A method for producing an aluminum niobium master alloy for titanium alloy smelting

Abstract

The application relates to a preparation method of an aluminum niobium intermediate alloy for titanium alloy smelting, which comprises the following steps: 1) raw materials including main raw material niobium pentoxide, reducing agent metal aluminum powder, slag forming agent calcium oxide and calcium fluoride, and the above raw materials are mixed and pretreated; 2) the mixture of step 1) is put into a reaction device, and a heat supplement agent is added; 3) the material is ignited to make the material have an aluminothermic combustion reaction; 4) after the reaction is finished, the material is slowly cooled in the original position, and then is naturally cooled to room temperature; and 5) after the cooling is finished, the slag and the gold are separated, and the aluminum niobium intermediate alloy is obtained. The application considers the product quality, low cost, practicability and industrial popularization, and finally prepares AlNb intermediate alloy grades of AlNb50, AlNb60 and AlNb70, and the product quality meets the use requirements of titanium alloy smelting.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of intermediate alloy, and in particular to a preparation method of an aluminum-niobium intermediate alloy for titanium alloy smelting. BACKGROUND

[0002] Titanium alloy is widely used in the field of aviation due to its small density, high specific strength, high temperature resistance, corrosion resistance, weldability and other excellent comprehensive performances.

[0003] In the production of titanium alloy, the addition of alloying elements can effectively improve some properties of the titanium alloy. However, due to the influence of factors such as density, melting point, distribution coefficient and addition method, the segregation phenomenon of uneven distribution of elements is prone to occur, and the current method of using intermediate alloy is generally used to solve the metallurgical defects caused by the above influencing factors. As an intermediate alloy for titanium alloy production, since the birth of titanium alloy, it has been considered as an important control factor and means for effectively improving the homogenization of alloy components, producing high-quality titanium alloy and improving the quality of materials, and has been paid great attention by various manufacturers.

[0004] Chinese patent publication No. CN115821083A discloses an aluminum-niobium intermediate alloy and a preparation method thereof. Potassium fluoro niobate and aluminum are used as raw materials, and the two are mixed and heated in a reaction furnace. The heating time is 10-60 min. After the reaction, the fluoroaluminate generated is floated on the surface of the reaction product. After the fluoroaluminate is poured out, the reaction product is cast to obtain an aluminum-niobium intermediate alloy with low niobium content, and the niobium content is 5.0-30.0%. This method is not suitable for industrial production in terms of raw material selection, process operation, pouring of fluoroaluminate, casting of alloy and the like, and the product is a niobium-aluminum intermediate alloy with low niobium content, which is not consistent with the original intention of selecting the intermediate alloy for titanium alloy.

[0005] Chinese patent publication No. CN102560213A discloses an aluminum-niobium intermediate alloy and a preparation method thereof. The method adopts a two-step process, and uses an off-furnace aluminothermic method for the first step of smelting. The remaining aluminum source material and the billet smelted in the first step are jointly smelted in a vacuum smelting furnace. After the furnace charge is melted, boiling refining is performed, and alloy casting is performed after the refining is completed. The two-step method adds Al twice, so that the uniformity of the composition is better than that of one-time addition. The prepared alloy component Nb content is 45.0-70.0%. The disadvantage of this method is that the production cost is undoubtedly greatly increased by the two-step preparation process (aluminothermy + vacuum), which further leads to the increase of the production cost of the downstream titanium alloy. One of the factors limiting the popularization and application of titanium alloy is the high production cost.

[0006] The niobium-aluminum alloy and the preparation method thereof disclosed in Chinese patent publication No. CN115478200A use niobium source, aluminum source, slag forming agent and heat generating agent as raw materials, the raw materials are preheated to 100-120 DEG C and then put into a reaction furnace, the reaction furnace needs to be heated to 150-200 DEG C, and then aluminum thermal reduction reaction is carried out, and the obtained niobium-aluminum alloy has a Nb content of 60.0-65.0%. The method separately heats the raw materials and the furnace, which significantly increases the complexity of the process flow in actual production, greatly reduces the production efficiency of enterprises, and thus increases the product manufacturing cost.

[0007] Based on the above background, the technical scheme of the present application is based on the aluminum thermal process, taking into account product quality, low cost, practicality and industrial promotion, and finally obtaining AlNb intermediate alloy grades AlNb50, AlNb60 and AlNb70, the product quality meets the requirements of titanium alloy smelting. SUMMARY

[0008] The purpose of the present application is to provide a preparation method of aluminum niobium intermediate alloy for titanium alloy smelting, taking into account product quality, low cost, practicality and industrial promotion, and finally obtaining AlNb intermediate alloy grades AlNb50, AlNb60 and AlNb70, the product quality meets the requirements of titanium alloy smelting.

