Aluminum-chromium-carbon intermediate alloy and preparation method and application thereof

Abstract

The invention discloses an aluminum-chromium-carbon intermediate alloy as well as a preparation method and application thereof, and relates to the field of aluminum intermediate alloys, the aluminum-chromium-carbon intermediate alloy comprises the following elements in percentage by mass: 5-20% of Cr, 0.2-1% of C and the balance of Al; the preparation method comprises the following steps: S1, mixing a chromium source, polyvinyl alcohol, phenolic resin and a fluxing agent, and performing compression molding to obtain a pressed block; s2, an aluminum source is divided into a molten aluminum part and a cooled aluminum part, the molten aluminum is taken to be molten, the temperature is increased to 850-900 DEG C, refining and slagging are conducted, the pressed blocks are added, even stirring is conducted, the temperature is increased to 900-1200 DEG C, heating is stopped after alloying is completed, then the cooled aluminum is added, even stirring is conducted, and alloy molten aluminum is obtained; and S3, the alloy aluminum liquid is subjected to casting forming, and the aluminum-chromium-carbon intermediate alloy is obtained. According to the aluminum-chromium-carbon intermediate alloy, when the chromium-containing metal alloy material is prepared, the element chromium is introduced, and the aluminum-chromium-carbon intermediate alloy can be used together with the aluminum-titanium-boron refiner, so that the failure of the added aluminum-titanium-boron refiner is avoided.

Description

Technical Field

[0001] The invention relates to the field of aluminum master alloys, in particular to an aluminum-chromium-carbon master alloy and a preparation method and application thereof. Background Art

[0002] As a common refiner, aluminum-titanium-boron refiner can optimize the microstructure and chemical properties of alloys and meet the high standards required in different fields. Therefore, it has been widely used in the preparation of metal alloys.

[0003] In the prior art, in the process of preparing chromium-containing metal alloy materials, chromium is generally added in the form of aluminum-chromium master alloy. When aluminum-titanium-boron refiners are added at the same time, chromium easily forms intermetallic compounds with titanium and boron elements in the aluminum-titanium-boron refiners, thereby causing the aluminum-titanium-boron refiners to fail, resulting in coarse grains of the metal alloy and reduced mechanical properties.

[0004] In order to solve this problem, in some processing processes, the aluminum titanium boron refiner is replaced by other available refiners, such as aluminum titanium carbon refiner. However, the aluminum titanium carbon refiner is expensive and has a low penetration rate. Therefore, aluminum titanium boron refinement is still the main method in actual production. Summary of the invention

[0005] The invention provides an aluminum-chromium-carbon master alloy and a preparation method and application thereof, so as to solve the problem that an aluminum-titanium-boron refiner is easily ineffective when preparing a chromium-containing metal alloy.

[0006] In order to achieve the above purpose, the specific scheme adopted by the present invention is: an aluminum-chromium-carbon master alloy for preparing a chromium-containing metal alloy, the aluminum-chromium-carbon master alloy is composed of the following elements in percentage by mass: Cr: 5-20%, C: 0.2-1%, and the balance is Al.

[0007] A method for preparing an aluminum-chromium-carbon master alloy comprises the following steps:

[0008] S1: mixing a chromium source, polyvinyl alcohol, phenolic resin and flux, and pressing them into a pressed block;

[0009] S2: Divide the aluminum source into two parts: molten aluminum and cooled aluminum. Melt the molten aluminum and heat it to 850-900°C, refine and slag, add the pressed block, stir evenly, heat it to 900-1200°C, stop heating after alloying, add cooled aluminum, stir evenly, and obtain alloy aluminum liquid.

[0010] S3: Casting the alloy aluminum liquid to obtain the aluminum-chromium-carbon master alloy.

[0011] As a further optimization of the above technical solution, the chromium source is chromium powder with a chromium content ≥ 98%, and the aluminum source is an aluminum block with an aluminum content ≥ 99.7%.

[0012] As a further optimization of the above technical solution, the temperature during casting of the alloy aluminum liquid is 900-1100°C.

[0013] As a further optimization of the above technical solution, the flux is composed of 80% potassium fluoroaluminate and 20% aluminum powder in mass percentage, wherein the particle size of the aluminum powder is less than 200 meshes.

