Wear-resistant low-carbon aluminum alloy and its preparation method

Abstract

The present invention provides a wear-resistant low-carbon aluminum alloy and a preparation method thereof, relating to the technical field of aluminum alloy preparation. The wear-resistant low-carbon aluminum alloy is composed of Si, Mg, Mn, Cu, Zr, Ti, Zn, Ce, La and Al, wherein the mass ratio of Ce to La is 2:1, the mass ratio of Mg to Mn is 1:1, and during the preparation process, each component is melted, then cast and subjected to variable-temperature heat treatment, and then nitrogen is filled for heat preservation and vacuum microwave heat treatment. The present invention overcomes the deficiencies of the prior art, effectively guarantees the tensile strength of the aluminum alloy, and on this basis, improves the hardness and wear resistance of the aluminum alloy, comprehensively improving the performance of the aluminum alloy.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy preparation, and particularly relates to a wear-resistant low-carbon aluminum alloy and a preparation method thereof. Background Art

[0002] Aluminum alloys have the characteristics of low density, good processing performance, corrosion resistance, etc., and are widely used in the fields of aerospace, ship machinery, etc. However, aluminum alloy structural parts are often subject to wear in different ways such as reciprocating sliding, erosion, and wear corrosion in the service environment, which greatly reduces the service life of aluminum alloy components on this basis.

[0003] At present, by adjusting the silicon content in the aluminum alloy, the hardness and wear resistance of the aluminum alloy can be adjusted to a certain extent. Among them, the increase in silicon content can significantly improve the hardness and wear resistance of the aluminum alloy, but too high a silicon content will lead to a decrease in the tensile strength of the aluminum alloy, which will cause the application of the aluminum alloy to a certain extent. Therefore, how to improve the wear resistance of the aluminum alloy on the basis of ensuring a high tensile strength is the main research direction at present. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a wear-resistant low-carbon aluminum alloy and a preparation method thereof, which effectively ensure the tensile strength of the aluminum alloy, and on this basis, improve the hardness and wear resistance of the aluminum alloy, and comprehensively improve the performance of the aluminum alloy.

[0005] To achieve the above object, the technical solution of the present invention is realized through the following technical solutions:

[0006] A wear-resistant low-carbon aluminum alloy, which is composed of the following raw materials in mass percentage: Si: 4%-8%, Mg: 0.8%-1.0%, Mn: 0.8%-1.0%, Cu: 1.2%-1.5%, Zr: 0.2%-0.3%, Ti: 0.1%-0.3%, Zn: 2.2%-2.6%, Ce: 0.08%-0.12%, La: 0.04%-0.06%, the rest is Al and unavoidable impurities, and the mass ratio of Ce to La is 2:1, and the mass ratio of Mg to Mn is 1:1.

[0007] The preparation method of the wear-resistant low-carbon aluminum alloy includes the following steps:

[0008] S1. Heat and melt the aluminum ingot, add zinc blocks and magnesium blocks, continue to heat up to 800-850°C after melting, and then add aluminum-copper master alloy and continue to heat and melt to obtain molten metal for standby;

[0009] S2. Add aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-zirconium master alloy, aluminum-titanium master alloy, and aluminum-lanthanum-cerium master alloy to the above molten metal, keep it molten and incubate, and obtain incubated molten metal for standby;

[0010] S3. Add a refining agent to the above inoculated molten metal, refine to remove slag, then conduct a composition analysis, adjust the content of each component to meet the standards, and then perform a heat preservation treatment for 30 - 40 min to obtain a standby alloy liquid;

[0011] S4. Cast the above alloy liquid into a mold, then conduct a heat preservation treatment at a temperature of 300 - 350 °C for 1 - 2 h, then cool down to 120 - 150 °C and continue the heat preservation treatment for 30 - 40 min, then fill with nitrogen to increase the pressure to 0.2 - 0.3 Mpa, and heat up to 450 - 550 °C for heat treatment for 1 - 2 h, and then return to normal pressure and cool down to room temperature to obtain a standby alloy blank;

[0012] S5. Vacuum microwave heat - treat the above alloy blank at a temperature of 350 - 450 °C for 15 - 20 min, then quickly cool down to 200 - 250 °C, conduct a heat preservation treatment for 40 - 60 min, and then cool down to room temperature in a room - temperature environment to obtain a wear - resistant low - carbon aluminum alloy.

[0013] Preferably, in step S1, the temperature when adding the zinc block and the magnesium block is controlled at 700 - 800 °C, and the melting time of the zinc block and the magnesium block is controlled at 20 - 40 min.

