阅读说明：本技术 航空航天级高钒铝合金降低氧、氮的熔炼工艺及真空装置 (Smelting process and vacuum device for reducing oxygen and nitrogen of aerospace-level high-vanadium aluminum alloy ) 是由 张金波 李嘉诚 郑杰 于 2020-06-22 设计创作，主要内容包括：本发明提供了一种航空航天级高钒铝合金降低氧、氮的熔炼工艺及真空装置,其包括以下的步骤：配料、混料与装炉反应、冷却、拆炉与称重、喷砂与精整、破碎、挑料、成品检验入库。本发明在装炉反应结束时,将真空装置加装在坩埚上部,并启动该装置,将坩埚内的气体抽出,可以有效地减少钒铝合金熔炼过程中因空气存在而带入的氧、氮等杂质元素的含量。通过控制杂质元素的含量来大幅提高钒铝合金的纯度,提升合金的品质,满足航空航天级中间合金的使用要求。(The invention provides a smelting process and a vacuum device for reducing oxygen and nitrogen of an aerospace high-vanadium aluminum alloy, which comprises the following steps: batching, mixing and furnace charging reaction, cooling, furnace dismounting and weighing, sand blasting and finishing, crushing, material picking, finished product inspection and warehousing. When the charging reaction is finished, the vacuum device is arranged on the upper part of the crucible, and the device is started to extract the gas in the crucible, so that the content of oxygen, nitrogen and other impurity elements brought in by the existence of air in the vanadium-aluminum alloy smelting process can be effectively reduced. The purity of the vanadium-aluminum alloy is greatly improved by controlling the content of impurity elements, the quality of the alloy is improved, and the use requirement of aerospace-grade intermediate alloy is met.)

1. The smelting process for reducing the oxygen and nitrogen contents of the aerospace-level high-vanadium aluminum alloy is characterized by comprising the following steps of:

step 1), preparing materials: selecting pure vanadium pentoxide, pure aluminum powder, pure fluorite powder and potassium chlorate with proper granularity according to the set mass percentage ratio of the materials to form materials before mixing, and drying;

step 2), mixing and charging reaction: putting 100kg of dried vanadium pentoxide, 59.6kg of aluminum powder, 15kg of fluorite powder and 0.5kg of potassium chlorate into a mixer, mixing for 30-60 minutes at 120-130 ℃ to form a uniformly mixed material, then putting the uniformly mixed material into a crucible (5) to form a furnace charge (6), and dotting a small amount of magnesium chipsAfter burning, putting the mixture into a crucible to ignite furnace charge to perform aluminothermic reaction of 3V₂O₅+10A_l＝6V+5Al₂O₃；

Step 3), cooling: excessive aluminum and a reactant vanadium form a vanadium-aluminum alloy, a vacuum device is covered on the upper part of a crucible (5) for airtight connection in the final stage of smelting, a control valve (3) is opened for vacuumizing while a vacuum mechanical pump (1) and a vacuum Roots pump (2) are started to form negative pressure in the crucible (5), and the control valve (3) is closed after the proper vacuum degree is reached, so that a reacted material (6) is naturally cooled in the crucible (5);

step 4), dismantling the furnace and weighing: after the materials (6) after the crucible reaction are completely reacted and crystallized, cooling for 2-4 hours, then disassembling the furnace, weighing and recording the discharged vanadium-aluminum alloy blocks;

step 5), sand blasting and finishing: carrying out sand blasting treatment on the cooled vanadium-aluminum alloy block, cleaning slag and furnace ash attached to the surface, polishing the surface of the vanadium-aluminum alloy block by using a grinding machine to grind an oxide layer and surface defects, and blowing the surface by using high-pressure air until the natural color of the metal is exposed, and placing the vanadium-aluminum alloy block far away from the grinding machine;

