Nickel-yttrium intermediate alloy and preparation method thereof

Abstract

The invention discloses a nickel-yttrium intermediate alloy and a preparation method thereof. The nickel-yttrium intermediate alloy comprises the following components in percentage by weight: 91-93% of Ni; and 7%-9% of Y. According to the nickel-yttrium intermediate alloy with the Y content being 7%-9%, the problem that the Y element is difficult to add when the nickel-based alloy containing the Y element is smelted is successfully solved, and it is verified through the follow-up smelting process that the metal element Y in the Inconel 602CA nickel-based alloy meets the requirement of ASME SB168. Meanwhile, after the Ni-Y intermediate alloy is added, the yield of the Y element reaches 80%-85%, and a technical guarantee is provided for localization of the nickel-based alloy containing the metal yttrium.

Description

Technical Field

[0001] The invention belongs to the technical field of metal material processing, and in particular relates to a nickel-yttrium master alloy and a preparation method thereof. Background Art

[0002] Nickel-based alloy N06025, full name Inconel602CA, has excellent high temperature performance and excellent corrosion resistance. Its good oxidation resistance, corrosion resistance and high temperature strength make it an ideal material for aerospace, energy and chemical industries. At the same time, it is also widely used in metal heating treatment industries. The alloy has the characteristics of good thermal stability and excellent mechanical properties. Its chemical composition contains 0.05% to 0.12% of the metal element yttrium. As a rare earth element, metal yttrium is usually added to the alloy to improve its high temperature oxidation resistance and high temperature thermal stability. However, the outermost layer of the yttrium nucleus has only one electron, which is highly active and easily oxidized to form non-metallic compounds with high melting point, low density and stable structure. These non-metallic compounds float up through the buoyancy of the metal liquid or are adsorbed on the crucible wall, and it is difficult to enter the alloy matrix. During the smelting process, metal yttrium is added in the form of pure metal, and the yield is almost zero. Because it is easily oxidized during the smelting process to form oxides with high melting point and low density, and floats up through the metal liquid or is adsorbed on the crucible wall, it is difficult to remain in the alloy matrix, making the chemical composition of the master alloy unqualified. Summary of the invention

[0003] In order to solve the above problems existing in the prior art, the present invention provides a nickel-yttrium master alloy and a preparation method thereof. The technical problem to be solved by the present invention is achieved by the following technical solutions:

[0004] A nickel-yttrium master alloy comprises the following components in weight percentage: Ni: 91%-93%; Y: 7%-9%.

[0005] Another embodiment of the present invention provides a method for preparing a nickel-yttrium master alloy, comprising:

[0006] Step 1: Purify the electrolytic nickel by vacuum induction melting to reduce the oxygen content in the electrolytic nickel;

[0007] Step 2: The purified electrolytic nickel and metal yttrium are mixed according to the following weight percentages: Ni: 91% to 95%; Y: 5% to 9%;

[0008] Step 3: Load the electrolytic nickel and metallic yttrium into a vacuum induction furnace for vacuum induction melting to obtain a nickel-yttrium master alloy.

[0009] Furthermore, in step 1:

[0010] The electrolytic nickel is purified by removing oxygen content in the electrolytic nickel using a nickel-magnesium alloy and carbon, wherein the content of the nickel-magnesium alloy accounts for 0.05% to 0.1% of the electrolytic nickel content; and the content of carbon accounts for 0.01% to 0.03% of the electrolytic nickel content.

[0011] Furthermore, the nickel-magnesium alloy is Ni30Mg.

[0012] Furthermore, the step 3 comprises:

[0013] Step 3.1: Load the electrolytic nickel into the furnace and the metal yttrium into the charging bin, and evacuate the furnace until the vacuum degree is ≤10 -1 Pa;

[0014] Step 3.2: Start to supply electricity, first melt the electrolytic nickel in the furnace into liquid, then fill the furnace with inert gas argon, and when the pressure in the furnace is 0.9-0.95MPa, add metal yttrium;

[0015] Step 3.3: After all the materials in the furnace are completely cleared, electromagnetic stirring is performed for 2 to 3 minutes, and then pouring is performed in the furnace after the temperature in the furnace reaches 1320 to 1350° C., and then the furnace is cooled for 25 to 35 minutes before being taken out of the furnace to obtain a nickel-yttrium master alloy ingot;

[0016] Step 3.4: Surface treatment is performed on the nickel-yttrium master alloy ingot, and the ingot is crushed to obtain the nickel-yttrium master alloy.