[0009] To achieve the above purpose, the technical scheme of the present application is as follows:

[0010] A preparation method of aluminum niobium intermediate alloy for titanium alloy smelting, comprising the following steps:

[0011] 1) The raw materials include main raw material niobium pentoxide, reducing agent aluminum powder, slag forming agent calcium oxide and calcium fluoride, and the above raw materials are mixed and pretreated;

[0012] 2) Put the mixture of step 1) into a reaction device, and add a heat supplement agent;

[0013] 3) Ignite the material to make the material undergo aluminum thermal combustion reaction;

[0014] 4) After the reaction is completed, slowly cool with the furnace, and then naturally cool to room temperature after discharging;

[0015] 5) After cooling, separate the slag and gold to obtain aluminum niobium intermediate alloy.

[0016] In the above step 1), the purity of niobium pentoxide is ≥99.40%, the purity of aluminum powder is ≥98.0%, the purity of calcium oxide is ≥90.0%, and the purity of calcium fluoride is ≥99.0%.

[0017] The material of step 1) is mixed in the following mass ratio: niobium pentoxide: aluminum powder: calcium oxide: calcium fluoride = 0.70-1.20: 0.72-1.25: 0.10-0.25: 0.10-0.15.

[0018] The mixture of step 1) is dried at 80-120℃ for 1.0-3.0h, and then mixed in a conical mixer for 1.5-3.0h, with a filling rate of 40.0%-65.0% in the conical mixer.

[0019] The heat supplement agent in step 2) is a mixture of one of saltpeter, sodium nitrate, potassium chlorate, or sodium chlorate and aluminum powder, with a mixing ratio of saltpeter or sodium nitrate or potassium chlorate or sodium chlorate: aluminum powder = 1.0: 0.1-1.0 by mass. The aluminum powder used does not affect the material ratio of step 3). The amount of heat supplement agent added is 0.1wt%-0.5wt% of the mixture of step 1).

[0020] The cooling system of the furnace body in step 4) is slow cooling for 1-3h, followed by natural cooling at room temperature.

[0021] The aluminum-niobium intermediate alloy obtained in step 5) includes AlNb50, AlNb60, and AlNb70. The composition of AlNb50 is w (Nb) = 45.0%-55.0%; the composition of AlNb60 is w (Nb) = 55.0%-65.0%; the composition of AlNb70 is w (Nb) = 65.0%-75.0%; the impurity content of the AlNb intermediate alloy is w (Fe) ≤ 0.20%, w (Si) ≤ 0.15%, w (C) ≤ 0.10%, w (O) ≤ 0.10%, w (N) ≤ 0.05%, and w (Ta) ≤ 0.10%.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] 1) The reaction process of the present application does not require external stirring intervention, and the aluminum thermal reaction is naturally separated by the density difference between the alloy and the slag.

[0024] 2) Since the present application avoids stirring operation during the aluminum thermal reaction, the slag produced during the reaction process has good compactness and can act as an air barrier, so that vacuum or high-purity inert gas protection is not required.

[0025] 3) The AlNb intermediate alloy prepared by the technology is based on the aluminum thermal process, alloy preparation process, raw material technical index, process parameter are determined, the technical scheme designed has the characteristics of low cost, short process, strong applicability, etc., and is suitable for large-scale production. The AlCr intermediate alloy customized production can be realized, and the product quality of the titanium alloy ingot can be effectively controlled.

[0026] 4) The AlNb intermediate alloy prepared by the present application has the grades of AlNb50, AlNb60 and AlNb70, and the product quality meets the use requirements of titanium alloy smelting. Compared with the prior art, the present application has the advantages of universal raw materials, short process, low cost, simple operation, no need for secondary heating furnace body, and is more suitable for industrialized large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is the process flow chart of the present application.

[0028] Figure 2 is the schematic diagram of the sampling position of the intermediate alloy application example in the present application.

[0029] Figure 3 is Figure 2 the sampling point schematic diagram of the end.

[0030] In the figure: 1-head, 2-middle, 3-tail, 4-application sample. DETAILED DESCRIPTION

[0031] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the embodiments of the present application. Obviously, the described embodiments are only used as examples, and are not used to limit the present application.

[0032] Example 1:

[0033] The method for producing the AlNb intermediate alloy in the present embodiment comprises the following steps:

[0034] 1) The ingredients are prepared in the following proportions: niobium pentoxide: metal aluminum powder: calcium oxide: calcium fluoride = 1:1.04:0.15:0.10.

