Method for producing low-oxygen vanadium-aluminum alloy

Abstract

A method for producing a low-oxygen vanadium-aluminum alloy comprises the following steps that (1) a vanadium-aluminum alloy block and a metal aluminum block are added into a vacuum melting furnace, the temperature of the vacuum melting furnace is increased to 1600-1650 DEG C in the furnace, the temperature is kept constant, and vacuum melting is conducted for 1-2 h; and (2) neodymium is added into the alloy treated in the step (1), the temperature of a vacuum melting furnace is increased to the temperature in the furnace to be 1700-1780 DEG C, the temperature is kept constant, power-on vacuum melting is conducted for 1-2 h, then the temperature in the furnace is reduced to the room temperature, and the vanadium-aluminum alloy with the oxygen content smaller than 0.01% is obtained. According to the method, secondary vacuum melting is carried out on the basis of a conventional vanadium-aluminum alloy, the oxygen content in the obtained vanadium-aluminum alloy is lower than 0.01%, and the requirement of military titanium materials is met.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for producing low-oxygen vanadium aluminum alloy. Background Art

[0002] Vanadium aluminum alloy is an element additive for producing titanium alloy and special alloys containing iron and vanadium. Vanadium is a strong stabilizer in titanium alloy. Vanadium aluminum alloy can improve the heat resistance and cold processing properties of the alloy, so that the alloy has good welding properties and relatively high mechanical strength. The current production methods of vanadium aluminum alloy are based on the aluminum thermal reduction method. The raw materials used are vanadium pentoxide, aluminum, lime and fluorite. After drying, batching and mixing, the raw materials are placed in a reactor, magnesium chips are added to the surface and ignited to start the smelting process of self-exothermic reaction. After the reaction is completed, it is cooled for a period of time, the alloy oxide scale is removed, and vanadium aluminum alloy is obtained. As a special alloy material, vanadium aluminum alloy is the most important additive for the production of titanium alloy, especially the intermediate alloy that must be added for the preparation of titanium alloy materials for aviation and military industry. Since oxygen in titanium alloy has an extremely adverse effect on the physical properties of the alloy, aviation and military users have increasingly stringent requirements on the oxygen content of raw material vanadium aluminum alloy. Low oxygen content vanadium aluminum alloy is the primary requirement of aviation and military titanium alloy enterprises. The oxygen content of ordinary conventional vanadium aluminum alloys is generally high, about 0.2%, which cannot meet the requirements of military titanium materials.

[0003] At present, the low-oxygen vanadium aluminum alloy produced in China is mainly AlV55. Most manufacturers adopt a two-step method, using vanadium flakes, aluminum particles, and slag adjusting agents, mixed in a certain ratio, smelting AlV85, and then mixing AlV85 with an appropriate proportion of aluminum particles, vacuum melting to remove impurities and change the vanadium grade, and produce low-oxygen AlV55 or other grades of vanadium aluminum alloy products, generally with an oxygen content of 0.04-0.06% in the vanadium aluminum alloy. At present, it seems that the production of low-oxygen vanadium aluminum alloys with an oxygen content below 0.06% usually requires a two-step method: the first step is to use high-quality vanadium oxide and aluminum powder to mix and smelt to obtain a primary vanadium aluminum alloy; the second step is to crush the primary vanadium aluminum alloy and add high-quality aluminum powder to adjust the composition to the required range, and then melt it in a vacuum induction furnace, and refine and degas under vacuum conditions to reduce the oxygen content in the vanadium aluminum alloy to below 0.06%. The above production method has the defects of long process flow, high energy consumption, and high cost. The oxygen content in the resulting vanadium aluminum alloy is still not low enough. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, provide a method for producing low-oxygen vanadium aluminum alloy, and reduce the oxygen content in the obtained vanadium aluminum alloy.

[0005] The technical solution adopted by the present invention to solve the technical problem is a method for producing a low-oxygen vanadium aluminum alloy, comprising the following steps: (1) Add vanadium aluminum alloy blocks and metal aluminum blocks into a vacuum melting furnace, increase the temperature of the vacuum melting furnace to 1600-1650°C, keep the temperature constant, and vacuum melt for 1-2 hours; (2) Add neodymium to the alloy treated in step (1), raise the temperature of the vacuum melting furnace to 1700-1780°C, keep the temperature constant, turn on the power for vacuum melting for 1-2 hours, and then lower the temperature of the furnace to room temperature to obtain a vanadium aluminum alloy with an oxygen content of less than 0.01%.