[0014] As a further optimization of the above technical solution, the ratio of the added amounts of chromium source, polyvinyl alcohol, phenolic resin and aluminum source is 5-20:0.2-1:0.2-1:85-95.

[0015] As a further optimization of the above technical solution, the mass ratio of molten aluminum to cooled aluminum is 4 to 9:1.

[0016] The invention discloses an application of an aluminum-chromium-carbon master alloy in the preparation of a chromium-containing metal alloy. The chromium-containing metal alloy is added with an AlTi5B refiner during the preparation process.

[0017] As a further optimization of the above technical solution, the chromium-containing metal alloy is an aluminum alloy that needs to add chromium elements and refine the grains.

[0018] As a further optimization of the above technical solution, aluminum-chromium-carbon intermediate alloy is added to the aluminum melt, stirred evenly, and the temperature of the aluminum melt is controlled to be 720-725°C, AlTi5B refiner is added, stirred, kept warm for 2 minutes, and cast to obtain chromium-containing aluminum alloy.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The invention prepares an aluminum-chromium-carbon master alloy, which can realize the introduction of elemental chromium when preparing a chromium-containing metal alloy material. At the same time, the aluminum-chromium-carbon master alloy can also be used together with an aluminum-titanium-boron refiner to avoid causing the added aluminum-titanium-boron refiner to fail.

[0021] The aluminum-chromium-carbon master alloy prepared by the present invention can replace the aluminum-chromium master alloy in aluminum alloys, improve the refining effect of the chromium-containing aluminum alloy using the AlTi5B refiner, reduce the grain size of the chromium-containing aluminum alloy, and compensate for the poisoning effect of the chromium element on the AlTi5B refiner.

[0022] Aluminum-chromium-carbon master alloy is an additive used only when a chromium source is needed. The master alloy already contains a certain amount of carbon. On this basis, the use of aluminum-titanium-boron refiner can achieve a good effect. This is because the reason why the aluminum-titanium-boron refiner fails in chromium-containing aluminum alloys is mainly because the TiB2 that plays a role in heterogeneous nucleation reacts with the chromium element to generate Cr x B y Or (Ti,Cr)x B y The present invention adds a small amount of carbon element while adding the chromium source. The carbon element will preferentially react with the chromium element to form chromium carbide, thereby hindering the reaction between the boron element and the chromium element in the aluminum-titanium-boron, and ensuring the effectiveness of the aluminum-boron-titanium refiner.

[0023] The invention adopts two organic substances, polyvinyl alcohol and phenolic resin, as carbon sources, adds a special flux and chromium powder and mixes them in proportion, and then presses them into round cakes. The round cakes are added into molten aluminum to obtain a relatively stable carbon content, thereby realizing the preparation of aluminum-chromium-carbon master alloy. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further elaborated in detail below in conjunction with specific embodiments. The parts of the present invention that are not described and disclosed in detail in the following embodiments should be understood as the prior art known or should be known to those skilled in the art.

[0025] To avoid repetition, the relevant technical parameters involved in the specific embodiments of the present invention are first explained as follows:

[0026] In the preparation process of the aluminum-chromium-carbon intermediate alloy of the present invention, the addition amounts of various raw materials and auxiliary materials are all based on the mass ratio. The raw materials used include aluminum source, chromium source and carbon source, the aluminum source is an aluminum block with an aluminum content of ≥99.7%, the chromium source is a metal chromium powder with a chromium content of ≥98%, and the carbon source uses organic polyvinyl alcohol and phenolic resin; the auxiliary materials used include flux, refining agent and slag-breaking agent, wherein, in terms of mass percentage, the flux is composed of 80% of potassium fluoroaluminate and 20% of aluminum powder, and the particle size of the aluminum powder is less than 200 meshes; the refining agent and the slag-breaking agent are both commercially available products, and the components of the refining agent are: NaCl, KCl, Na3AlF6, Na2SiF6, CeCl3, MgF2 and SiO2 with a particle size of less than 200 meshes; the components of the slag-breaking agent are NaCl, KCl, Na2SiF6, NaNO3 and NaCO3.

