High-quality aluminum-vanadium-carbon alloy and preparation method thereof

Abstract

The invention relates to the field of alloy materials, and discloses a high-quality aluminum-vanadium-carbon alloy and a preparation method thereof. Ammonium metavanadate, aluminum particles and carbon powder are used as raw materials, V2O5 powder is prepared through oxidizing roasting of the ammonium metavanadate, vanadium elementary substance powder is prepared through thermal reduction of the V2O5 powder, the vanadium elementary substance powder, the aluminum particles and the carbon powder are evenly mixed to obtain Al-V-C alloy powder, the Al-V-C alloy powder is put into a mold to be subjected to cold pressing to obtain an Al-V-C alloy blank, and the high-quality aluminum-vanadium-carbon alloy is obtained through vacuum sintering and suspension smelting. The alloy comprises the following components in percentage by weight: 50-75wt% of vanadium, 0.4-3.5 wt% of carbon and the balance of aluminum: less than or equal to 0.01 wt% of iron, less than or equal to 0.01 wt% of silicon, less than or equal to 0.005 wt% of oxygen and less than or equal to 0.002 wt% Ammonium metavanadate is used as a vanadium source, the cost is low, compared with an aluminum-vanadium-carbon alloy obtained through an aluminothermy method and a smelting method, the adopted method has the characteristics of high purity and high homogenization, segregation is reduced to the maximum extent, aluminum, vanadium and carbon elements are distributed more uniformly, the content of impurity elements such as oxygen and nitrogen is reduced, element burning loss is reduced, and the service life of the aluminum-vanadium-carbon alloy is prolonged. And a new thought is provided for preparation of the domestic high-quality aluminum-vanadium-carbon alloy.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and in particular to a high-quality aluminum-vanadium-carbon alloy and a preparation method thereof. Background Art

[0002] Introducing an appropriate amount of carbon into titanium alloys can form a stable carbide phase in the material. These carbides have high hardness and high melting point, which can not only significantly improve the overall strength and hardness of the alloy, but also improve its wear resistance and high-temperature creep resistance to a certain extent. In addition, carbon can also promote the formation of a dense protective layer on the surface under high temperature conditions, thereby enhancing the material's oxidation resistance and corrosion resistance. Therefore, the introduction of carbon into titanium alloys has become an important technical means to improve their comprehensive performance and extend their service life. It is especially suitable for applications such as aerospace, energy equipment, and other applications that have strict requirements on high-temperature performance. However, directly adding carbon during the smelting process of titanium alloys can easily cause element segregation and metallurgical defects in titanium alloy ingots. At present, carbon elements in titanium alloys are usually introduced in the form of intermediate alloys.

[0003] Currently, aluminum-vanadium-carbon alloy production primarily relies on aluminothermic and smelting methods. For example, Chinese patent CN101570834A uses aluminum as a reducing agent, vanadium pentoxide as an oxidizing agent, and calcium fluoride as a slagging agent. By adding carbon powder and utilizing the spontaneous exotherm generated during the metallothermic reduction reaction, the master alloy is smelted. While this preparation method is simple and energy-efficient, it can easily lead to severe elemental segregation in the alloy ingot, resulting in metallurgical defects such as carbon inclusions within the ingot and poor stability.

[0004] Therefore, how to provide a method for preparing high-quality aluminum-vanadium-carbon alloy is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a high-quality aluminum-vanadium-carbon alloy and a preparation method thereof. A high-quality aluminum-vanadium-carbon alloy can be prepared by the present invention. Through the implementation of this technology, not only can the raw material cost be saved and the alloy quality be improved, but also a new idea and method for the preparation of aluminum-vanadium-carbon alloy can be provided.