step 6), crushing: crushing the polished vanadium-aluminum alloy blocks into large blocks, adding the large blocks into a crusher for further crushing and refining, and sieving the large blocks by using a sieve with the specification of 6mm, wherein the vanadium-aluminum alloy blocks larger than 6mm need to be crushed again; immediately barreling, weighing and marking batch numbers for the vanadium-aluminum alloy blocks sieved in the same batch;

step 7), selecting materials: manually picking out impurities, foreign matters or oxides from the vanadium-aluminum alloy blocks under the crushed screens;

step 8), finished product inspection and warehousing: and (4) performing selective inspection on the picked vanadium-aluminum alloy blocks by inspectors according to 5 percent of the vanadium-aluminum alloy blocks in the batch, judging the vanadium-aluminum alloy blocks to be qualified and warehousing the vanadium-aluminum alloy blocks without impurities, foreign matters and oxides.

2. The aerospace grade high vanadium aluminum alloy oxygen and nitrogen content reduction melting process as claimed in claim 1, wherein in step 3), the suitable vacuum degree is 3Pa or less.

3. The smelting process for reducing the oxygen and nitrogen contents of the aerospace grade high vanadium-aluminum alloy according to claim 1 or 2, wherein in the step 4), if the vanadium-aluminum alloy is smelted in hot and humid weather, the cooling is prolonged to be more than 4-5 hours, and the furnace is dismantled.

4. The aerospace grade high vanadium aluminum alloy oxygen and nitrogen content reduction melting process vacuum device according to claim 1, wherein the vacuum mechanical pump (1), the vacuum roots pump (2), the control valve (3) and the crucible cover plate (4) are connected in sequence through pipelines; wherein the crucible cover plate (4) is connected with the crucible (5) in an airtight manner; when the vacuum mechanical pump (1) and the vacuum roots pump (2) are started for vacuumizing, the control valve (3) is opened, gas existing in the crucible (5) is pumped out, the control valve (3) is closed after the proper vacuum degree is achieved, and the materials (6) after reaction in the crucible are isolated from the outside air; the crucible cover plate (4) is a flange with threads and is screwed and hermetically connected with the threads processed on the outer edge of the upper opening of the crucible (5); the crucible (5) is a copper crucible.

Technical Field

The invention belongs to the technical field of metal materials, relates to an intermediate alloy material for titanium alloy, and particularly relates to a smelting process for reducing oxygen and nitrogen of aerospace high-vanadium aluminum alloy and a vacuum device.

Background

The application of titanium alloy materials in the fields of aerospace, petrochemical industry, shipbuilding and the like is increasingly expanded, and the preparation capacity and the industrialization level of the titanium alloy materials in a country become important factors for measuring the comprehensive national strength of the country.

In the process of preparing the titanium alloy, different grades of titanium alloy are generated due to different performance requirements, the different grades of the titanium alloy depend on different addition elements in the components of the titanium alloy, and the alloy serving as the addition element is called as an intermediate alloy. The vanadium-aluminum alloy is a common intermediate alloy and is mainly used as an intermediate alloy for manufacturing titanium alloy and high-temperature titanium alloy and an element additive of titanium alloy with certain special purposes.

In addition, the vanadium-aluminum alloy is a high-grade alloy material used in the field of aerospace and navigation, has the characteristics of high hardness, elasticity, seawater corrosion resistance, light weight and the like, and can be used for manufacturing seaplanes and water gliders besides aerospace. Only a few countries such as the United states and Germany can be industrially produced in the world. At present, the vanadium-aluminum intermediate alloy in China has small consumption, and mainly meets the requirements of special fields such as aerospace, military and the like. With the development needs of Chinese titanium materials and related special fields, the production of high-quality and high-grade vanadium-aluminum intermediate alloys for aerospace is still blank, the potential requirements of the market cannot be met, and particularly, the implementation of large airplane projects in China urgently needs to develop and produce high-quality and high-performance high-grade vanadium-aluminum intermediate alloys. Therefore, the vanadium-aluminum intermediate alloy can replace the import in China, and the vanadium-aluminum intermediate alloy is introduced into the titanium alloy market, so that the vanadium-aluminum intermediate alloy must play a strong role in promoting the development of the titanium industry in China. In particular, because the high-grade vanadium-aluminum intermediate alloy is mainly used for manufacturing aircrafts, China needs to strengthen research and development production and break the material bottleneck of aircraft manufacturing. Most of the vanadium-aluminum alloys produced at present in China have the following defects:

1. the impurity elements in the alloy components are higher, such as O, N, C, S, P, and the elements can have great influence on the performance of the titanium alloy. O, N, C is alpha phase stable element, and forms gap solid solution alloy and metal compound phase with titanium, which reduces the plasticity of titanium alloy; s, P is a harmful element that can cause brittleness of the titanium alloy.

2. The alloy has poor compositional uniformity, and the compositional ratio is unstable, and segregation occasionally occurs. This occasional segregation, if used to manufacture aerospace vehicles, can be a fatal factor in one hundred percent and does not guarantee "unjustifiable" quality requirements.

Disclosure of Invention

The invention aims to provide a smelting process and a vacuum device for reducing oxygen and nitrogen contents of an aerospace grade high-vanadium aluminum alloy, so that main elements of a smelted intermediate alloy are uniformly distributed, the contents of impurity elements such as oxygen, nitrogen and the like are greatly reduced, and the aerospace grade vanadium aluminum alloy with stable quality can be prepared. The specific technical scheme is as follows:

a smelting process for reducing oxygen and nitrogen contents of an aerospace grade high-vanadium aluminum alloy is characterized by comprising the following steps:

step 1), preparing materials: selecting pure vanadium pentoxide, pure aluminum powder, pure fluorite powder and potassium chlorate with proper granularity according to the set mass percentage ratio of the materials to form materials before mixing, and drying;

step 2), mixing and charging reaction: drying the V₂100kg of vanadium pentoxide, 59.6kg of aluminum powder, 15kg of fluorite powder and 0.5kg of potassium chlorate are put into a mixer and mixed for 30-50 minutes at 120-130 ℃ to form uniformly mixed materials, then the uniformly mixed materials are put into a crucible (5) to form a furnace charge (6), a small amount of magnesium chips are ignited and then put into the crucible to ignite the furnace charge, and the aluminothermic reaction is carried out for 3V₂O₅+10Al＝6V+5Al₂O₃；

Step 3), cooling: excessive aluminum and a reactant vanadium form a vanadium-aluminum alloy, a vacuum device is covered on the upper part of a crucible (5) for airtight connection at the final stage of smelting, a vacuum mechanical pump (1) and a vacuum Roots pump (2) are started, a control valve (3) is opened at the same time for vacuumizing to form negative pressure in the crucible (5), and the control valve (3) is closed after the vacuum degree is less than or equal to 3Pa to naturally cool a reacted material (6) in the crucible (5);

step 4), dismantling the furnace and weighing: after the materials (6) after the crucible reaction are completely reacted and crystallized, cooling for 2-4 hours and then removing the furnace; if the vanadium-aluminum alloy is smelted in hot weather, the cooling time is prolonged to more than 4-5 hours; weighing and recording the discharged vanadium-aluminum alloy block;

step 5), sand blasting and finishing: carrying out sand blasting treatment on the cooled vanadium-aluminum alloy block, cleaning slag and furnace ash attached to the surface, polishing the surface of the vanadium-aluminum alloy block by using a grinding machine to grind an oxide layer and surface defects, and blowing the surface by using high-pressure air until the natural color of the metal is exposed, and placing the vanadium-aluminum alloy block far away from the grinding machine;

step 6), crushing: crushing the polished vanadium-aluminum alloy blocks into large blocks, adding the large blocks into a crusher for further crushing and refining, and sieving the large blocks by using a sieve with the specification of 6mm, wherein the vanadium-aluminum alloy blocks larger than 6mm need to be crushed again; immediately barreling, weighing and marking batch numbers for the vanadium-aluminum alloy blocks sieved in the same batch;

step 7), selecting materials: manually picking out impurities, foreign matters or oxides from the vanadium-aluminum alloy blocks under the crushed screens;

step 8), finished product inspection and warehousing: and (4) performing selective inspection on the picked vanadium-aluminum alloy blocks by inspectors according to 5 percent of the vanadium-aluminum alloy blocks in the batch, judging that the vanadium-aluminum alloy blocks are qualified and warehousing the vanadium-aluminum alloy blocks without finding impurities, foreign matters and oxides.