[0027] Example 1

[0028] A method for preparing an aluminum-chromium-carbon master alloy comprises the following steps:

[0029] 1) Prepare raw materials, auxiliary materials, tools and equipment, keep raw materials and auxiliary materials dry, and preheat tools;

[0030] 2) Take 75 parts of metallic chromium powder, 4 parts of polyvinyl alcohol, 4 parts of phenolic resin and 17 parts of flux, mix them evenly, and press them into several round cakes of 500-1000g;

[0031] 3) Weigh the aluminum block and the round cake, the mass ratio of the aluminum block to the round cake is 100:7.1, divide the aluminum block into two parts, one part is used as molten aluminum, and the other part is used as cooling aluminum, the mass ratio of molten aluminum to cooling aluminum is 5:1.

[0032] 4) Put the molten aluminum into a crucible to melt it into aluminum liquid, and heat it to 850°C, add a refining agent to refine and slag;

[0033] 5) Add the round cakes weighed in step 3) to the aluminum liquid in step 4) in batches, 2-3 kg at a time, and stir quickly after each addition to disperse the round cakes quickly until all the round cakes are dispersed in the aluminum liquid, and then continue to heat to 900°C and keep warm for 10-20 minutes to complete the alloying;

[0034] 6) After alloying is completed, stop heating, add cooling aluminum blocks, stir evenly, and obtain alloy aluminum liquid;

[0035] 7) Scoop out the flux on the surface of the alloy aluminum liquid and add slag remover to clean the alloy aluminum liquid.

[0036] 8) The alloy aluminum liquid is heated to 900° C. and cast into a waffle ingot, which is an aluminum-chromium-carbon intermediate alloy.

[0037] The components of the aluminum-chromium-carbon master alloy prepared in this embodiment were detected, and the detection values ​​of the aluminum-chromium-carbon master alloy were: Cr%=5.03, C%=0.21, and the balance was Al.

[0038] Example 2

[0039] A method for preparing an aluminum-chromium-carbon master alloy comprises the following steps:

[0040] 1) Prepare raw materials, auxiliary materials, tools and equipment, keep raw materials and auxiliary materials dry, and preheat tools;

[0041] 2) Take 65 parts of metallic chromium powder, 10 parts of polyvinyl alcohol, 10 parts of phenolic resin and 15 parts of flux, mix them evenly, and press them into several round cakes of 500-1000g;

[0042] 3) Weigh the aluminum block and the round cake, the mass ratio of the aluminum block to the round cake is 100:8.4, divide the aluminum block into two parts, one part is used as molten aluminum, and the other part is used as cooling aluminum, the mass ratio of the molten aluminum to the cooling aluminum is 4:1.

[0043] 4) Put the molten aluminum into a crucible to melt it into aluminum liquid, and heat it to 870°C, add a refining agent to refine and slag;

[0044] 5) Add the round cakes weighed in step 3) to the aluminum liquid in step 4) in batches, 2-3 kg at a time, and stir quickly after each addition to disperse the round cakes quickly until all the round cakes are dispersed in the aluminum liquid, and then continue to heat to 1000°C and keep warm for 10-20 minutes to complete the alloying;

[0045] 6) After alloying is completed, stop heating, add cooling aluminum blocks, stir evenly, and obtain alloy aluminum liquid;

[0046] 7) Scoop out the flux on the surface of the alloy aluminum liquid and add slag remover to clean the alloy aluminum liquid.

[0047] 8) The alloy aluminum liquid is heated to 1000° C. and cast into a waffle ingot, which is an aluminum-chromium-carbon master alloy.

[0048] The components of the aluminum-chromium-carbon master alloy prepared in this embodiment were detected, and the detection values ​​of the aluminum-chromium-carbon master alloy were: Cr%=5.12, C%=0.53, and the balance was Al.

[0049] Example 3

[0050] A method for preparing an aluminum-chromium-carbon master alloy comprises the following steps:

[0051] 1) Prepare raw materials, auxiliary materials, tools and equipment, keep raw materials and auxiliary materials dry, and preheat tools;

[0052] 2) Take 75 parts of metallic chromium powder, 2 parts of polyvinyl alcohol, 2 parts of phenolic resin and 19 parts of flux, mix them evenly, and press them into several round cakes of 500-1000g;

[0053] 3) Weigh the aluminum block and the round cake, the mass ratio of the aluminum block to the round cake is 100:12, and divide the aluminum block into two parts, one part is used as molten aluminum, and the other part is used as cooling aluminum, and the mass ratio of molten aluminum to cooling aluminum is 7:1.

