阅读说明：本技术 一种高纯钒锭的var熔炼方法 (VAR smelting method of high-purity vanadium ingot ) 是由 张利军 刘娣 焦勇 周中波 刘小花 吴天栋 薛祥义 于 2019-11-05 设计创作，主要内容包括：一种高纯钒锭的VAR熔炼方法,采用油压机高纯钒压制成数块电极块,再将这些电极块焊接成自耗电极。将自耗电极采用真空自耗熔炼方法进行熔炼,得到一次锭,再进行二次熔炼,扒皮、切除冒口,获得成品铸锭。本发明不但实现了纯钒锭的洁净化、内部及表面质量好的目的,而且真空自耗熔炼方法技术成熟,工艺自动化程度高、操作简单,成本低,可实现工业规模铸锭的制备,为后续热加工及机械加工提供良好的坯料。(A VAR smelting method of high-purity vanadium ingots is characterized in that high-purity vanadium is pressed into a plurality of electrode blocks by an oil press, and then the electrode blocks are welded into consumable electrodes. And smelting the consumable electrode by adopting a vacuum consumable smelting method to obtain a primary ingot, then carrying out secondary smelting, peeling and cutting off a riser to obtain a finished product cast ingot. The method not only realizes the purposes of clean and clean pure vanadium ingot and good internal and surface quality, but also has mature vacuum consumable melting method technology, high process automation degree, simple operation and low cost, can realize the preparation of industrial-scale ingot casting, and provides good blank for subsequent hot processing and mechanical processing.)

1. A VAR smelting method of high-purity vanadium ingots is characterized by comprising the following steps:

step 1: pressing high-purity vanadium with the purity of 99.99 percent into a plurality of electrode blocks, and welding the plurality of electrode blocks into a consumable electrode;

step 2: carrying out primary smelting on the consumable electrode in the step 1 by adopting a vacuum consumable smelting method to obtain a primary ingot; wherein, the primary smelting current is 2.0-4.0 KA, the smelting voltage is 24-32V, and the arc stabilizing current is: direct current is 2-3A;

and step 3: performing secondary smelting by using the primary ingot obtained in the step 2 as a consumable electrode to obtain a secondary ingot;

and 4, step 4: and (4) peeling the secondary cast ingot in the step (3), detecting a flaw, and then cutting off a riser to obtain the high-purity vanadium ingot.

2. The VAR smelting method of high-purity vanadium ingots according to claim 1, characterized in that in the step 1, welding is carried out in a vacuum plasma welding box, and the welding vacuum degree is less than or equal to 5.0 x 10 degrees Pa.

3. The VAR smelting method of high-purity vanadium ingots according to claim 1, characterized in that in the step 2, the crucible ratio D/D of primary smelting is 0.70-0.80, wherein D is the electrode diameter and D is the crucible diameter.

4. The VAR smelting method of the high-purity vanadium ingot according to claim 1, characterized in that in step 3, the secondary smelting current is 2.5-5.0 KA, the smelting voltage is 24-34V, and the arc stabilizing current is as follows: direct current is 3-4A, and the cooling time is more than or equal to 2 h.

5. The VAR smelting method of high-purity vanadium ingots according to claim 1, characterized in that in the step 3, the crucible ratio D/D of the secondary smelting is 0.70-0.75.

6. The VAR smelting method of the high-purity vanadium ingot according to claim 1, characterized in that in the steps 2 and 3, a large current is adopted to make a molten pool sound during smelting, and then the smelting current is reduced to a low smelting current until the smelting is finished, wherein the difference between the large current and the low smelting current is 0.2-0.5 KA.

Technical Field

The invention belongs to the field of new material preparation, and relates to a VAR smelting method of a high-purity vanadium ingot.

Background

Vanadium is a silver-grey metal. The vanadium has a density of 6.11g/cm3, a melting point of 1919 + -2 ℃, and belongs to the group of high-melting rare metals. Pure vanadium has good plasticity, and can be rolled into sheets, foils and drawn into wires at normal temperature. But the chemical activity is strong, the performance is very sensitive to the content of impurities, and a small amount of impurities, particularly interstitial elements such as carbon, oxygen, nitrogen, hydrogen and the like, can reduce the plasticity of the vanadium and increase the hardness and brittleness.

At present, the global environment is confronted with the crises of environmental pollution, climate warming, energy shortage and the like, so that various countries join in a row for searching new sustainable development energy. Nuclear power has attracted continuous attention from countries around the world with its outstanding advantages of cleanliness, high efficiency, low resource consumption, etc. Controllable nuclear fusion is one of the directions of human energy development. The vanadium and the alloy thereof have the advantages of low activation, high thermal conductivity, high creep strength, low thermal expansion, excellent mechanical property and irradiation swelling resistance, capability of bearing heat load 4-7 times higher than that of stainless steel and the like, are not only preferred low-activation structural materials of the first wall cladding of the nuclear fusion reactor, but also can be applied to the fields of aviation national defense, high-temperature environment and the like. Therefore, obtaining high-purity vanadium ingots is the basis for obtaining structural materials.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a VAR smelting method of high-purity vanadium ingots, which has the advantages of low cost, mature technology, simple operation and no air holes inside.