[0006] Furthermore, in step (1), the oxygen content in the vanadium aluminum alloy block is less than 0.5wt%. If the oxygen content in the vanadium aluminum alloy block is greater than 0.5wt%, the oxygen content can be reduced to less than 0.5% by other methods, and then the method of the present invention can be used to further reduce the oxygen content.

[0007] Furthermore, in step (1), the mass of the metal aluminum block is equivalent to 0.5-2.0% of the mass of the vanadium aluminum alloy block.

[0008] Furthermore, in step (1), the temperature of the vacuum melting furnace is increased to 1600-1650°C at a rate of 50-100°C / min. In step (1), an aluminum block is first added for the first smelting to remove a portion of the oxygen in the vanadium aluminum alloy to facilitate subsequent deep deoxidation. Studies have shown that increasing the temperature in a programmed heating manner is more conducive to deoxidation. A heating rate that is too fast is not conducive to the removal of oxygen, but a heating rate that is too slow affects production efficiency.

[0009] Furthermore, in step (1) and step (2), the vacuum degree in the vacuum melting furnace is 5 to 50 Pa.

[0010] Furthermore, in step (2), the mass of neodymium is equivalent to 0.001-0.005% of the mass of the raw material vanadium aluminum alloy. Studies have shown that adding a trace amount of neodymium for a second smelting can further remove oxygen from the vanadium aluminum alloy and further reduce the oxygen content in the vanadium aluminum alloy. If there is unreacted neodymium, it will play a role of microalloying in the vanadium aluminum alloy, which will not affect the comprehensive properties of the material and may also improve the bonding properties of the material.

[0011] Furthermore, in step (2), the temperature of the vacuum melting furnace is increased at a rate of 20-30°C / min to a furnace temperature of 1700-1780°C. Studies have shown that slightly increasing the furnace temperature after the first melting combined with programmed heating can achieve better oxygen removal effects. Too fast a heating rate is not conducive to oxygen removal, and too slow a heating rate affects production efficiency.

[0012] Furthermore, in step (2), the voltage of the power supply is 20-50 V. Studies have shown that applying a lower voltage can accelerate the removal of oxygen, and the oxygen removal is more thorough, thereby obtaining a vanadium-aluminum alloy with a lower oxygen content.

[0013] Furthermore, in step (2), the temperature in the furnace is lowered to room temperature at a rate of 50-100°C / min.

[0014] The present invention first adds an aluminum block for the first smelting to remove a portion of the oxygen in the vanadium aluminum alloy, so as to facilitate the subsequent deep deoxygenation. Increasing the temperature in a programmed temperature rise manner is more conducive to deoxygenation. A too fast heating rate is not conducive to the removal of oxygen, but a too slow heating rate affects the production efficiency. The present invention adds a trace amount of neodymium for the second smelting, which can further remove the oxygen in the vanadium aluminum alloy and further reduce the oxygen content in the vanadium aluminum alloy. If there is unreacted neodymium, it plays a role of microalloying in the vanadium aluminum alloy, will not affect the comprehensive properties of the material, and may also improve the bonding properties of the material. After the first smelting, the temperature in the furnace is slightly increased, and the oxygen removal effect can be better combined with the programmed temperature rise. Applying a lower voltage can accelerate the removal of oxygen, and the oxygen removal is more thorough. A vanadium aluminum alloy with a lower oxygen content can be obtained.

[0015] The present invention performs secondary vacuum smelting on the basis of conventional vanadium-aluminum alloy, and the oxygen content of the obtained vanadium-aluminum alloy is lower than 0.01%, which meets the demand for titanium materials in military industry. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with specific embodiments. Example 1

[0017] The method for producing low-oxygen vanadium aluminum alloy of this embodiment comprises the following steps: (1) Add vanadium-aluminum alloy blocks and metal aluminum blocks into a vacuum melting furnace, raise the temperature of the vacuum melting furnace to 1600°C, keep the temperature constant, and perform vacuum melting for 2 hours; In step (1), the oxygen content in the vanadium aluminum alloy block is 0.2 wt %.