Secondly, the vacuum device for the melting process of the aerospace grade high vanadium aluminum alloy for reducing the oxygen and nitrogen content as claimed in claim 1, wherein the vacuum mechanical pump (1), the vacuum roots pump (2), the control valve (3) and the crucible cover plate (4) are connected in sequence through pipelines; wherein the crucible cover plate (4) is connected with the crucible (5) in an airtight manner; when the vacuum mechanical pump (1) and the vacuum roots pump (2) are used for vacuumizing, the control valve (3) is opened, gas existing in the crucible (5) is pumped out, the control valve (3) is closed after the proper vacuum degree is achieved, the negative pressure vacuum state is maintained, and the materials (6) after reaction in the crucible are isolated from the outside air; the crucible cover plate (4) is a flange with threads and is screwed tightly and hermetically connected with the threads processed on the outer edge of the upper opening of the crucible (5).

The aerospace grade vanadium-aluminum alloy prepared by the process has the technical effects that:

1. the content of impurity elements such as carbon, silicon, nitrogen, iron, phosphorus, sulfur and the like is reduced by selecting high-purity raw materials; and (3) uniformly mixing the dried materials in a mixer before reaction, preventing components from segregating, and ensuring the element distribution uniformity.

2. A vacuum device is additionally arranged and started at the last stage of smelting, so that the air in the crucible after reaction can be effectively discharged, oxygen and nitrogen in the air are prevented from permeating into the material, and the oxygen and nitrogen content in the finished product is greatly reduced; in addition, impurity elements such as carbon, phosphorus, sulfur and the like in the air can be extracted, the content of other impurities in the finished product can be reduced, and the quality requirement of the aerospace-grade vanadium-aluminum alloy is met.

3. Compared with the traditional process, the smelting process of the invention has the advantages that the content of the impurity components of the vanadium-aluminum alloy is obviously reduced by O, N elements which respectively reach 91.48% and 81.75% by adding the vacuum device, and the technical effect is very obvious. In addition, the content of C, S and P is effectively reduced.

Drawings

FIG. 1 is a schematic structural diagram of a vacuum apparatus according to the present invention.

In the figure, 1-vacuum mechanical pump, 2-vacuum roots pump, 3-control valve, 4-crucible cover plate, 5-crucible, 6-material.

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the accompanying drawings.

Fig. 1 is a schematic structural view of the vacuum apparatus of the present invention. The vacuum device is formed by sequentially connecting a vacuum mechanical pump 1, a vacuum roots pump 2, a control valve 3 and a crucible cover plate 4 through pipelines; wherein the crucible cover plate 4 is connected with the crucible 5 in an airtight manner; when the vacuum mechanical pump 1 and the vacuum roots pump 2 are vacuumized, the control valve 3 is opened, gas existing in the crucible 5 is pumped out, the control valve 3 is closed after the proper vacuum degree is achieved, the negative pressure vacuum state is maintained, and the reacted material 6 in the crucible is isolated from the outside air. The further improvement is that the crucible cover plate 4 is a flange with screw threads and is screwed and hermetically connected with the screw threads processed on the outer edge of the upper opening of the crucible 5, so that the airtight effect is optimal. The crucible 5 is preferably a copper crucible.