[0017] Beneficial effects of the present invention:

[0018] 1. The present invention prepares a nickel-yttrium master alloy with a Y content of 7% to 9%, which successfully solves the problem that the Y element is difficult to add when the nickel-based alloy containing the element Y is smelted. After subsequent smelting process verification, the metal element Y in the Inconel602CA nickel-based alloy meets the requirements of ASME SB168. At the same time, after the Ni-Y master alloy is added, the Y element recovery rate reaches 80% to 85%, which provides technical guarantee for the localization of nickel-based alloys containing metal yttrium;

[0019] 2. The nickel-yttrium master alloy obtained by vacuum induction melting can form a stable Ni-Y metal compound, and the master alloy has a density comparable to that of the nickel-based alloy matrix and a stable structure. Compared with the direct addition of pure metal Y, the addition of the Ni-Y master alloy effectively solves the loss of the Y element and ensures the qualified rate of the chemical composition of the smelted alloy.

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1A test report of the yttrium content in the nickel-yttrium master alloy ingot prepared in Example 1;

[0022] Figure 2 This is a composition test report of the Inconel602CA nickel-based alloy prepared from the nickel-yttrium master alloy in Example 1. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0024] Example 1

[0025] The embodiment of the present invention provides a nickel-yttrium master alloy, comprising the following components in weight percentage: Ni: 91% to 93%; Y: 7% to 9%.

[0026] The nickel-yttrium master alloy with a Y content of 7% to 9% successfully solves the problem of difficulty in adding the Y element during the smelting of the nickel-based alloy Inconel602CA containing the element Y, thereby ensuring the smelting pass rate of the nickel-based alloy containing the Y element.

[0027] Example 2

[0028] The embodiment of the present invention provides a method for preparing a nickel-yttrium master alloy with a specification of Ф120mm×L, which specifically comprises the following steps:

[0029] Step 1: Purify the raw material electrolytic nickel by vacuum induction melting to reduce the oxygen content in the electrolytic nickel.

[0030] Using a vacuum induction furnace, nickel-magnesium master alloy and spectral carbon to remove oxygen from Ni9996 electrolytic nickel, the electrolytic nickel is purified, and the oxygen content is reduced from 50ppm before purification to less than 10ppm after purification. At the same time, the Mg remaining in the electrolytic nickel reacts preferentially with oxygen during the smelting process of the finished product, thereby further reducing the oxidation and burning of Y and increasing the Y smelting yield. This step reduces the oxygen content in the raw materials to an extremely low level in advance, reducing the oxygen in the raw materials.

[0031] The specific ratio in the embodiment of the present invention is shown in Table 1:

[0032] Table 1 Component ratio of electrolytic nickel purification in Example 1

[0033]

[0034] Step 2: Weigh the purified electrolytic nickel and metallic yttrium and mix them according to Table 2; the electrolytic nickel and metallic yttrium can form a new metal compound (eutectic structure) with a low melting point, a density close to that of the alloy matrix, and a stable structure under this ratio, and participate in alloying in the subsequent nickel-based alloy smelting in the form of a stable metal compound Ni-Y.

[0035] Table 2 Ingredients for preparing nickel-yttrium master alloy in Example 1

[0036]

[0037] Step 3: The electrolytic nickel and metallic yttrium in step 2 are placed into a 25kg vacuum induction furnace for vacuum induction melting to obtain a nickel-yttrium master alloy.

[0038] Specifically, step 3 includes the following contents:

[0039] Step 3.1: Load 18.5 kg of electrolytic nickel into the furnace and 1.5 kg of metal yttrium into the charging bin, and evacuate the vacuum in the vacuum induction furnace to a vacuum degree of ≤10 -1 Pa.

[0040] Step 3.2: Then start to supply power to increase the temperature, and make the power of the vacuum induction furnace reach 30-35kw at a power of 3-5kw / min, melt the electrolytic nickel in the furnace into liquid, and then fill the furnace with inert gas argon. When the pressure in the furnace is displayed as 0.9-0.95MPa, add metal yttrium. In the smelting process, the inert gas argon is filled to increase the surface pressure of the liquid, prevent the liquid from boiling excessively, and reduce the direct burning of metal yttrium; at the same time, it can also improve the negative pressure environment of the vacuum melting chamber, and again prevent the volatilization and oxidation of the high vapor pressure element yttrium.