[0054] 4) Put the molten aluminum into a crucible to melt it into aluminum liquid, and heat it to 900°C, add a refining agent to refine and slag;

[0055] 5) Add the round cakes weighed in step 3) to the aluminum liquid in step 4) in batches, 2-3 kg at a time, and stir quickly after each addition to disperse the round cakes quickly until all the round cakes are dispersed in the aluminum liquid, and then continue to heat to 1200°C and keep warm for 10-20 minutes to complete the alloying;

[0056] 6) After alloying is completed, stop heating, add cooling aluminum blocks, stir evenly, and obtain alloy aluminum liquid;

[0057] 7) Scoop out the flux on the surface of the alloy aluminum liquid and add slag remover to clean the alloy aluminum liquid.

[0058] 8) The alloy aluminum liquid is heated to 1100° C. and cast into a waffle ingot, which is an aluminum-chromium-carbon master alloy.

[0059] The components of the aluminum-chromium-carbon master alloy prepared in this embodiment were detected, and the detection values ​​of the aluminum-chromium-carbon master alloy were: Cr%=10.23, C%=0.25, and the balance was Al.

[0060] Example 4

[0061] A method for preparing an aluminum-chromium-carbon master alloy comprises the following steps:

[0062] 1) Prepare raw materials, auxiliary materials, tools and equipment, keep raw materials and auxiliary materials dry, and preheat tools;

[0063] 2) Mix 65 parts of metallic chromium powder, 10 parts of polyvinyl alcohol, 10 parts of phenolic resin and 15 parts of flux evenly, and press into several round cakes of 500-1000 g;

[0064] 3) Weigh the aluminum block and the round cake, the mass ratio of the aluminum block to the round cake is 100:18.2, divide the aluminum block into two parts, one part is used as molten aluminum, and the other part is used as cooling aluminum, and the mass ratio of molten aluminum to cooling aluminum is 6:1.

[0065] 4) Put the molten aluminum into a crucible to melt it into aluminum liquid, and heat it to 900°C, add a refining agent to refine and slag;

[0066] 5) Add the round cakes weighed in step 3) to the aluminum liquid in step 4) in batches, 2-3 kg at a time, and stir quickly after each addition to disperse the round cakes quickly until all the round cakes are dispersed in the aluminum liquid, and then continue to heat to 1200°C and keep warm for 10-20 minutes to complete the alloying;

[0067] 6) After alloying is completed, stop heating, add cooling aluminum blocks, stir evenly, and obtain alloy aluminum liquid;

[0068] 7) Scoop out the flux on the surface of the alloy aluminum liquid and add slag remover to clean the alloy aluminum liquid.

[0069] 8) The alloy aluminum liquid is heated to 1000° C. and cast into a waffle ingot, which is an aluminum-chromium-carbon master alloy.

[0070] The components of the aluminum-chromium-carbon master alloy prepared in this embodiment were detected, and the detected values ​​of the aluminum-chromium-carbon master alloy were: Cr%=10.10, C%=0.98, and the balance was Al.

[0071] Example 5

[0072] A method for preparing an aluminum-chromium-carbon master alloy comprises the following steps:

[0073] 1) Prepare raw materials, auxiliary materials, tools and equipment, keep raw materials and auxiliary materials dry, and preheat tools;

[0074] 2) Take 75 parts of metallic chromium powder, 1 part of polyvinyl alcohol, 1 part of phenolic resin and 23 parts of flux, mix them evenly, and press them into several round cakes of 500-1000g;

[0075] 3) Weigh the aluminum block and the round cake, the mass ratio of the aluminum block to the round cake is 100:36, divide the aluminum block into two parts, one part is used as molten aluminum, and the other part is used as cooling aluminum, the mass ratio of molten aluminum to cooling aluminum is 9:1.