[0018] In step (1), the mass of the metal aluminum block is equivalent to 0.5% of the mass of the vanadium aluminum alloy block.

[0019] In step (1), the temperature of the vacuum melting furnace is increased at a rate of 100°C / min to a furnace temperature of 1600°C.

[0020] In step (1) and step (2), the vacuum degree in the vacuum melting furnace is 30 Pa.

[0021] (2) Neodymium is added to the alloy treated in step (1), the temperature of the vacuum melting furnace is increased to 1700°C, the temperature is kept constant, the vacuum melting is performed for 2 hours, and then the temperature in the furnace is lowered to room temperature to obtain a vanadium aluminum alloy with an oxygen content of 0.005%.

[0022] In step (2), the mass of neodymium is equivalent to 0.003% of the mass of the raw material vanadium aluminum alloy.

[0023] In step (2), the temperature of the vacuum melting furnace is increased at a rate of 20°C / min to a furnace temperature of 1700°C.

[0024] In step (2), the power supply voltage is 20V.

[0025] In step (2), the temperature in the furnace is lowered to room temperature at a rate of 50°C / min.

[0026] In this embodiment, secondary vacuum melting is performed on the basis of conventional vanadium-aluminum alloy, and the oxygen content of the obtained vanadium-aluminum alloy is less than 0.01%, which meets the demand for titanium materials in the military industry. Example 2

[0027] The method for producing low-oxygen vanadium aluminum alloy of this embodiment comprises the following steps: (1) Add vanadium-aluminum alloy blocks and metal aluminum blocks into a vacuum melting furnace, raise the temperature of the vacuum melting furnace to 1650°C, keep the temperature constant, and perform vacuum melting for 1.5 hours; In step (1), the oxygen content in the vanadium aluminum alloy block is less than 0.3 wt %.

[0028] In step (1), the mass of the metal aluminum block is equivalent to 0.8% of the mass of the vanadium aluminum alloy block.

[0029] In step (1), the temperature of the vacuum melting furnace is increased at a rate of 100°C / min to a furnace temperature of 1650°C.

[0030] In step (1) and step (2), the vacuum degree in the vacuum melting furnace is 5 Pa.

[0031] (2) Neodymium is added to the alloy treated in step (1), the temperature of the vacuum melting furnace is increased to 1780°C, the temperature is kept constant, vacuum melting is performed for 1 hour, and then the temperature in the furnace is lowered to room temperature to obtain a vanadium aluminum alloy with an oxygen content of 0.008%.

[0032] In step (2), the mass of neodymium is equivalent to 0.005% of the mass of the raw material vanadium aluminum alloy.

[0033] In step (2), the temperature of the vacuum melting furnace is increased at a rate of 30°C / min to a furnace temperature of 1780°C.

[0034] In step (2), the power supply voltage is 20V.

[0035] In step (2), the temperature in the furnace is lowered to room temperature at a rate of 100°C / min.

[0036] In this embodiment, secondary vacuum melting is performed on the basis of conventional vanadium-aluminum alloy, and the oxygen content of the obtained vanadium-aluminum alloy is less than 0.01%, which meets the demand for titanium materials in the military industry. Example 3

[0037] The method for producing low-oxygen vanadium aluminum alloy of this embodiment comprises the following steps: (1) Add vanadium-aluminum alloy blocks and metal aluminum blocks into a vacuum melting furnace, raise the temperature of the vacuum melting furnace to 1650°C, keep the temperature constant, and perform vacuum melting for 1 hour; In step (1), the oxygen content in the vanadium aluminum alloy block is 0.2 wt %.

[0038] In step (1), the mass of the metal aluminum block is equivalent to 2.0% of the mass of the vanadium aluminum alloy block.

[0039] In step (1), the temperature of the vacuum melting furnace is increased at a rate of 80°C / min to a furnace temperature of 1650°C.

[0040] In step (1) and step (2), the vacuum degree in the vacuum melting furnace is 40 Pa.

[0041] (2) Neodymium is added to the alloy treated in step (1), the temperature of the vacuum melting furnace is increased to 1780°C, the temperature is kept constant, vacuum melting is performed for 1-2 hours, and then the temperature in the furnace is lowered to room temperature to obtain a vanadium aluminum alloy with an oxygen content of 0.006%.