[0006] Furthermore, the present invention uses ammonium metavanadate as a vanadium source, which is low in cost. Furthermore, the aluminum-vanadium-carbon alloy ingot obtained by the present invention through single-substance vanadium preparation, material mixing, mold cold pressing, vacuum sintering, and suspension melting has good uniformity, low impurity content, and no metallurgical defects.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The first technical purpose of the present invention is to provide a method for preparing a high-quality aluminum-vanadium-carbon alloy, the method comprising the following steps:

[0009] (1) According to the grade of each element in the target alloy, a certain weight of ammonium metavanadate is weighed and placed in a fluidized bed roasting furnace, vacuumed, and oxidized and roasted in oxygen-rich air to obtain V2O5 powder;

[0010] (2) placing the V2O5 powder in a fluidized bed roasting furnace, evacuating the furnace, and reducing the powder at high temperature under a mixture of hydrogen and argon to obtain a vanadium element powder;

[0011] (3) According to the grade of each element in the target alloy, the prepared vanadium element powder is evenly mixed with aluminum particles and carbon powder to obtain a mixed powder;

[0012] (4) The mixed powder is placed in a mold and cold pressed using an electric isostatic press at room temperature to obtain an Al-VC alloy billet;

[0013] (5) tightly wrapping the Al-VC alloy billet with tantalum foil or titanium foil having a purity of more than 99%, placing the wrapped Al-VC alloy billet in a vacuum sintering furnace, evacuating the vacuum, and sintering to obtain an aluminum-vanadium-carbon alloy block;

[0014] (6) The aluminum-vanadium-carbon alloy block is placed in a suspension melting crucible, and the power of the suspension furnace is gradually increased for melting. After the melting is completed, the power is turned off, and the cooling water pump is turned on to cool down to obtain high-quality aluminum-vanadium-carbon alloy.

[0015] Preferably, the ammonium metavanadate has a purity of ≥99.0%, a particle size of 0.3-1.5 mm, and a D50 of 0.8-0.9 mm.

[0016] Preferably, during the oxidation roasting process of step (1), the filler thickness is 200-300 mm, and the vacuum degree is not higher than 1.5×10 4 Pa, the boiling layer height is 800-1400 mm, the critical wind speed is 0.5-1.1 m / s, the wind pressure is 800-1000 mmH2O, the roasting temperature is 400-750°C, the roasting time is 0.8-2.5 h, and the gas used for oxidation roasting is oxygen-enriched air with an oxygen mass fraction of 45%-55%, so that the vanadium element is fully oxidized.

[0017] Preferably, during the high temperature reduction process of step (2), the vacuum degree is 10 2 ~10 3 Pa, the boiling layer height is 700-1200 mm, the critical wind speed is 0.5-1.1 m / s, the wind pressure is 800-1000 mmH2O, the reduction temperature is 700-1100°C, the reduction time is 0.5-1 h, the mass fraction of hydrogen in the H2 / Ar mixed gas is 20-50%, and the total mass fraction of hydrogen and argon is greater than 99.99%, so that V2O5 is fully reduced.

[0018] Preferably, the purpose of vacuuming in step (1) and step (2) is to fully remove the waste gas generated during the oxidation roasting process and the water vapor generated during the thermal reduction process, and an exhaust gas collection device is provided.

[0019] Preferably, in step (3), the aluminum particles used have a purity of ≥99.99% and a particle size of 0.2-2.5 mm, the carbon powder has a purity of ≥99.0% and a particle size of 20-100 mesh, and the molar ratio of Al, V, and C is (5.3-7.6):(6.5-8.5):1.0. The mixing device is a drum mixer with a drum speed of 15-50 r / min and a mixing time of ≥12 min, preferably 12-18 min, to ensure that the materials are fully mixed and uniform, thereby reducing element segregation in the alloy ingot.

[0020] Preferably, in step (4), within 2.5 to 6 hours after the vanadium elemental powder is mixed with the aluminum particles and carbon powder, the mixed powder is loaded into a mold and vacuum-sealed with a vacuum sealer, and then cold-pressed. The cold pressing pressure is 150 MPa to 300 MPa, and the pressure holding time is 6 min to 15 min. The mixed powder is fully compacted to reduce the gaps between the powders.