[0014] Preferably, in step S1, the temperature for adding the aluminum - copper master alloy and continuing to heat and melt is 850 - 900 °C, and the melting time is 15 - 20 min.

[0015] Preferably, in step S2, the temperature for heat preservation and inoculation after melting is 800 - 850 °C, and the inoculation time is 40 - 80 min.

[0016] Preferably, in step S3, the refining agent is obtained by mixing KCl, NaCl, CaF2, and NaF in a mass ratio of 3:2:1:0.6, and the addition amount of the refining agent is 0.2% - 0.5% of the total mass of the inoculated molten metal.

[0017] Preferably, in step S3, the temperature for refining and slag removal is 740 - 760 °C, and the refining time is 40 - 60 min.

[0018] Preferably, in step S4, the cooling rate is 10 - 15 °C / min, and the heating rate is 8 - 12 °C / min.

[0019] Preferably, in step S5, the rapid - cooling rate is 20 - 30 °C / min.

[0020] The present invention provides a wear - resistant low - carbon aluminum alloy and its preparation method. Compared with the prior art, the advantages are as follows:

[0021] The present invention controls the silicon content in the aluminum alloy, adds a certain content of Ce and La, and simultaneously controls the addition ratios of Ce and La as well as the addition ratios of Mg and Mn, which can effectively ensure the tensile strength of the aluminum alloy, and further improve the hardness and wear resistance of the alloy. Subsequently, the present invention combines variable-temperature heat treatment and vacuum microwave heat treatment to effectively treat the alloy surface, comprehensively improve the hardness and wear resistance of the alloy surface, and enhance the application effect of the alloy. Detailed implementation mode

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, rather than all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] The refining agent used in the following examples and comparative examples has the following mass ratio of components: KCl∶NaCl∶CaF2∶NaF is mixed in a mass ratio of 3∶2∶1∶0.6.

[0024] Example 1:

[0025] Preparation of aluminum alloy:

[0026] (1) Heat the aluminum ingot to 700°C and melt it, then add zinc blocks and magnesium blocks and continue melting for 30 minutes. Then raise the temperature to 800°C and add aluminum-copper master alloy, and continue to raise the temperature to 850°C and melt for 20 minutes to obtain molten metal for standby;

[0027] (2) Add aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-zirconium master alloy, aluminum-titanium master alloy, and aluminum-lanthanum-cerium master alloy to the above molten metal, keep it molten at 800°C and incubate for 80 minutes to obtain incubated molten metal for standby;

[0028] (3) Add 0.2% of the refining agent based on the total mass of the incubated molten metal to the above incubated molten metal, refine and remove slag at 740°C for 60 minutes, and then conduct component analysis and adjust the mass percentages of each component as follows:

[0029] Si: 4%, Mg: 0.8%, Mn: 0.8%, Cu: 1.2%, Zr: 0.2%, Ti: 0.1%, Zn: 2.2%, Ce: 0.08%, La: 0.04%, and the rest are Al and inevitable impurities;

[0030] Then conduct heat preservation treatment for 40 minutes to obtain alloy liquid for standby;

[0031] (4) Cast the above alloy liquid into a mold, then keep it at 300 °C for 2 h, cool it at a rate of 10 °C / min to 120 °C and continue to keep it for 40 min, then heat it at a rate of 8 °C / min to 450 °C, increase the pressure to 0.2 Mpa, carry out heat treatment under nitrogen protection for 2 h, and then cool it to room temperature after returning to normal pressure to obtain an alloy blank for standby;

[0032] (5) Vacuum microwave heat-treat the above alloy blank at 350 °C for 20 min, then quickly cool it at a rate of 20 °C / min to 200 °C, keep it for 60 min, and then cool it to room temperature in a room-temperature environment to obtain wear-resistant low-carbon aluminum alloy.

[0033] Example 2:

[0034] Preparation of aluminum alloy:

[0035] (1) Heat the aluminum ingot to 800 °C to melt it, add zinc blocks and magnesium blocks and continue melting for 20 min, then heat it to 850 °C and add aluminum-copper master alloy and continue heating to 900 °C for melting for 15 min to obtain molten metal for standby;

[0036] (2) Add aluminum-silicon master alloy, aluminum-manganese master alloy, aluminum-zirconium master alloy, aluminum-titanium master alloy, and aluminum-lanthanum-cerium master alloy to the above molten metal, keep it at 850 °C for melting and inoculation for 40 min to obtain inoculated molten metal for standby;