[0042] In step (2), the mass of neodymium is equivalent to 0.003% of the mass of the raw material vanadium aluminum alloy.

[0043] In step (2), the temperature of the vacuum melting furnace is increased at a rate of 30°C / min to a furnace temperature of 1780°C.

[0044] In step (2), the power supply voltage is 50V.

[0045] In step (2), the temperature in the furnace is lowered to room temperature at a rate of 100°C / min.

[0046] In this embodiment, secondary vacuum melting is performed on the basis of conventional vanadium-aluminum alloy, and the oxygen content of the obtained vanadium-aluminum alloy is less than 0.01%, which meets the demand for titanium materials in the military industry.

[0047] Comparative Example 1 In this comparative example, except that neodymium is not added in step (2), other parameters are the same as those in Example 1. The oxygen content of the vanadium aluminum alloy obtained in this comparative example is 0.10%.

[0048] Comparative Example 2 In this comparative example, except that the temperature of the vacuum melting furnace is not raised to 1700° C. in step (2), and the temperature of the vacuum melting furnace is kept at 1600° C. in step (2), other parameters are the same as those in Example 1. The oxygen content of the vanadium aluminum alloy obtained in this comparative example is 0.06%.

[0049] Comparative Example 3 In this comparative example, except that the step (2) is not "powered on", other parameters are the same as those in Example 1. The oxygen content of the vanadium aluminum alloy obtained in this comparative example is 0.08%.

[0050] Comparative Example 4 In this comparative example, except that in step (2), "the temperature of the vacuum melting furnace is increased to 1700° C. in 30 seconds" is adopted instead of "the temperature of the vacuum melting furnace is increased to 1700° C. in 20° C. / min", other parameters are the same as those in Example 1. The oxygen content of the vanadium aluminum alloy obtained in this comparative example is 0.06%.

Claims

1. A method for producing a low-oxygen vanadium aluminum alloy, characterized in that: The following steps are involved: (1) Add vanadium aluminum alloy blocks and metal aluminum blocks into a vacuum melting furnace, increase the temperature of the vacuum melting furnace to 1600-1650°C, keep the temperature constant, and vacuum melt for 1-2 hours; (2) Add neodymium to the alloy treated in step (1), raise the temperature of the vacuum melting furnace to 1700-1780°C, keep the temperature constant, turn on the power for vacuum melting for 1-2 hours, and then lower the temperature of the furnace to room temperature to obtain a vanadium aluminum alloy with an oxygen content of less than 0.01%.

2. The method for producing low-oxygen vanadium aluminum alloy according to claim 1, characterized in that: In step (1), the oxygen content in the vanadium aluminum alloy block is less than 0.5 wt %.

3. The method for producing a low-oxygen vanadium aluminum alloy according to claim 1 or 2, characterized in that: In step (1), the mass of the metal aluminum block is equivalent to 0.5-2.0% of the mass of the vanadium aluminum alloy block.

4. The method for producing a low-oxygen vanadium aluminum alloy according to claim 1 or 2, characterized in that: In step (1), the temperature of the vacuum melting furnace is increased at a rate of 50-100°C / min to a furnace temperature of 1600-1650°C.

5. The method for producing low-oxygen vanadium aluminum alloy according to claim 1 or 2, characterized in that: In step (1) and step (2), the vacuum degree in the vacuum melting furnace is 5 to 50 Pa.

6. The method for producing low-oxygen vanadium aluminum alloy according to claim 1 or 2, characterized in that: In step (2), the mass of neodymium is equivalent to 0.001-0.005% of the mass of the raw material vanadium aluminum alloy.

7. The method for producing low-oxygen vanadium aluminum alloy according to claim 1 or 2, characterized in that: In step (2), the temperature of the vacuum melting furnace is increased at a rate of 20-30°C / min to a furnace temperature of 1700-1780°C.

8. The method for producing low-oxygen vanadium aluminum alloy according to claim 1 or 2, characterized in that: In step (2), the power supply voltage is 20-50V.

9. The method for producing low-oxygen vanadium aluminum alloy according to claim 1 or 2, characterized in that: In step (2), the temperature in the furnace is lowered to room temperature at a rate of 50-100°C / min.