[0021] Preferably, in step (5), the vacuum degree of the vacuum sintering system is 0.05Pa to 0.001Pa, the sintering temperature is 800°C to 1200°C, and the sintering time is 60 to 240 minutes, so that the alloy blank is fully sintered and the powder particles are fully diffused.

[0022] Preferably, during the vacuum suspension melting process of step (6), the first vacuum melting, the second vacuum melting, the third vacuum melting, the fourth vacuum melting and the fifth vacuum melting are carried out in sequence; wherein,

[0023] The vacuum degree of the first vacuum melting is less than 15 Pa, the melting power is 80-120 kW, and the melting time is 10-20 minutes;

[0024] The second vacuum melting process has a vacuum degree of less than 15 Pa, a melting power of 120-135 kW, and a melting time of 3-5 minutes;

[0025] The third vacuum melting process has a vacuum degree of less than 15 Pa, a melting power of 140-160 kW, and a melting time of 4-7 minutes;

[0026] The fourth vacuum melting process has a vacuum degree of less than 50 Pa, a melting power of 170-185 kW, and a melting time of 3-5 minutes;

[0027] The fifth vacuum melting process has a vacuum degree of less than 50 Pa, a melting power of 195 to 210 kW, and a melting time of 10 to 20 minutes.

[0028] Preferably, the suspension smelting equipment in step (6) is a split-type water-cooled copper crucible, and the cooling water circulation volume is 10 to 15 m 3 / h, cooling water pressure is 3~3.5MPa, water inlet temperature is 20~25℃, and water outlet temperature is 45~50℃.

[0029] The aluminum-vanadium-carbon alloy produced by the method of the present invention has the following contents: vanadium 50-75wt%, carbon 0.4-3.5wt%, aluminum balance, iron ≤0.01wt%, silicon ≤0.01wt%, oxygen ≤0.005wt%, nitrogen ≤0.002wt%.

[0030] It can be seen from the above technical solutions that, compared with the prior art, the present invention provides a high-quality aluminum-vanadium-carbon alloy and a preparation method thereof, which has the following excellent effects:

[0031] 1) The present invention uses ammonium metavanadate, aluminum particles and carbon powder as raw materials, and obtains V2O5 powder by oxidative roasting of ammonium metavanadate, thermally reducing the V2O5 powder to prepare vanadium element powder, and uniformly mixing the vanadium element powder with aluminum particles and carbon powder to obtain Al-VC alloy powder. The Al-VC alloy billet is then cold-pressed into a mold, and high-quality aluminum-vanadium-carbon alloy is obtained through vacuum sintering and suspension melting.

[0032] 2) The present invention uses ammonium metavanadate as a raw material, which is low in cost. The aluminum-vanadium-carbon alloy ingot obtained by preparing vanadium alone, mixing materials, cold pressing into a mold, vacuum sintering, and suspension melting has good uniformity, low impurity content, small element burnout, and no metallurgical defects, providing a new idea and method for the preparation of aluminum-vanadium-carbon alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0034] Figure 1 This is a sampling point diagram of aluminum-vanadium-carbon alloy ingots.

[0035] Figure 2 This is the metallographic diagram of the aluminum-vanadium-carbon alloy of Example 1.

[0036] Figure 3 This is the metallographic diagram of the aluminum-vanadium-carbon alloy of Example 2.

[0037] Figure 4 This is the metallographic diagram of the aluminum-vanadium-carbon alloy of Example 3.

[0038] Figure 5 This is the metallographic diagram of the aluminum-vanadium-carbon alloy of Example 4.