[0076] 4) Put the molten aluminum into a crucible to melt it into aluminum liquid, and heat it to 900°C, add a refining agent to refine and slag;

[0077] 5) Add the round cakes weighed in step 3) to the aluminum liquid in step 4) in batches, 2-3 kg at a time, and stir quickly after each addition to disperse the round cakes quickly until all the round cakes are dispersed in the aluminum liquid, and then continue to heat to 1200°C and keep warm for 10-20 minutes to complete the alloying;

[0078] 6) After alloying is completed, stop heating, add cooling aluminum blocks, stir evenly, and obtain alloy aluminum liquid;

[0079] 7) Scoop out the flux on the surface of the alloy aluminum liquid and add slag remover to clean the alloy aluminum liquid.

[0080] 8) The alloy aluminum liquid is heated to 1000° C. and cast into a waffle ingot, which is an aluminum-chromium-carbon master alloy.

[0081] The components of the aluminum-chromium-carbon master alloy prepared in this embodiment were detected, and the detected values ​​of the aluminum-chromium-carbon master alloy were: Cr%=19.23, C%=0.22, and the balance was Al.

[0082] Example 6

[0083] A method for preparing an aluminum-chromium-carbon master alloy comprises the following steps:

[0084] 1) Prepare raw materials, auxiliary materials, tools and equipment, keep raw materials and auxiliary materials dry, and preheat tools;

[0085] 2) Take 70 parts of metallic chromium powder, 5 parts of polyvinyl alcohol, 5 parts of phenolic resin and 20 parts of flux, mix them evenly, and press them into several round cakes of 500-1000g;

[0086] 3) Weigh the aluminum block and the round cake, the mass ratio of the aluminum block to the round cake is 100:34, divide the aluminum block into two parts, one part is used as molten aluminum, and the other part is used as cooling aluminum, the mass ratio of molten aluminum to cooling aluminum is 8:1.

[0087] 4) Put the molten aluminum into a crucible to melt it into aluminum liquid, and heat it to 870°C, add a refining agent to refine and slag;

[0088] 5) Add the round cakes weighed in step 3) to the aluminum liquid in step 4) in batches, 2-3 kg at a time, and stir quickly after each addition to disperse the round cakes quickly until all the round cakes are dispersed in the aluminum liquid, and then continue to heat to 1000°C and keep warm for 10-20 minutes to complete the alloying;

[0089] 6) After alloying is completed, stop heating, add cooling aluminum blocks, stir evenly, and obtain alloy aluminum liquid;

[0090] 7) Scoop out the flux on the surface of the alloy aluminum liquid and add slag remover to clean the alloy aluminum liquid.

[0091] 8) The alloy aluminum liquid is heated to 980° C. and cast into a waffle ingot, which is an aluminum-chromium-carbon intermediate alloy.

[0092] The components of the aluminum-chromium-carbon master alloy prepared in this embodiment were detected, and the detection values ​​of the aluminum-chromium-carbon master alloy were: Cr%=20.34, C%=0.95, and the balance was Al.

[0093] Example 7

[0094] Take 96 kg of aluminum ingots, the aluminum content in the aluminum ingot is ≥99.7%, the same below, melt the aluminum ingot into aluminum liquid, add 4 kg of the aluminum-chromium-carbon master alloy prepared in Example 1, stir evenly, and control the temperature of the aluminum liquid to 720-725°C, add 200 g of AlTi5B refiner, stir evenly, keep warm for 2 minutes, and cast to obtain a chromium-containing aluminum alloy sample.

[0095] The grain size of the corrosion-checked specimens was measured to have an average grain size of 280 μm.

[0096] Examples 8-12

[0097] The overall steps of Examples 8-12 are the same as those of Example 7, the main difference being that the aluminum-chromium-carbon master alloys prepared in Examples 2-6 are added respectively, and the amounts of aluminum ingots and aluminum-chromium-carbon master alloys added are different. The specific test results are shown in Table 1 below.

[0098] Table 1

[0099] Comparative Example 1

[0100] Take 96 kg of pure aluminum ingot, add 4 kg of commercially available AlCr5 master alloy after melting, stir evenly, control the aluminum liquid temperature to 720-725°C, add 200 g of AlTi5B refiner, stir evenly, keep warm for 2 minutes, and cast to obtain a chromium-containing aluminum alloy sample.

