boron-modified Ti-Al-V-Fe alloy plate having the following composition: Al: 4.12wt.%, V: 2.44wt.%, Fe: 1.29wt.%, O: 0.23wt.%, B: 0.04wt.%, C: ≤0.08wt.%, N: ≤0.03wt.%, H: ≤0.015wt.%, and the rest is Ti.

[0017] Room temperature and high temperature mechanical properties are shown in Table 1: Table 1 Room temperature and high temperature tensile properties of the obtained sheets Example 2

[0018] A method for preparing a high-strength and tough trace-boron-modified Ti-Al-V-Fe alloy plate, characterized by comprising the following steps: (1) Prepare the ingredients in the following mass ratio: Aluminum-vanadium master alloy 4.45 wt.%, Aluminum beans 2.55 wt.%, Titanium-iron master alloy 2.6 wt.%, Titanium dioxide 0.46 wt.%, Titanium diboride particles 0.16 wt.%, Titanium sponge 89.78wt.% (2) The materials in step (1) are mixed and pressed into blocks, and then welded into electrodes, which are smelted in a vacuum consumable electrode arc furnace to obtain a primary ingot, which are then remelted to obtain a secondary ingot. During the smelting process, the vacuum degree is controlled to be 0.15 Pa, the arc voltage is 31 V, the arc current is 3.6 kA, and the arc stabilization current is 3.6 kA; (3) The ingot of step (2) is forged by a three-pier three-draw process, and the blank is opened at 1100° C.; then the intermediate forging is performed at 1050° C.; finally, the finished product is forged at 950° C., and after the forging is completed, the finished product is ground to obtain a forged blank; (4) spraying an appropriate amount of anti-oxidation liquid on the surface of the forging billet in step (3), sending it into a heating furnace and heating it to 990°C at a heating rate of 5°C / min, and keeping it at this temperature for 1 hour; then sending it into a rolling mill for hot rolling, controlling the start rolling temperature to 910°C, and hot rolling in 6 passes, with the deformation rates of each pass being 25%, 23.3%, 26.1%, 23.5%, 23.1%, and 20% respectively, and the cumulative deformation amount being 80%, controlling the final rolling temperature to 870°C, and cooling it to room temperature in air after taking it out to obtain a hot-rolled plate; (5) The hot-rolled sheet of step (4) is fed into an annealing furnace and annealed at 780° C. for 1 to 2 h. During the annealing process, argon gas with a purity of 99.99% is continuously introduced for protection. After the annealing is completed, the sheet is taken out, cooled to room temperature in air, and then ground, pickled, straightened, and sheared to obtain a trace boron-modified Ti-Al-V-Fe alloy sheet having the following composition: Al: 4.29wt.%, V: 2.67wt.%, Fe: 1.73wt.%, O: 0.23wt.%, B: 0.06wt.%, C: ≤0.08wt.%, N: ≤0.03wt.%, H: ≤0.015wt.%, and the rest is Ti.

[0019] Room temperature and high temperature mechanical properties are shown in Table 2: Table 2 Room temperature and high temperature tensile properties of the obtained plates Example 3

[0020] A method for preparing a high-strength and tough trace-boron-modified Ti-Al-V-Fe alloy plate, characterized by comprising the following steps: (1) Prepare the ingredients in the following mass ratio: Aluminum-vanadium master alloy 4.35 wt.%, Aluminum beans 2.47 wt.%, Titanium-iron master alloy 2.45 wt.%, Titanium dioxide 0.48 wt.%, Titanium diboride particles 0.22 wt.%, Titanium sponge 90.04 wt.%; (2) The materials in step (1) are mixed and pressed into blocks, and then welded into electrodes, which are smelted in a vacuum consumable electrode arc furnace to obtain a primary ingot, which are then remelted to obtain a secondary ingot. During the smelting process, the vacuum degree is controlled to be 0.15 Pa, the arc voltage is 31 V, the arc current is 3.6 kA, and the arc stabilization current is 3.6 kA; (3) The ingot of step (2) is forged by a three-pier three-draw process, and the blank is opened at 1100° C.; then the intermediate forging is performed at 1050° C.; finally, the finished product is forged at 950° C., and after the forging is completed, the finished product is ground to obtain a forged blank; (4) spraying an appropriate amount of anti-oxidation liquid on the surface of the forging billet in step (3), sending it into a heating furnace and heating it to 1000°C at a heating rate of 5°C / min, and keeping it at this temperature for 1 hour; then sending it into a rolling mill for hot rolling, controlling the start rolling temperature to 920°C, and hot rolling in 6 passes, with the deformation rates of each pass being 25%, 23.3%, 26.1%, 23.5%, 23.1%, and 20% respectively, and the cumulative deformation amount being 80%, controlling the final rolling temperature to 880°C, and cooling it to room temperature in air after taking it out to obtain a hot-rolled plate; (5) The hot-rolled sheet of step (4) is fed into an annealing furnace and annealed at 790° C. for 1 to 2 h. During the annealing process, argon gas with a purity of 99.99% is continuously introduced for protection. After the annealing is completed, the sheet is taken out, cooled to room temperature in air, and then ground, pickled, straightened, and sheared to obtain a trace boron-modified Ti-Al-V-Fe alloy sheet having the following composition: Al: 4.17wt.%, V: 2.61wt.%, Fe: 1.63wt.%, O: 0.24wt.%, B: 0.08wt.%, C: ≤0.08wt.%, N: ≤0.03wt.%, H: ≤0.015wt.%, and the rest is Ti.