[0039] Figure 6 This is the metallographic diagram of the aluminum-vanadium-carbon alloy of comparative example 1. DETAILED DESCRIPTION

[0040] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] The term "embodiment" is used herein specifically to describe any embodiment as "exemplary," and should not be construed as superior or preferable to other embodiments. Performance indicators in the embodiments of this application were tested using conventional testing methods in the art, unless otherwise specified. It should be understood that the terms used in this application are intended solely to describe specific implementations and are not intended to limit the disclosure herein.

[0042] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0043] In order to better illustrate the content of this application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that this application can be implemented without certain specific details. In the examples, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of this application.

[0044] Under the premise of no conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of this application.

[0045] The invention discloses a high-quality aluminum-vanadium-carbon alloy and a preparation method thereof.

[0046] For a better understanding of the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as limiting the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above invention content are also considered to fall within the scope of protection of the present invention.

[0047] Example 1

[0048] A method for preparing a high-quality aluminum-vanadium-carbon alloy comprises the following steps:

[0049] Weigh 57.41 kg of ammonium metavanadate and place it in a fluidized bed roasting furnace with a filler thickness of 230 mm. Close the furnace and start the Roots pump to evacuate to 1.2 × 10 3 The boiling layer height was controlled at 950 mm, the critical wind speed was 0.8 m / s, the blast pressure was 800 mmH2O, the baking temperature was 600°C, the baking time was 1.2 h, and the oxygen content of the oxygen-enriched air was 50%.

[0050] The prepared V2O5 powder was placed in a fluidized bed roasting furnace. After cooling, the oxygen-enriched air was turned off, the vacuum was evacuated to 100 Pa, and electric heating was applied. The boiling layer height was controlled to 800 mm, the critical wind speed was 0.8 m / s, the wind pressure was 800 mmH2O, the reduction temperature was 950°C, the reduction time was 1 hour, the mass fraction of hydrogen in the H2 / Ar mixture was 35%, and the total mass fraction of hydrogen and argon was greater than 99.99%, so that the V2O5 was fully reduced.

[0051] The prepared vanadium elemental powder, 12.50 kg of aluminum particles, and 0.80 kg of carbon powder were placed in a drum mixer with a drum speed of 50 r / min and a mixing time of 13 min to mix the materials evenly to obtain a mixed powder.

[0052] The mixed powder was placed in a mold, vacuum sealed with a vacuum sealer, and then cold pressed with a cold pressing pressure of 200 MPa and a holding time of 12 minutes.

[0053] The cold-pressed Al-VC alloy billet was tightly wrapped with titanium foil with a purity of more than 99%, placed in a vacuum sintering furnace, evacuated to 0.01 Pa, and sintered with power at a sintering temperature of 1100°C and a sintering time of 120 min.

[0054] The aluminum-vanadium-carbon alloy block obtained by vacuum sintering is placed in a suspension melting crucible, and the melting power is gradually increased to perform vacuum suspension melting. During the vacuum suspension melting process, the first vacuum melting, the second vacuum melting, the third vacuum melting, the fourth vacuum melting and the fifth vacuum melting are performed in sequence; wherein,

[0055] The vacuum degree of the first vacuum melting is 7 Pa, the melting power is 100 kW, and the melting time is 20 min;

[0056] The second vacuum melting process has a vacuum degree of 8 Pa, a melting power of 130 kW, and a melting time of 5 minutes;

[0057] The third vacuum melting process has a vacuum degree of 10 Pa, a melting power of 150 kW, and a melting time of 6 minutes;

[0058] The fourth vacuum melting process has a vacuum degree of 16 Pa, a melting power of 180 kW, and a melting time of 5 min;

[0059] The fifth vacuum melting process has a vacuum degree of 21 Pa, a melting power of 200 kW, and a melting time of 10 min.

[0060] After the smelting was completed, the power was turned off and the cooling water pump was turned on to cool for 2.5 hours to obtain 37.62 kg of aluminum-vanadium-carbon alloy. The multi-point sampling data are shown in Table 1.