[0037] (3) Put a refining agent accounting for 0.5% of the total mass of the inoculated molten metal into the above inoculated molten metal, refine and remove slag at 760 °C for 40 min, and then conduct component analysis and adjust the mass percentages of each component as follows:

[0038] Si: 8%, Mg: 1.0%, Mn: 1.0%, Cu: 1.5%, Zr: 0.3%, Ti: 0.3%, Zn: 2.6%, Ce: 0.12%, La: 0.06%, and the rest is Al and unavoidable impurities;

[0039] Then keep it for 30 min to obtain alloy liquid for standby;

[0040] (4) Cast the above alloy liquid into a mold, then keep it at 350 °C for 1 h, cool it at a rate of 15 °C / min to 150 °C and continue to keep it for 30 min, then heat it at a rate of 12 °C / min to 550 °C, increase the pressure to 0.3 Mpa, carry out heat treatment under nitrogen protection for 1 h, and then cool it to room temperature after returning to normal pressure to obtain an alloy blank for standby;

[0041] (5) Vacuum microwave heat-treat the above alloy billet at 450 °C for 15 min, then rapidly cool it to 250 °C at a rate of 30 °C / min, hold for 40 min, and then cool it to room temperature in a room-temperature environment to obtain wear-resistant low-carbon aluminum alloy.

[0042] Comparative Example 1:

[0043] Refer to the preparation method of Example 1 above, and only control the adjustment of the mass percentages of each component in step (3) as follows:

[0044] Si: 4%, Mg: 0.8%, Mn: 1.0%, Cu: 1.2%, Zr: 0.2%, Ti: 0.1%, Zn: 2.2%, Ce: 0.12%, La: 0.04%, and the rest is Al and unavoidable impurities.

[0045] Comparative Example 2:

[0046] Refer to the preparation method of Example 1 above, and only control the adjustment of the mass percentages of each component in step (3) as follows:

[0047] Si: 4%, Mg: 1.0%, Mn: 0.8%, Cu: 1.2%, Zr: 0.2%, Ti: 0.1%, Zn: 2.2%, Ce: 0.08%, La: 0.06%, and the rest is Al and unavoidable impurities.

[0048] Comparative Example 3:

[0049] Preparation of aluminum alloy:

[0050] Steps (1)-(3) are the same as those in Example 1;

[0051] (4) Cast and form the above alloy liquid, then hold it at 300 °C for 2 h, then cool it to 120 °C at a rate of 10 °C / min and continue to hold for 40 min, then heat it to 450 °C at a rate of 8 °C / min, heat-treat for 2 h, and then cool it to room temperature after restoring normal pressure to obtain an alloy billet for standby;

[0052] (5) Vacuum microwave heat-treat the above alloy billet at 350 °C for 20 min, then rapidly cool it to 200 °C at a rate of 20 °C / min, hold for 60 min, and then cool it to room temperature in a room-temperature environment to obtain wear-resistant low-carbon aluminum alloy.

[0053] Comparative Example 4:

[0054] Preparation of aluminum alloy:

[0055] Steps (1)-(3) are the same as those in Example 1;

[0056] (4) Cast the above alloy liquid into a mold, then keep it at 300 °C for 2 h, cool it at a rate of 10 °C / min to 120 °C and continue to keep it for 40 min, then heat it up to 450 °C at a rate of 8 °C / min, increase the pressure to 0.2 Mpa, carry out heat treatment under nitrogen protection for 2 h, and then cool it to room temperature after returning to normal pressure to obtain wear-resistant low-carbon aluminum alloy.

[0057] Detection:

[0058] 1. Tensile strength, yield strength and elongation of the aluminum alloy castings tested with reference to "GB / T 228.1-2010 Metallic materials - Tensile testing - Part 1: Method of test at room temperature" (tensile speed: 2 mm / min), test 3 points according to the standard: GB / T231.1-2009, and take the average value to obtain the Vickers hardness of each group of materials. Detect the mechanical properties of the die-cast aluminum alloys prepared in Examples 1-2 and Comparative Examples 1-4. The specific results are shown in Table 1 below:

[0059] Table 1

[0060] Group Yield strength (Mpa) Tensile strength (Mpa) Elongation rate (%) Example 1 329 Mpa 462 MPa 4.53％ Example 2 331 Mpa 463 Mpa 4.52％ Comparative Example 1 306 Mpa 415 Mpa 4.57％ Comparative Example 2 293 Mpa 402 Mpa 4.62％ Comparative Example 3 296 Mpa 405 Mpa 4.55％ Comparative Example 4 301 Mpa 410 Mpa 4.56％