[0101] The grain size of the corrosion-checked specimens was measured to have an average grain size of 384 μm.

[0102] Comparative Examples 2-6

[0103] The overall steps of Comparative Examples 2-6 are the same as those of Comparative Example 1, the main difference being the different amounts of aluminum ingots and aluminum-chromium-carbon master alloys added. The specific test results are shown in Table 2 below.

[0104] Table 2

[0105] The test results of Tables 1 and 2 are analyzed: For Comparative Examples 1-6, chromium is introduced into the raw materials in the form of aluminum-chromium master alloys. When AlTi5B refiner is added, the average grain size of the obtained samples is 370-390μm; while for Examples 7-12, the aluminum-chromium-carbon master alloy prepared by the present invention is added to the raw materials to introduce chromium. When AlTi5B refiner is also added and other reaction conditions are the same, the average grain size of the obtained samples is below 290μm. It can be seen that in the preparation process of the chromium-containing metal alloy, the grain size is finer when the same proportion of AlTi5B refiner is added compared with the use of the aluminum-chromium master alloy. The aluminum-chromium-carbon master alloy prepared by the present invention can be used together with the aluminum-titanium-boron refiner to avoid causing the added aluminum-titanium-boron refiner to fail.

[0106] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An aluminum-chromium-carbon master alloy for preparing a chromium-containing metal alloy, characterized in that: The aluminum-chromium-carbon master alloy is composed of the following elements in percentage by mass: Composition: Cr: 5-20%, C: 0.2-1%, and the balance is Al.

2. A method for preparing the aluminum-chromium-carbon master alloy as claimed in claim 1, characterized in that: The following steps are involved: S1: mixing a chromium source, polyvinyl alcohol, phenolic resin and flux, and pressing them into a pressed block; S2: dividing the aluminum source into two parts, molten aluminum and cooled aluminum, taking the molten aluminum to melt and heating it to 850-900°C, refining and slagging, adding the pressed block, stirring evenly, heating it to 900-1200°C, keeping the temperature, stopping heating after alloying, adding the cooled aluminum, stirring evenly, and obtaining alloy aluminum liquid; S3: Casting the alloy aluminum liquid to obtain the aluminum-chromium-carbon master alloy.

3. The method for preparing an aluminum-chromium-carbon master alloy according to claim 2, characterized in that: The chromium source is chromium powder with a chromium content of ≥98%, and the aluminum source is an aluminum block with an aluminum content of ≥99.7%.

4. The method for preparing an aluminum-chromium-carbon master alloy according to claim 2, characterized in that: The temperature of the alloy aluminum liquid during casting is 900-1100°C.

5. The method for preparing an aluminum-chromium-carbon master alloy according to claim 2, characterized in that: In terms of mass percentage, the flux consists of 80% potassium fluoroaluminate and 20% aluminum powder, wherein the particle size of the aluminum powder is less than 200 meshes.

6. The method for preparing an aluminum-chromium-carbon master alloy according to claim 2, characterized in that: The added amount ratio of the chromium source, polyvinyl alcohol, phenolic resin and aluminum source is: 5-20: 0.2-1: 0.2-1: 85-95.

7. The method for preparing an aluminum-chromium-carbon master alloy according to claim 2, characterized in that: The mass ratio of molten aluminum to cooled aluminum is 4 to 9:

1.

8. Use of the aluminum-chromium-carbon master alloy as claimed in claim 1 in the preparation of a chromium-containing metal alloy, characterized in that: The chromium-containing metal alloy is added with AlTi5B refiner during the preparation process.

9. The use of an aluminum-chromium-carbon master alloy in the preparation of a metal alloy according to claim 8, characterized in that: The chromium-containing metal alloy is an aluminum alloy to which chromium elements need to be added and to which grains need to be refined.

10. The use of an aluminum-chromium-carbon master alloy in the preparation of a metal alloy according to claim 9, characterized in that: Add the aluminum-chromium-carbon master alloy as claimed in claim 1 to the aluminum melt, stir evenly, control the temperature of the aluminum melt to 720-725° C., add AlTi5B refiner, stir, keep warm for 2 minutes, and cast to obtain a chromium-containing aluminum alloy.

Images