[0061] Table 1 Analysis of sampling results of aluminum vanadium carbon alloy prepared in Example 1

[0062]

[0063] Example 2

[0064] A method for preparing a high-quality aluminum-vanadium-carbon alloy comprises the following steps:

[0065] Only 53.27 kg of ammonium metavanadate in Example 1 was weighed, and elemental vanadium was obtained after oxidative roasting and thermal reduction. The obtained elemental vanadium was mixed with 11.60 kg of aluminum particles and 0.74 kg of carbon powder. After cold pressing into a mold, vacuum sintering, and suspension melting, 34.37 kg of aluminum-vanadium-carbon alloy ingots were obtained. The multi-point sampling data are shown in Table 2.

[0066] Table 2 Analysis of sampling results of aluminum vanadium carbon alloy prepared in Example 2

[0067]

[0068] Example 3

[0069] A method for preparing a high-quality aluminum-vanadium-carbon alloy comprises the following steps:

[0070] Only the mixing time in Example 1 was changed to 15 min, and 37.60 kg of aluminum-vanadium-carbon alloy ingots were obtained. The multi-point sampling data are shown in Table 3.

[0071] Table 3 Analysis of sampling results of aluminum vanadium carbon alloy prepared in Example 3

[0072]

[0073]

[0074] Example 4

[0075] Only the holding time of the cold pressing in the mold in Example 1 was changed to 14 minutes, and 37.63 kg of aluminum-vanadium-carbon alloy ingots were obtained. The multi-point sampling data are shown in Table 4.

[0076] Table 4 Analysis of sampling results of aluminum vanadium carbon alloy prepared in Example 4

[0077]

[0078] In order to further demonstrate the beneficial effects of the present invention and to better understand the present invention, the following comparative examples are provided to further illustrate the technical features disclosed in the present invention, but they should not be construed as limiting the present invention. Other improvements made by those skilled in the art based on the above invention without inventive work are also considered to fall within the scope of protection of the present invention.

[0079] Comparative Example 1

[0080] Only the alloy powder mixed in the mixer in Example 1 was directly subjected to suspension melting to obtain 37.16 kg of aluminum-vanadium-carbon alloy ingots. The alloy multi-point sampling data are shown in Table 5.

[0081] Table 5 Analysis of sampling results of aluminum tungsten titanium alloy prepared in comparative example 1

[0082]

[0083] The elemental analysis and metallographic structures of the above examples and comparative examples show that alloy ingots that were not cold-pressed and vacuum-sintered exhibited high elemental burnout, significant elemental segregation, and numerous fine pores within the alloy. The aluminum-vanadium-carbon alloy prepared using the method of the present invention exhibits uniform elemental distribution, low impurity content, minimal elemental burnout, and a pure metallographic structure, significantly improving the quality of the aluminum-vanadium-carbon alloy.

[0084] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing high-quality aluminum-vanadium-carbon alloy, characterized in that: The method comprises the following steps: (1) According to the grade of each element in the target alloy, a certain weight of ammonium metavanadate is weighed and placed in a fluidized bed roasting furnace, vacuumed, and oxidatively roasted to obtain V2O5 powder; (2) placing the V2O5 powder in a fluidized bed roasting furnace, evacuating the furnace, and reducing the powder at high temperature under a mixture of hydrogen and argon to obtain a vanadium element powder; (3) According to the grade of each element in the target alloy, the prepared vanadium element powder is evenly mixed with aluminum particles and carbon powder to obtain a mixed powder; (4) placing the mixed powder into a mold and cold pressing it using an electric isostatic press at room temperature to obtain an Al-VC alloy billet; (5) tightly wrapping the Al-VC alloy billet with tantalum foil or titanium foil having a purity of 99% or more, placing the wrapped Al-VC alloy billet in a vacuum sintering furnace, evacuating the vacuum, and sintering to obtain an aluminum-vanadium-carbon alloy block; (6) The aluminum-vanadium-carbon alloy block is subjected to vacuum suspension melting, and after melting, the block is cooled to obtain a high-quality aluminum-vanadium-carbon alloy.