[0035] The raw material technical index requirements are: niobium pentoxide purity ≥ 99.40%, metal aluminum powder purity ≥ 98.0%, calcium oxide purity ≥ 90.0%, and calcium fluoride purity ≥ 99.0%.

[0036] 2) The above mixture is dried at 100°C for 1.5h, and mixed in a double-cone mixer at a filling rate of 45.0% for 2.0h.

[0037] 3) The mixed material is put into a reaction device, and 0.5% of a heat supplement agent is added at the same time, and the heat supplement agent has nitre: metal aluminum powder = 1.0:1.0.

[0038] 4) Ignite the material to make it happen aluminum hot combustion reaction, after the reaction with the furnace slowly cooled 2h, and then naturally cooled to room temperature.

[0039] 5) Cooling, slag gold separation of AlNb50 master alloy.

[0040] The AlNb50 master alloy prepared in this example, w (Nb) : 49.88%, w (Fe) : 0.18%, w (Si) : 0.15%, w (C) : 0.041%, w (O) : 0.025%, w (N) : 0.017%, w (Ta) : 0.009%. Meet the subsequent titanium alloy smelting technology requirements.

[0041] Example 2:

[0042] The method for producing AlNb master alloy in this embodiment includes the following steps:

[0043] 1) The following proportions are prepared: niobium pentoxide: metal aluminum powder: calcium oxide: calcium fluoride = 1:0.8:0.18:0.12.

[0044] Raw material technical index requirements: niobium pentoxide purity ≥ 99.40%, metal aluminum powder purity ≥ 98.0%, calcium oxide purity ≥ 90.0%, calcium fluoride purity ≥ 99.0%.

[0045] 2) Dry the above mixture at 100°C for 2.0h, and mix in a double-cone mixer at a filling rate of 51.0% for 2.5h.

[0046] 3) Put the mixed material into the reaction device, and add 0.35% of the heat supplement agent, and the heat supplement agent is sodium nitrate: metal aluminum powder = 1.0:1.0.

[0047] 4) Ignite the material to make it happen aluminum hot combustion reaction, after the reaction with the furnace slowly cooled 2.5h, and then naturally cooled to room temperature.

[0048] 5) Cooling, slag gold separation of AlNb60 master alloy.

[0049] The AlNb60 master alloy prepared in this example, w (Nb) : 60.18%, w (Fe) : 0.17%, w (Si) : 0.14%, w (C) : 0.034%, w (O) : 0.019%, w (N): 0.009%, w (Ta) : 0.007%. Meet the subsequent titanium alloy smelting technology requirements.

[0050] Example 3:

[0051] The method for producing the AlNb intermediate alloy in this example includes the following steps:

[0052] 1) The ingredients are prepared in the following proportions: niobium pentoxide: metal aluminum powder: calcium oxide: calcium fluoride = 1.20: 0.76: 0.15: 0.15.

[0053] Raw material technical index requirements: niobium pentoxide purity ≥ 99.40%, metal aluminum powder purity ≥ 98.0%, calcium oxide purity ≥ 90.0%, calcium fluoride purity ≥ 99.0%.

[0054] 2) Dry the above mixture at 100°C for 2.5h, and mix in a double-cone mixer at a filling rate of 51.0% for 2.0h.

[0055] 3) Put the mixture into the reaction device, and add 0.20% of a heat supplement agent, with potassium chlorate: metal aluminum powder = 1.0: 0.5 in the heat supplement agent.

[0056] 4) Ignite the material to cause an aluminothermic combustion reaction, and after the reaction is complete, slowly cool in the furnace for 3.0h, and then naturally cool to room temperature.

[0057] 5) After cooling is complete, separate the slag and gold to obtain an AlNb70 intermediate alloy.

[0058] The AlNb70 intermediate alloy prepared in this example has the following composition: (Nb) : 70.11%, w (Fe) : 0.15%, w (Si) : 0.14%, w (C) : 0.028%, w (O) : 0.021%, w (N) : 0.008%, w (Ta) : 0.009%. Meet the subsequent titanium alloy smelting technology requirements.

[0059] Example 4:

[0060] The method for producing the AlNb intermediate alloy in this example includes the following steps:

[0061] 1) The ingredients are prepared in the following proportions: niobium pentoxide: metal aluminum powder: calcium oxide: calcium fluoride = 1.20: 0.86: 0.10: 0.15.