[0061] 2. Detect the Vickers hardness (test 3 points with reference to GB / T231.1-2009 and take the average value) and wear rate of the aluminum alloys prepared in Examples 1-2 and Comparative Examples 1-4 (detect the wear rate by carrying out a sliding friction and wear test on each group of aluminum alloys under the test conditions of a constant speed of 400 rpm and a constant load of 7 N). The specific results are shown in Table 2 below:

[0062] Table 2

[0063] Group <![CDATA[Vickers hardness (HV, kg / mm 2 )]]> Wear rate (g / N·m) Example 1 624 3.9 Example 2 625 3.8 Comparative Example 1 593 4.5 Comparative Example 2 602 4.4 Comparative Example 3 610 4.2 Comparative Example 4 608 4.6

[0064] It can be seen from the above detection that Examples 1-2 have higher mechanical properties and higher hardness, and lower wear rate, and can achieve the wear-resistant effect.

[0065] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. Wear-resistant low-carbon aluminum alloy, characterized in that: The wear-resistant low-carbon aluminum alloy is composed of the following raw materials in percentage by mass: Composition: Si: 4%-8%, Mg: 0.8%-1.0%, Mn: 0.8%-1.0%, Cu: 1.2%-1.5%, Zr: 0.2%-0.3%, Ti: 0.1%-0.3%, Zn: 2.2%-2.6%, Ce: 0.08%-0.12%, La: 0.04%-0.06%, the rest is Al and unavoidable impurities, and the mass ratio of Ce to La is 2:1, and the mass ratio of Mg to Mn is 1:1; The method for preparing the wear-resistant low-carbon aluminum alloy comprises the following steps: S1. After heating and melting the aluminum ingot, add the zinc block and the magnesium block, continue to heat up to 800-850°C after melting, add the aluminum-copper master alloy and continue to heat and melt to obtain the molten metal for use; S2, adding aluminum silicon master alloy, aluminum manganese master alloy, aluminum zirconium master alloy, aluminum titanium master alloy and aluminum lanthanum cerium master alloy to the above molten metal, and incubating the molten metal after melting to obtain an incubated molten metal for later use; S3, adding a refining agent to the above-mentioned inoculant metal liquid, refining and removing slag, analyzing the components, adjusting the content of each component to meet the standard, and then heat-insulating for 30-40 minutes to obtain the alloy liquid for standby use; S4, casting the alloy liquid, heat-treating it at 300-350°C for 1-2h, cooling it to 120-150°C and heat-treating it for 30-40min, then filling it with nitrogen and pressurizing it to 0.2-0.3MPa, heating it to 450-550°C and heat-treating it for 1-2h, then restoring it to normal pressure and cooling it to normal temperature to obtain an alloy blank for standby use; S5. The alloy blank is subjected to vacuum microwave heat treatment at 350-450°C for 15-20 min, then rapidly cooled to 200-250°C, heat-treated for 40-60 min, and then cooled to room temperature in a room temperature environment to obtain a wear-resistant low-carbon aluminum alloy.

2. The wear-resistant low-carbon aluminum alloy according to claim 1, characterized in that: In the step S1, the temperature of the zinc block and the magnesium block when they are added is controlled at 700-800° C., and the melting time of the zinc block and the magnesium block is controlled at 20-40 minutes.

3. The wear-resistant low-carbon aluminum alloy according to claim 1, characterized in that: The temperature of adding the aluminum-copper master alloy and continuing to heat up and melt in step S1 is 850-900° C., and the melting time is 15-20 minutes.

4. The wear-resistant low-carbon aluminum alloy according to claim 1, characterized in that: In the step S2, the temperature for heat preservation and incubation after melting is 800-850° C., and the incubation time is 40-80 min.

5. The wear-resistant low-carbon aluminum alloy according to claim 1, characterized in that: In step S3, the refining agent is KCl, NaCl, CaF2, and NaF mixed in a mass ratio of 3:2:1:0.6, and the amount of the refining agent added is 0.2%-0.5% of the total mass of the inoculated metal liquid.

6. The wear-resistant low-carbon aluminum alloy according to claim 1, characterized in that: The temperature of refining and deslagging in step S3 is 740-760° C., and the refining time is 40-60 min.

7. The wear-resistant low-carbon aluminum alloy according to claim 1, characterized in that: In step S4, the cooling rate is 10-15°C / min, and the heating rate is 8-12°C / min.

8. The wear-resistant low-carbon aluminum alloy according to claim 1, characterized in that: The rapid cooling rate in step S5 is 20-30°C / min.