In order to achieve the purpose, the invention adopts the technical scheme that:

a VAR smelting method of high-purity vanadium ingots comprises the following steps:

step 1: pressing high-purity vanadium with the purity of 99.99 percent into a plurality of electrode blocks, and welding the plurality of electrode blocks into a consumable electrode;

step 2: carrying out primary smelting on the consumable electrode in the step 1 by adopting a vacuum consumable smelting method to obtain a primary ingot; wherein, the primary smelting current is 2.0-4.0 KA, the smelting voltage is 24-32V, and the arc stabilizing current is: direct current is 2-3A;

and step 3: performing secondary smelting by using the primary ingot obtained in the step 2 as a consumable electrode to obtain a secondary ingot;

and 4, step 4: and (4) peeling the secondary cast ingot in the step (3), detecting a flaw, and then cutting off a riser to obtain the high-purity vanadium ingot.

The further improvement of the invention is that in the step 1, the welding is carried out in a vacuum plasma welding box, and the welding vacuum degree is less than or equal to 5.0 multiplied by 10 degrees Pa.

The invention is further improved in that in the step 2, the crucible ratio D/D of primary smelting is 0.70-0.80, wherein D is the electrode diameter, and D is the crucible diameter.

The further improvement of the invention is that in the step 3, the secondary smelting current is 2.5-5.0 KA, the smelting voltage is 24-34V, and the arc stabilizing current is as follows: direct current is 3-4A, and the cooling time is more than or equal to 2 h.

The invention is further improved in that in the step 3, the crucible ratio D/D of the secondary smelting is 0.70-0.75.

The further improvement of the invention is that in the step 2 and the step 3, after the molten pool is sound by adopting large current in the smelting process, the low smelting current is reduced until the smelting is finished, wherein the difference between the large current and the low smelting current is 0.2-0.5 KA.

Compared with the prior art, the invention has the beneficial effects that: the invention adopts a vacuum consumable arc melting method to prepare the high-purity vanadium ingot, and the sputtering generation is reduced because of selecting smaller melting current and arc stabilizing current, the height of the ingot crown is controlled within 50mm, and the surface quality of the ingot is improved. The method not only realizes the purposes of cleaning the pure vanadium ingot (V is more than or equal to 99.85%) and good internal and surface quality, but also has the advantages of mature technology of the vacuum consumable melting method, high process automation degree, simple operation and low cost, can realize the preparation of industrial-scale cast ingots, and provides good blanks for subsequent hot processing and mechanical processing.

Furthermore, because the melting point of vanadium is higher, the melting bath is well-done slowly when the smelting is started, and the melting bath is well-done by adopting large current in the actual smelting operation process, and then the melting bath is reduced to lower smelting current until the smelting is finished.

Furthermore, in the invention, the proper crucible ratio is controlled, because the crucible ratio is too small in the smelting process, in order to ensure the soundness of a molten pool in the smelting process, high-current smelting is adopted, the arc length is reduced as much as possible in the smelting process, and because the smelting speed is high, gas generated in the smelting process cannot be discharged in time, subcutaneous gas holes and internal gas holes are formed, and the quality of cast ingots is influenced. When the crucible ratio is too large, side arcs can be generated, the crucible can be punctured for a long time, and safety accidents are caused.

Detailed Description

The present invention will now be described in further detail with reference to examples, wherein% means mass% in the present invention.

The invention relates to a VAR smelting method of a high-purity vanadium ingot, which comprises the following steps:

step 1: dendritic high-purity vanadium (V99.99%) prepared by a salt electrolysis refining method is used as a raw material.

Step 2: pressing the high-purity vanadium obtained in the step 1 into a plurality of electrode blocks by using an oil press, and welding the electrode blocks into consumable electrodes. Wherein, the welding is carried out in a vacuum plasma welding box, and the welding vacuum degree is less than or equal to 5.0 multiplied by 10 degrees Pa.

And step 3: and (3) smelting the consumable electrode in the step (2) by adopting a vacuum consumable smelting method to obtain a primary ingot. Wherein, the crucible ratio D/D (electrode diameter/crucible diameter) of smelting is 0.70-0.80, the smelting current is 2.0-4.0 KA, the smelting voltage is 24-32V, and the arc stabilizing current is as follows: direct current, 2-3A, and the cooling time is more than or equal to 1 h.

And 4, step 4: and (4) performing secondary smelting by using the primary ingot obtained in the step (3) as a consumable electrode to obtain a secondary ingot. Wherein the crucible ratio D/D of the secondary smelting is 0.70-0.75, the smelting current is 2.5-5.0 KA, the smelting voltage is 24-34V, the arc stabilizing current is direct current and is 3-4A, and the cooling time is not less than 2 h.

And 5: and (4) peeling the secondary cast ingot in the step (4), detecting flaws, and then cutting off a riser to obtain a finished cast ingot.

In steps 3 and 4 of the invention, after the high current is adopted to make the molten pool sound in the smelting operation process, the smelting current is reduced to a lower value until the smelting is finished. Wherein the difference between the large current and the low melting current is 0.2-0.5 KA.