Now, in this embodiment, 85 mass percent of vanadium in the high vanadium-aluminum alloy is set as 85%, and the balance is aluminum AL. The process ratio is as follows: 100kg of vanadium pentoxide, 59.6kg of aluminum powder and 15kg of fluorite powder CaF₂0.5kg of potassium chlorate. The specific implementation steps are as follows:

step 1), preparing materials: selecting 100kg of pure vanadium pentoxide, 59.6kg of pure aluminum powder, 15kg of pure fluorite powder and 0.5kg of potassium chlorate with proper granularity according to the set mass percentage ratio of the materials to form the materials before mixing; weighing the materials with the error of not more than +/-5 g in each part, and recording the materials in a production record table;

step 2), mixing and charging reaction: the baked V₂O₅、CaF₂Weighing aluminum powder according to a process proportion (weight of a single furnace), putting the aluminum powder into a mixing container, mixing the aluminum powder for 30-50 minutes at the temperature of 120-130 ℃, and recording the temperature and the mixing time; then the evenly mixed materials are put into a crucible 5 to form furnace charge, a small amount of 20g magnesium chips are put into the crucible 5 after being ignited to ignite the furnace charge, and the aluminothermic reaction is carried out for 3V₂O₅+10Al＝6V+5Al₂O₃(ii) a The crucible (5) is a copper crucible.

Step 3), vacuum cooling: excessive aluminum and a reactant vanadium form a vanadium-aluminum alloy, a vacuum device is additionally arranged on the upper part of a crucible 5 to be hermetically connected at the last stage of smelting, a vacuum mechanical pump 1 and a vacuum roots pump 2 are started, a control valve 3 is opened to vacuumize to form negative pressure in the crucible 5, and the control valve 3 is closed after the vacuum degree is less than or equal to 3Pa to naturally cool a reacted material 6 in the crucible 5;

step 4), dismantling the furnace and weighing: after the materials in the furnace completely react and are crystallized, the furnace is disassembled after being cooled for 3 hours; when the vanadium-aluminum alloy is smelted in hot weather, the cooling time is prolonged to more than 4 hours; weighing the vanadium-aluminum alloy discharged from the furnace, calculating the yield and recording the yield into a table;

step 5), sand blasting and finishing: carrying out sand blasting treatment on the cooled vanadium-aluminum alloy block, and removing slag and furnace ash attached to the surface; then, polishing the surface of the material by using a grinding machine, further removing an oxide layer and surface defects, and blowing the surface by using high-pressure air to expose the natural color of the metal; the polished material is placed far away from a grinding machine, so that dust of a grinding wheel is prevented from falling on the material;

step 6), crushing: firstly, crushing a vanadium-aluminum alloy block into large blocks, adding the large blocks into a crusher for further crushing and refining, and then sieving the large blocks by using a sieve with the specification of 6mm, wherein the material with the size of more than 6mm needs to be crushed again; putting the same batch of vanadium-aluminum alloy into a crushing chamber for crushing, immediately barreling the sieved crushed materials, weighing and marking batch numbers;

step 7), selecting materials: for undersize crushed aggregates, impurities, foreign matters or oxides are manually picked out, and a sticky slag layer, an oxidation layer and foreign matters cannot be attached to the metal surface;

step 8), finished product inspection and warehousing: the sorted crushed aggregates finished products can be put in storage after being checked by inspectors; and (4) performing sampling inspection by inspectors according to 5 percent of the finished crushed aggregates, judging that the crushed aggregates are unqualified if impurities, foreign matters or oxides are found, and picking up the crushed aggregates again until the crushed aggregates are qualified.

The content of impurity components of vanadium-aluminum alloy in the conventional process, the melting process (without adding a vacuum device) of the embodiment and the embodiment after adding the vacuum device is compared, as shown in table 1 "content comparison table of impurity components of vanadium-aluminum alloy in different production processes". As can be seen from table 1, compared with the conventional process, the embodiments of the present invention respectively reduce O, N, C, S, P by 91.48%, 81.75%, 48.75%, 86.86% and 78.89%, and have significant technical effects. In particular, the technical effect of reducing the removal O, N, which is pursued by the invention, is better.

TABLE 1 comparison table of contents of impurity components in V-Al alloy in different production processes