[0062] Raw material technical index requirement: niobium pentoxide purity ≥ 99.40%, aluminum powder purity ≥ 98.0%, calcium oxide purity ≥ 90.0%, calcium fluoride purity ≥ 99.0%.

[0063] 2) The above mixture is dried at 120 DEG C for 2.5h, and mixed in a double-cone mixer at a filling rate of 60.0% for 3.0h.

[0064] 3) The mixture is put into a reaction device, and 0.50% of a heat supplement agent is added, wherein the heat supplement agent is sodium chlorate: aluminum powder = 1.0:0.8.

[0065] 4) The material is ignited to cause aluminothermic combustion reaction, and after the reaction is completed, the furnace is slowly cooled for 2.5h, and then naturally cooled to room temperature.

[0066] 5) After the cooling is completed, the slag and gold are separated to obtain an AlNb65 intermediate alloy.

[0067] The AlNb60 intermediate alloy prepared in the example has w(Nb): 64.94%, w(Al): 33.0%, w(Ca): 0.14%, w(Mg): 0.15%, w(F): 0.024%, w(Si): 0.019%, w(O): 0.006%, and w(Fe): 0.008%. (Nb) (Fe) (Si) (C) (O) (N) (Ta) , which meets the subsequent titanium alloy smelting technical requirements.

[0068] Application effect:

[0069] The following application examples are combined to verify the actual use effect of the AlNb series intermediate alloy prepared by the application. Different grades of AlNb intermediate alloy are used as additives of TC21 titanium alloy, and TC21 titanium alloy ingots are prepared by VAR process smelting. The ingots are sampled and analyzed to observe whether the composition segregation of Nb element occurs. In order to ensure the validity of the verification results, the remaining process conditions are unchanged.

[0070] The sampling method is shown in Figure 2 , Figure 3 The final detection results of Nb element are shown in Table 1. The composition allowable deviation is performed according to GB / T3620.2-2007, and the detection results are shown in Table 1. Among them, the AlNb60 intermediate alloy of the example 2 is selected.

[0071] Table 1: Detection results of the application examples of the intermediate alloy

[0072]

[0073]

[0074] ​​​​​​

[0075] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent substitutions or changes according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A method for the production of an aluminum niobium master alloy for the smelting of titanium alloys, characterized in that, It comprises the following steps: 1) raw materials include niobium pentoxide, aluminum powder, calcium oxide and calcium fluoride, and the raw materials are mixed and pretreated; 2) the mixture of step 1) is put into a reaction device, and a heat supplement agent is added; 3) the material is ignited to cause aluminothermic combustion reaction; 4) after the reaction is completed, the furnace is slowly cooled, and then the material is naturally cooled to room temperature after being discharged from the furnace; 5) after the cooling is completed, the slag and gold are separated, and an aluminum-niobium master alloy is obtained; The heat supplement agent in step 2) is a mixture of one of saltpeter, sodium nitrate, potassium chlorate and sodium chlorate and aluminum powder, and the mixing ratio is saltpeter or sodium nitrate or potassium chlorate or sodium chlorate: aluminum powder = 1.0:0.1~1.0 by mass, and the addition amount of the heat supplement agent is 0.1wt%-0.5wt% of the mixture in step 1); The purity of niobium pentoxide in step 1) is ≥99.40%, the purity of aluminum powder is ≥98.0%, the purity of calcium oxide is ≥90.0%, and the purity of calcium fluoride is ≥99.0%; The mass ratio of the materials in step 1) is as follows: niobium pentoxide: aluminum powder: calcium oxide: calcium fluoride = 0.70-1.20: 0.72-1.25: 0.10-0.25: 0.10-0.15; The mixture pretreatment in step 1) is that the mixture after batching is dried at 80-120℃ for 1.0-3.0h, and mixed in a mixer for 1.5-3.0h, and the filling rate in the mixer is 40.0%-65.0%; The furnace cooling system in step 4) is slowly cooled in the furnace for 1-3h.

2. A process for the production of an aluminium niobium master alloy for titanium alloy melting according to claim 1, characterized in that, The aluminum niobium intermediate alloy obtained in the above step 5) includes AlNb50, AlNb60, AlNb70; wherein the composition index of AlNb50 is: w （Nb） =45.0%-55.0%; the composition index of AlNb60 is: w （Nb） =55.0%-65.0%; the composition index of AlNb70 is: w （Nb） =65.0%-75.0%; the impurity content requirement of AlNb intermediate alloy is: w （Fe） ≤0.20%, w （Si） ≤0.15%, w （C） ≤0.10%, w （O） ≤0.10%, w （N） ≤0.05%, w （Ta） ≤0.10%.

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