2. The preparation method according to claim 1, characterized in that During the oxidation roasting process of step (1), the filler thickness is 200-300 mm, and the vacuum degree is not higher than 1.5×10 4 Pa, the boiling layer height is 800-1400 mm, the critical wind speed is 0.5-1.1 m / s, the wind pressure is 800-1000 mmH2O, the roasting temperature is 400-750°C, the roasting time is 0.8-2.5 h, and the gas used for oxidation roasting is oxygen-enriched air with an oxygen mass fraction of 45%-55%, so that the vanadium element is fully oxidized.

3. The preparation method according to claim 1, characterized in that During the high temperature reduction process of step (2), the vacuum degree is 10 2 ~10 3 Pa, the boiling layer height is 700-1200 mm, the critical wind speed is 0.5-1.1 m / s, the wind pressure is 800-1000 mmH2O, the reduction temperature is 700-1100°C, the reduction time is 0.5-1 h, the mass fraction of hydrogen in the H2 / Ar mixed gas is 20-50%, and the total mass fraction of hydrogen and argon is greater than 99.99%, so that V2O5 is fully reduced.

4. The preparation method according to claim 1, characterized in that In step (3), the purity of the aluminum particles is ≥99.99%, and the particle size is 0.2-2.5 mm; the purity of the carbon powder is ≥99.0%, and the particle size is 20-100 mesh; the molar ratio of Al, V, and C elements is (5.3-7.6):(6.5-8.5):1.0; the mixing device is a drum mixer, the mixer drum speed is 15-50 r / min, and the mixing time is 12-18 min.

5. The preparation method according to claim 1, characterized in that In step (4), within 2.5 to 6 hours after the vanadium elemental powder is mixed with the aluminum particles and carbon powder, the mixed powder is placed in a mold and vacuum-sealed with a vacuum sealer, and then cold-pressed. The cold-pressing pressure is 150 to 300 MPa, and the pressure holding time is 6 to 15 minutes.

6. The preparation method according to claim 1, characterized in that In the step (5), the vacuum degree of the vacuum sintering system is 0.05 Pa to 0.001 Pa, the sintering temperature is 800° C. to 1200° C., and the sintering time is 60 to 240 minutes.

7. The preparation method according to claim 1, characterized in that During the vacuum suspension melting process of step (6), the first vacuum melting, the second vacuum melting, the third vacuum melting, the fourth vacuum melting and the fifth vacuum melting are carried out in sequence; wherein, The vacuum degree of the first vacuum melting is less than 15 Pa, the melting power is 80-120 kW, and the melting time is 10-20 minutes; The second vacuum melting process has a vacuum degree of less than 15 Pa, a melting power of 120-135 kW, and a melting time of 3-5 minutes; The third vacuum melting process has a vacuum degree of less than 15 Pa, a melting power of 140-160 kW, and a melting time of 4-7 minutes; The fourth vacuum melting process has a vacuum degree of less than 50 Pa, a melting power of 170-185 kW, and a melting time of 3-5 minutes; The fifth vacuum melting process has a vacuum degree of less than 50 Pa, a melting power of 195 to 210 kW, and a melting time of 10 to 20 minutes.

8. The preparation method according to claim 1, characterized in that The suspension smelting equipment in step (6) is a split-type water-cooled copper crucible with a cooling water circulation volume of 10 to 15 m 3 / h, cooling water pressure is 3~3.5MPa, water inlet temperature is 20~25℃, and water outlet temperature is 45~50℃.

9. A high-quality aluminum-vanadium-carbon alloy prepared by the method of claim 1, characterized in that: The alloy contents are as follows: Vanadium 50-75wt%, carbon 0.4-3.5wt%, aluminum balance, iron ≤0.01wt%, silicon ≤0.01wt%, oxygen ≤0.005wt%, nitrogen ≤0.002wt%.

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