[0041] Step 3.3: After all the materials in the furnace are completely cleared, electromagnetic stirring is performed for 2 to 3 minutes, and then pouring is performed in the furnace after the temperature in the furnace reaches 1320 to 1350°C, and then the furnace is cooled for 30 minutes before being taken out of the furnace. After demolding, a nickel-yttrium master alloy ingot with a diameter of 120 mm is obtained, and the yttrium content of the nickel-yttrium master alloy ingots from the two furnaces before and after is tested. The test results are as follows: Figure 1 As shown in Table 3:

[0042] Table 3 Yttrium content in nickel-yttrium master alloy ingot

[0043] Ingot number Y(W / %) NiY-202225-019-1 6.16 NiY-202225-019-2 7.37

[0044] Step 3.4: The nickel-yttrium master alloy ingot is cut off from the head and tail, and the surface is peeled, and then cleaned with alcohol and baked at low temperature in an electric furnace to remove the sawing liquid remaining during sawing, and finally broken into pieces with a size of ≤50×50mm to obtain a nickel-yttrium master alloy. By removing the contact surface between the liquid and the metal mold and the slightly oxidized parts during the casting process of the master alloy, the introduction of oxygen elements during the smelting process is reduced again, and the master alloy is broken into pieces, the reaction contact area is increased, the alloying time is reduced, and the probability of easy secondary oxidation of metal yttrium in the metal is reduced.

[0045] The prepared nickel-yttrium master alloy and vacuum induction melting process are used to prepare Inconel602CA nickel-based alloy. Specifically, a 500kg vacuum induction furnace is used for melting, and the mold adopts a mold with a specification of Ф260mm×L. The total feed amount is 450kg, of which 540g of nickel-yttrium master alloy is fed, and the feed amount and melting process of other raw materials are the same as those of the prior art. The test results of the finally prepared Inconel602CA nickel-based alloy are as follows: Figure 2 As shown, the report shows that the metallic yttrium content reaches 0.1% and the final yield is 83%.

[0046] Example 3

[0047] The embodiment of the present invention provides a method for preparing a nickel-yttrium master alloy with a specification of Ф230mm×L, which specifically includes the following steps:

[0048] Step 1: Purify the raw material electrolytic nickel by vacuum induction melting to reduce the oxygen content in the electrolytic nickel.

[0049] Using a vacuum induction furnace, nickel-magnesium master alloy and spectral carbon to remove oxygen from Ni9996 electrolytic nickel, the electrolytic nickel is purified, and the oxygen content is reduced from 50ppm before purification to less than 10ppm after purification. At the same time, the Mg remaining in the electrolytic nickel reacts preferentially with oxygen during the smelting process of the finished product, thereby further reducing the oxidation and burning of Y and increasing the Y smelting yield. This step reduces the oxygen content in the raw materials to an extremely low level in advance, reducing the oxygen in the raw materials.

[0050] The specific ratio in the embodiment of the present invention is shown in Table 4:

[0051] Table 4 Component ratio of electrolytic nickel purification in Example 2

[0052]

[0053] Step 2: Weigh the purified electrolytic nickel and metallic yttrium and mix them according to Table 2; the electrolytic nickel and metallic yttrium can form a new metal compound (eutectic structure) with a low melting point, a density close to that of the alloy matrix, and a stable structure under this ratio, and participate in alloying in the subsequent nickel-based alloy smelting in the form of a stable metal compound Ni-Y.

[0054] Table 5 Ingredients for preparing nickel-yttrium master alloy in Example 2

[0055]

[0056] Step 3: The electrolytic nickel and metallic yttrium in step 2 are placed into a 200kg vacuum induction furnace for vacuum induction melting to obtain a nickel-yttrium master alloy.

[0057] Specifically, step 3 includes the following contents:

[0058] Step 3.1: Load 148kg of electrolytic nickel into the furnace and 12kg of metal yttrium into the charging bin, and evacuate the vacuum in the vacuum induction furnace to a vacuum degree of ≤10 -1 Pa.

[0059] Step 3.2: Then start to supply power to increase the temperature, and make the power of the vacuum induction furnace reach 120-135kw at a power of 3-5kw / min, melt the electrolytic nickel in the furnace into liquid, and then fill the furnace with inert gas argon. When the pressure in the furnace is displayed as 0.9-0.95MPa, add metal yttrium. In the smelting process, the inert gas argon is filled to increase the surface pressure of the liquid, prevent the liquid from boiling excessively, and reduce the direct burning of metal yttrium; at the same time, it can also improve the negative pressure environment of the vacuum melting chamber, and again prevent the volatilization and oxidation of the high vapor pressure element yttrium.