[0021] Room temperature and high temperature mechanical properties are shown in Table 3: Table 3 Room temperature and high temperature tensile properties of the obtained plates

[0022] Figure 1 The metallographic structure of the alloy cast with a boron content of 0.08wt.% is a basket structure composed of fine α+β clusters arranged alternately and interwoven with each other. The metallographic structures of the plates prepared in Examples 1, 2, and 3 correspond to Figure 2 , Figure 3 , Figure 4All examples show fine grains and uniform microstructure, accompanied by the precipitation of TiB whiskers, and their length direction is consistent with the rolling direction.

[0023] The mechanical properties of the plates obtained in Examples 1, 2 and 3 are shown in Tables 1, 2 and 3. The average values ​​of the room temperature tensile properties correspond to Figure 5 , the average value of high temperature tensile properties corresponds to Figure 6 . It can be seen from the results that the three embodiments all have excellent room temperature and high temperature comprehensive mechanical properties. The tensile strength Rm≥1150MPa and the elongation A≥12% at room temperature are better than the ASTM B265-20a standard (tensile strength Rm≥895MPa, elongation A≥10%); at the same time, the tensile strength Rm≥645MPa and the elongation A≥20% at high temperature. Under room temperature and high temperature tensile conditions, the sheet has excellent strength and plastic toughness matching, and a high-strength and tough trace-boron modified Ti-Al-V-Fe alloy sheet is obtained.

[0024] The above description is only a preferred implementation manner of the present invention, but the protection scope of the present invention is not limited thereto, and any modification and replacement based on the technical solution and inventive concept provided by the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a high-strength and tough trace-boron-modified Ti-Al-V-Fe alloy sheet, characterized in that The following steps are included: (1) Prepare the ingredients in the following mass ratio: Aluminum-vanadium master alloy 4.0~4.5 wt.% Aluminum beans 2.1~2.6 wt.%, Titanium-iron master alloy 1.9~2.6 wt.% Titanium dioxide 0.45~0.5 wt.%, Titanium diboride particles 0.11~0.22 wt.%, Titanium sponge balance, The sum of the above components is 100 wt.%; (2) the materials of step (1) are mixed and briquette-pressed, and welded into electrodes, which are smelted in a vacuum consumable electrode arc furnace to obtain a primary ingot, which are then remelted to obtain a secondary ingot. The vacuum degree during the smelting process is 0.10-0.18 Pa, the arc voltage is 30-32 V, the arc current is 3.55-3.66 kA, and the arc stabilization current is 3.55-3.69 kA; (3) The ingot of step (2) is forged by a three-pier three-draw process, the blank is opened at 1080-1120° C., then the intermediate forging is performed at 1030-1070° C., and finally the finished product is forged at 930-970° C. After the forging is completed, the ingot is ground to obtain a forged blank; (4) spraying an appropriate amount of anti-oxidation liquid on the surface of the forging blank in step (3), sending it into a heating furnace, heating it to 980-1000°C at a heating rate of 4-6°C / min, keeping it at this temperature for 1-2h, and then sending it into a rolling mill for hot rolling, with the starting rolling temperature being 900-920°C, hot rolling being performed in 6 passes, with the cumulative deformation controlled at 75%-85%, and the final rolling temperature being controlled at 860-880°C. After taking it out, cooling it in air to room temperature to obtain a hot-rolled plate; (5) The hot-rolled sheet of step (4) is fed into an annealing furnace and annealed at 770-790° C. for 1-2 h. During the annealing process, argon gas with a purity of 99.99% is continuously introduced for protection. After the annealing is completed, the sheet is taken out and cooled to room temperature in air. After grinding, pickling, straightening and shearing, a trace boron-modified Ti-Al-V-Fe alloy sheet having the following composition is obtained: Al: 3.5wt.%-4.5wt.%, V: 2.0wt.%-3.0wt.%, Fe: 1.2wt.%-1.8wt.%, O: 0.2wt.%-0.3wt.%, B: 0.04wt.%-0.08wt.%, C: ≤0.08wt.%, N: ≤0.03wt.%, H: ≤0.015wt.%, and the rest is Ti.

2. The method for preparing the high-strength and tough trace-boron-modified Ti-Al-V-Fe alloy sheet according to claim 1, characterized in that: The mass ratio of Al:V of the aluminum-vanadium master alloy in step (1) is 2:3; the purity of aluminum beans is ≥99.84%; the mass ratio of Ti:Fe of the titanium-iron master alloy is 2:1; the purity of titanium dioxide is ≥99.82%; the purity of titanium diboride particles is ≥99.57%; and the purity of titanium sponge is ≥99.9%.

3. The method for preparing the high-strength and tough trace-boron-modified Ti-Al-V-Fe alloy sheet according to claim 1, characterized in that: In the six hot rolling passes of step (4), the deformation rate of each pass is controlled to be 20-26%, 18-24%, 22-27%, 15-24%, 13-24%, and 15-22% in sequence.

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