[0060] Step 3.3: After all the materials in the furnace are completely cleared, electromagnetic stirring is performed for 2 to 3 minutes, and then pouring is performed in the furnace after the temperature in the furnace reaches 1320 to 1350°C, and then the furnace is cooled for 30 minutes before being taken out of the furnace. After demolding, a 230mm Ф nickel-yttrium master alloy ingot is obtained, and the yttrium content of the nickel-yttrium master alloy ingots from the two furnaces before and after is tested. The test results are as follows: Figure 1 As shown in Table 2:

[0061] Table 2 Yttrium content in nickel-yttrium master alloy ingot

[0062] Ingot number Y(W / %) NiY-2023200-012-1 6.56 NiY-2023200-012-2 6.82

[0063] Step 3.4: The nickel-yttrium master alloy ingot is cut off from the head and tail, and the surface is peeled, and then cleaned with alcohol and baked at low temperature in an electric furnace to remove the sawing liquid remaining during sawing, and finally broken into pieces with a size of ≤50×50mm to obtain a nickel-yttrium master alloy. By removing the contact surface between the liquid and the metal mold and the slightly oxidized parts during the casting process of the master alloy, the introduction of oxygen elements during the smelting process is reduced again, and the master alloy is broken into pieces, the reaction contact area is increased, the alloying time is reduced, and the probability of easy secondary oxidation of metal yttrium in the metal is reduced.

[0064] The prepared nickel-yttrium master alloy and vacuum induction melting process are used to prepare the Inconel602CA nickel-based alloy. Specifically, a 2.5-ton vacuum induction furnace is used for melting, and the mold adopts a mold with a specification of Ф440mm×L. The total feed amount is 2000kg, of which 32kg of nickel-yttrium master alloy is fed, and the feed amount and smelting process of other raw materials are the same as the prior art. The Inconel602CA nickel-based alloy finally prepared is tested, and the metal yttrium content reaches 0.09%, which meets the requirements of ASME SB168 (yttrium content 0.05% to 0.12%), and the final yield is ≥80%.

[0065] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A nickel-yttrium master alloy, characterized in that: The invention comprises the following components in weight percentage: Ni: 91% to 93%; Y: 7% to 9%.

2. A method for preparing a nickel-yttrium master alloy as claimed in claim 1, characterized in that: include: Step 1: Purify the electrolytic nickel by vacuum induction melting to reduce the oxygen content in the electrolytic nickel; Step 2: The purified electrolytic nickel and metal yttrium are mixed according to the following weight percentages: Ni: 91% to 95%; Y: 5% to 9%; Step 3: Load the electrolytic nickel and metallic yttrium into a vacuum induction furnace for vacuum induction melting to obtain a nickel-yttrium master alloy.

3. The method for preparing a nickel-yttrium master alloy according to claim 2, characterized in that: In step 1: The electrolytic nickel is purified by removing oxygen content in the electrolytic nickel using a nickel-magnesium alloy and carbon, wherein the content of the nickel-magnesium alloy accounts for 0.05% to 0.1% of the electrolytic nickel content; and the content of carbon accounts for 0.01% to 0.03% of the electrolytic nickel content.

4. The method for preparing a nickel-yttrium master alloy according to claim 3, characterized in that: The nickel-magnesium alloy is Ni30Mg.

5. The method for preparing a nickel-yttrium master alloy according to claim 1, characterized in that: The step 3 comprises: Step 3.1: Load the electrolytic nickel into the furnace and the metal yttrium into the charging bin, and evacuate the furnace until the vacuum degree is ≤10 -1 Pa; Step 3.2: Start to supply electricity, first melt the electrolytic nickel in the furnace into liquid, then fill the furnace with inert gas argon, and when the pressure in the furnace is 0.9-0.95MPa, add metal yttrium; Step 3.3: After all the materials in the furnace are completely cleared, electromagnetic stirring is performed for 2 to 3 minutes, and then pouring is performed in the furnace after the temperature in the furnace reaches 1320 to 1350° C., and then the furnace is cooled for 25 to 35 minutes before being taken out of the furnace to obtain a nickel-yttrium master alloy ingot; Step 3.4: Surface treatment is performed on the nickel-yttrium master alloy ingot, and the ingot is crushed to obtain the nickel-yttrium master alloy.

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